409ci stroker rod length

I considering doing another block and have owned a couple of 396/398 motors with the current being a 383. Trying to figure out why the 409 ci combo isn’t more popular. They were winning a lot of street races a couple of years ago but hear nothing about them now. Guess I’m looking for a little bit more torque and to be different.

What are the disadvantages of the 4’ stroke vs. 3.85? If any.

Again, this is just hearsay, but I’ve heard using a 6” rod will cause the piston to be very short causing excessive wear. Any truth to this?

What is the best rod length? I’ve heard the 5.85 rod is best with a 4” stroke due the length (shortness) of the piston (CH).

Who has pistons for the 4” stroke and 5.85 rod? I understand Eagle make a 4” crank and for $150.00 you can get it ground for 5.85 rods.

Or should I just sit down keeping my mouth shut and do another 396 and get it over with?

Denny

Denny-
409 is not popular because you are hitting the big time curve of money/pain in the ass/wear and tear vs power after a 396 for an LT1 block. but yes, I would recommend a 5.850 with a 4" stroke crank..

How much power do you want to make? Having built 3 blower cars over the last year.. and building a turbo setup for my self, I think for your use you would be much happier with a SQ trim on a nice little 383. you would be able to make 550rw+ on pump gas easily, pass emmisions, and have more drivability. Of course there is more to "go wrong"... but I still thinks its less of a hassle than a NA/solid roller combo.. because you can run a small hyd and still make big power.

if you only wanna make <420rw, then you are best off stickin NA.

but if I know you.. 420 isn't gonna be enough! you ever ridden in a 550+ rw blower car? its fun :)

Thanks Jordon.

Finally out of the closet and what I’m trying to do is come up with a reliable 450rwhp (or more!!) combo if possible. Was hoping with enough ci, great heads (I’ve not ruled out the 215 AFR’s raised runners), electric water pump and a sensible (236/242 or so) hydraulic cam, I could come pretty darn close. No more solid lifter cams for me after breaking those darn liters all the time.

I used to drive Pat’s supercharged 383 on occasion and it was powerful no doubt. My concern living here in Dallas is overheating in summer. Plus it seems like most of the people I know with supercharged cars sooner or later break pistons. Maybe it’s just me or perhaps Pat’s old car, but the throttle response was slower giving the subjective impression of being not as quick as it really was.

On second thought, if overheating is not an issue, a supercharger with different pistons for my current 383 block/heads/cam may even be cheaper and certainly does produce effortless power. All I really need is lower compression pistons, larger injectors and the supercharger. Which supercharger do you recommend? What compression? Also, don’t they like 5.7” rods? I tearing down the engine no matter what.

Thanks again for the input. Let me sleep on that one as it has real merit.

Denny

One vote for a mild 236/242 cammed 396 stroker with AFR 210's and a HydraRev kit topped with a Nitrous Express Fogger and some smallish 250hp jets...possibly a Comp Nitrous HP grind camshaft??

Just my .02 from one Denny to another.

I always respect what a Denny has to say. I've found them to be bright, charming and good looking. Real studs in every sense of the word. In adition, experts on cars by all means.

Actually my ship is sinking some on thinking about doing a 409 motor and may end up just like everybody else owning another 396.

Believe this particular list probably has the best technical expertise on the net and I'm not getting any responces in favor of the project. The guys on the Vette list jump up and down that "bigger is better" but don't seem to have the technical expertise to explains the pro' s and con's nor have they actually done one. (Think that may tell ya something)

Is anyone running the raised runner 215's on the street? I haven't e-mailed Mark Monvaleo for a while, but my understanding he sells the adapter plates so you can use a regular LT1 intake. The only kicker is Jensel rockers.

Again, I done jumping through hoops and may end up with a 396 with 210 AFR heads, but sure do like the sound of a 410 ci motor and 215 raised port heads though.

Thanks!

Jordon, I'm curious, why a 5.85" rod with a 4" stroke? That puts the rod ratio down to 1.46, instead of 1.5 with a 6" rod. Is it a physical limitation, clearancing issues, with running such a big stroke? I know rod ratio isn't the end all be all, but it would be nice to know why the 409 isn't more popular. I had always presumed that people wanted to stay above a 1.5 r/s ratio. With the reduced rod ratio there is more side-loading on the pistons, and reduced longevity, right? Maybe its to make it have peak power a bit lower in the rpm range? A better rod ratio would have characteristics of a higher reving engine, so you are effectively limiting high rpm efficiency I would guess. Then again, the stock pcm only goes to 7000, so its not a high rev option unless you go standalone. Ok, I'm through rambling for now.

i for one think it would be cool
....and also not a good idea for a engine that sees lots of miles
13 more cubes isnt a huge deal, but having something different i think is pretty cool, i say go for it

brain-
rod/stroke ratio is just a number.. it means very little. about all you wanna do is run the longest rod you can, and still have a decent size piston there.. and IMO, 6" rod doesn't leave enough piston

Denny-
a really good set of heads(215RR would be great) and a hyd cam in that range should make your desired power easily. the 215RR heads will need a hogans sheet metal intake however. there is some talk that you COULD use an LT4 intake, but it would become a major problem area...


As far as blower cars, the reason why they feel slower at low RPM is 2 fold, 1) its so friggin fast up stairs.. and 2) you generally run lower compression, which reduces low end(say 1500rpm-2500rpmish). However, you will be running a much smaller cam, which will give you more off idle response.


A properly built blower motor/combination should NOT ever hurt pistons... think of all the turbo/blower cars coming from the major automakers.

If you keep the HP low(say under 550rw), which would probably take around 10lbs of boost with good heads, I don't see why you would have any problems with pistons breaking, as long as you don't skimp on the fuel system.

This also gives you more room to grow, in the future if you decide you wanna put the car in "kill" mode, you can up the boost.

overheating should not be an issue.

with a 3.750 stroke, you can use a 6" rod. I built a blower motor for a car last xmas that uses a semi-custom SRP piston, 24cc dish, for a 6" rod. worked great. car makes over 500rw, with very little $ invested.

This is hearsay, but I heard Mark M. had an adapter plate he was selling to adapt the LT series intakes to the 215 heads. Guess I need to e-mail him to find out for sure.

The word I’m getting on doing a 4” stroke with a 6” rod is that the compression height of the piston is very low/small which puts a lot of strain on the sides of the piston. That’s why people are using the 5.85 rod instead. Again, this is also just hearsay and I’m trying to get some feedback from someone whom actually has a similar combo. There has got to be someone on this list who owns a 409 and can explain why they did one and if they would do anothe?.

Just can't believe doing .015" more stroke makes a night and day difference in the wear factor. I realize that when you push the edge things do happen faster, but shouldn't be that much faster. An 1/8th of a inch just isn't that much compared to the overall stroke.

Just being very cautious as a believe it or not, I was one of the very first to do a solid roller 396. Pretty amazing as to how many problems I had back then vs how common they are now.

The 409 wears a lot more, because you have the added stroke, AND you must run a shorter rod.

FYI, mark m at one point had 6" rods in his 4" stroke motor.. althought for continuos street use, he would prolly recommend a shorter rod.

It's not a 409, but I still have the Excell spec sheet where Mark Montalvo did a 421 and used a 5.85 rod.

Just ah 1/8th" really does cause a lot more wear? well.... all I can say is "damn". And, I had my heart so set.

What about the guy in Houston whom is running a 412ci Impala using a 4.15 bore and 3.85 stroke. How in the hell do you pull that trick off?

Originally posted by Denny McLain
What about the guy in Houston whom is running a 412ci Impala using a 4.15 bore and 3.85 stroke. How in the hell do you pull that trick off? Start with a 400 block? :)

I get 416 CID with a 4.15" bore and 3.85" stroke, so it must be a 3.8" stroke if it's a 412 (411.2). That's an awfully big overbore if it's an LT1 block. :)

Mark tried two different combinations to end up with 421 CID. The first was a "big bore" (4.090" bore) with a 4" stroke (420.4 CID). His most recent 421 has a 4.125" stroke crankshaft, with a 4.030" bore (420.9 CID), I believe.

Coincidentally, it was the 409 LT1 built by TPIS and featured in the July '98 issue of Vette magazine that got me started thinking about a stroked LT1 for my project. The numbers (523 hp @ 5750 and 528 lb-ft. @ 4750) were what hooked me. Of course I sort of passed them by in both respects with less cubic inches, but that 409 was what started it all.

They used a 3.875" stroke crankshaft (with 5.85" rods) and a 4.100" bore (biggest I'd ever heard of for an LT1) to arrive at their 409 (409.3) CID, according to the article.

I hear what your saying about the 4.15 bore and a 400 block. My assumption is he is running a LT series engine because he talks about having a "hot" cam in the car. Actually he calls it a 409 and e-mailed me saying it was actually 412ci.. explaining the bore and stroke.

Jeez..... the more I know about these things, the dumber I seem to get.

Originally posted by Denny McLain

Jeez..... the more I know about these things, the dumber I seem to get.

thats just because there are so many combinations, cant really talk about a 409 like there is only one type, though what you have in mind sounds more common

so what are the limitations for bore on lt1/lt4 blocks? i'm trying to think if i ever even hear of 4.060" over the usual 4.03/4.04"

do LTx blocks from certain cars/years withstand higher bore? isnt it extremely rare one that will safely hold 4.06? how do you tell?

i really like LTx based engines merely on the fact that they are reverse cooled, think its a great starting point for a small block
but i thought they were limited to much less than 4.1" bore simply because there arent any reverse cooled 400 blocks

unless you enjoy never ending overheating issues and cracked cylinder walls, keep it below 4.050 :)

I cracked a block at 4.060, not to mention that puppy ranhot.

too bad nobody makes an aftermarket reverse cooled block that could go to 4.2" bore like the standard SBC blocks can :)

4.2" bore x 4" stroke lt1 would be real mean :) but 4" stroke on the standard deck height is obviously pushing it

Originally posted by Jimmy17
too bad nobody makes an aftermarket reverse cooled block that could go to 4.2" bore like the standard SBC blocks can :)In aluminum... :)

It will dissipate heat better... but... too high horsepower will not make the Al block to break? The cobra 03 has an Iron block instead of Al... although z06s are getting high horsepower on stock internals... and block widstanding 600rwhp +++ :confused:

Hope nobody minds my tossing a few ideas....

First, bigger is better in theory. In theory it's a good practice, but in practice it's only a good theory. I don't like big stroke motors for a lot of reasons that I won't bore you with. I understand the desire to build something different, and "409" sounds flashy for sure. For practical reasons though, you don't need anything radical to get where you want to go, and oddball stuff =$$$$ as you well know.

My thoughts are that a properly designed 383 blower combo is far more practical than a radical 409 NA.

I'm just thinking out loud here, but an LT1>SBC conversion might be in order. Something like a nice Little M set up at 4.185x3.875 with a 6" rod and a stand alone would be fun. I am putting together that engine right now with a set of Brodix 18* heads and a solid roller right now for an N20 application. Am hoping to locate a ChevyII over the winter for a nasty street car :cool:

Allright, I give up. I had something meaningful to contribute but am extremely hung over and can't think. Now that I've spent ten minutes trying to string together my thoughts I have to post it. Sincere apologies to all who just wasted two minutes reading this. :D

My first LT1 before going to the Gen 1 block was a 409. Wasn't my first choice but I had the crank from a previous order and it made a good home, albeit with alot of clearancing. After a bit of tuning preceeding a previous dyno run (488 rwhp) along with a new intake, the engine was probably in the 500 rwhp range. But that was about the limit I'd care to push a daily driver combination like that on stock 23º heads. The long stroke motors eat alot of the power in frictional and pumping losses so there's a limit. Because of this, pushing them to high rpm is usually counterproductive.
For your goal of 450 rwhp you should just stay with the 3.75-3.875 stroke combinations. A good cylinder head is imperative, but the combination of that, maximizing the tune and a mild solid roller will get you where you want to be without much problem. The RR AFR 215's are a good choice, even easier (and more streetable) with an 18º or 15º conversion though. All comes down to $ in the end.;)

Take care,
Chuck Riddeck
Progressive Race Engine Development

I appreciate everyone's thoughts and experiences. One thing is for sure......... I'm going back to a hydraulic cam. I just plain had too many bad experiences with lifter problems. Glad to hear other people are having good luck so I'll blame it on my grandfather and the family curse...... but, I've had a bunch of problems with solid rollers.

Thanks gang! OH....... what am I gonna do? Just keep it a 383 with killer heads and have fun for a change. Sure do like the sound of a 409 though.

Denny, why not save yourself some headache and prices of floor dry with the leaky LT1's and go LS1/6? more power.. more reliability and it is the motor of the future... it has been a while since we spoke.. this is Wes of Area 51 days... i do have my 6" 383 with LT4 heads from GTP that still makes 460 hp at the tire that i am interested in gettign rid of... i will make you a good deal on it.. if your interested let me know.. it has under 3K on it since it has sat since leaving Dallas and i have a Z06 now that runs 11.30's at 132MPH all stock with a NOS NOSzle system pilled at 175.... I have all receipts for my parts and would be willign to talk with you about it if you want to save some cash on putting together another LT1.... with the heads, all the machine work and high end parts you would have about 17K in my LT1 that you can get really reasonable...

Wes

whoa.. he is alive!

Wes

I heard you were living in Chicago. Glad to see you’re still alive and well. Still remember you building the engine you’ve got for sale.

Hey……..How’s that snow feeling hitting ya in the ass about right now? Dallas is pretty rough during the summer….. but compared to Chi Town in December, it looks pretty damn good at the moment.

I’ve mentally been though selling the 96 CE and getting a ZO6. It’s pretty impressive to see 390 rwhp with just intake, tuning and exhaust. AND….. it’s even got a warranty. Hell, heads and cam cars are getting 450 rwhp and look at what the 434’s are doing. No argument out of me that you can’t make them run.

Actually it’s pretty cheap to redo my current 383. All I need to do is freshen up the block, new cam, new heads and the car is where it should be. The heads may be fine in it now, but I just don’t trust the person whom did them or I wouldn’t even bother. Figured I’d look into doing a 409 while the engine is out of the car. Seems it’s not worth the effort, nor the effort to do another 396.

Course…. It ain’t over yet on buying a ZO6 either.

Good hearing from ya and good luck.

LOL.. yeah that is the price you pay for following the cash train.. the summers up here rock.. the street scene and crusing is a lot better than dallas.. the Texas boys still have the stuff to beat.. but all in all it isn't too bad up here.. i do want to get back to Texas one day though.. it sucks being a normal joe and having to pay for dyno time which i get for free at Norwoods on my old dyno.. few parts discounts.. but oh well i am making due. I had an 01 Carrera for a year and though that would satisfy me.. WRONG... even German engineering and panache could not satisfy the need for power... SO the Z06 is the new toy... LOVE IT!! this car ROCKS!! i am thrilled with the way it drives.... OFF THE SHOWROOM FLOOR!! add the spray and you can't ask for a better ride with a warranty!! i have a set of GTP LS6 heads and a cam i plan on putting in this winter but i am having a hard time bringing myself to do it... i don't want to go down the Camaro path.. money pit.. spitting parts.. you knwo the routine.. it is a reminder everyday in the garage.. if i could get a decent penny for it i would sell it but the LS1 cars are in high demand these days.. Good luck with your rebuild Denny and for what its worth i would run a 6" rod in the 383... it is too much rod in a 96 or 409.. not enough deck room withe the wrist pin height as well with the position of the pin in the cyl it creates HEAVY loading of the cyl wall on the power stroke... good luck and talking with y'all now that i am back in the right frame of mind and driving GM again!!


Jordan i see you have come a long way since the early days of Area 51... glad your doing so well and have a great name for yourself!! :cool:
Wes

I was the one whom grew up 120 miles from Chicago. Literally grew out of my diapers watching the 60’s muscle car wars between Chevy, Ford and Mopar. Absolutely killer racing (street and track racing) all through the area.

Hell, in high school; all there was to do was drink beer, race your buddies, do donuts in the snow and screw in the back seat. Something had to be good out of the four besides doing donuts. Sure wasn’t the Pabst Blue Ribbon or the women. Course the Pabst did make the Midwest women a bit better looking. Problem is the beer wore off. These Texas women are hard to beat and you know it.

Hey, on the 383 and 6” rods……… Man I’m keeping with the 5.7 rods for two reasons:

#1 under 6,500 rpm their just ain’t much difference. #2 their paid for. You and I both know how much money we’ve peed away on these LT1 cars trying to buy that magic bean. May be time to start getting smart for a change.

I’m changing professions leaving the medical industry and going with a large builder into real estate. If I can get away with driving a Z06, I may be with ya.

I thought also that 5.7" rod on a 383 made the most power too...

Although sideloading shouldn't bee much if kept under 6500 as you said..

Denny , I'm thinking of selling my motor and dropping in a LS1... Let me know if your interested...
sldrdave@globalserve.net

If you want to get the most out of a NA then the LS1 is the way to go... if not... if max powe is what you want.. you can do it better with a lt1... I think... puting in great internals and a big supercharger... it can be done.

I know this thread is pretty old/stale, but I ended up reading it because of a link from another and keep having the same recurring thought:

Problem with building an LT1, anything over 396 is that you either run out of deck height or reasonable/consistent cylinder wall thickness in a hurry. Seems to me if you want to do it right, I’d stay in the 4” and under stroke range and then have the block cut and sleeved so that you have perfect cylinder walls, a reverse cooling block and could run 400 sized pistons… With the sleeves you should end up with more mass for better cooling, and more consistent cylinder walls so that you get better sealing also. Yea, it’s a $$$ solution, but it’s one that will be more reliable in the long run and give you bragging rights WRT to ci…

Originally posted by WS6 TA
I know this thread is pretty old/stale, but I ended up reading it because of a link from another and keep having the same recurring thought:

Problem with building an LT1, anything over 396 is that you either run out of deck height or reasonable/consistent cylinder wall thickness in a hurry. Seems to me if you want to do it right, I’d stay in the 4” and under stroke range and then have the block cut and sleeved so that you have perfect cylinder walls, a reverse cooling block and could run 400 sized pistons… With the sleeves you should end up with more mass for better cooling, and more consistent cylinder walls so that you get better sealing also. Yea, it’s a $$$ solution, but it’s one that will be more reliable in the long run and give you bragging rights WRT to ci…

I am not sure that sleeves would help. The water jackets are only so far apart and the bore centers are fixed. Anyway, you aren't gaining much displacement from the bore - <2ci per 0.10" over. Anyway, if I wanted a high-po NA motor I'd go with the gen III architecture or maybe even gen I. Just IMHO.

Rich Krause

what are the things about LTx that make you prefer it for blown motor rich?

Originally posted by Jimmy17
what are the things about LTx that make you prefer it for blown motor rich?

It isn't so much that I prefer it as that the disadvantages aren't so important. Here's how I see it. If you are talking about a true max effort motor of any sort, you need a gen I. The strength of the Bowtie or aftermarket blocks can't be beat. And if you want to save 100lbs (at the cost of a few thousand $$$) you can get aluminum. There is a great choice of cylinder heads, etc.

For something less than max effort, if you want a great NA combo, the gen III architecture is the way to go. It's better than the gen II primarily because of the cylinder heads/intake and the aluminum block is nice as well. But for forced induction, the AFR's for the gen I are a good choice. And for use on pump gas, the reverse cooling is also a plus. I guess what I am saying is that the cylinder head advantage of the gen III is of less importance on a forced induction setup (short of max effort). Combine that with the fact that many of us already have a gen II, I see no reason to switch and some reasons to stay with it.

That's not to say that you can't have a dynamite NA gen II. Many on this board have them. And OTOH, I wouldn't go from a gen III to a gen II for any reason. Just that the gen II's primary disadvantage (cylinder heads/intake) are of relatively little import when you are talking forced induction.

Rich Krause

Personally... any high output street/strip engine effort (1.7 hp per cid or better) I want an aftermarket gen 1 block. More beef in all the important places and another thing that people seem to overlook..... better lubrication via priority-main oiling. I like n/a, so that means lots of revs.... and that means excellent oiling. Throw a Titan pump on there and you've got a bulletproof oiling system.

-Mindgame

Point being said... Money being an issue, is better to do a Supercharged on a 383 with 5.7" rods.

Being NA, I dont think the Gen II will ever cut it against the Gen III, there is much involved that I dont see the purpose.

I was going to do the swap but ended up the SC 383 route cause I think it is a lot cheaper and the engine can hold easy 500-600rwhp and still be a daily driver.

Reviving....

after seeing a guy that resleve its lt1 I was wondering if it was worth it to really do it.. My engine builder quoted me around 800 complete... He was going to check if it could be done or not...

I was thinking on doing a 4.125 bore x 3.85 stroke and have a 412CID if possible...

I guess that if the 383 is better for FI than the 350 then the 412 should yield a "similar" improvement???

Rich, my other question is.. you say AFR is a good head for Gen I. I was under the impression that the LT1 heads from AFR where a reverse cooled gen 1 AFR head... no difference... Hence the LT1 has a good choice.. and specially more for the adaptability of the 15º heads... I guess my other question is: is it that big of an improvement to go with a reverse cooled engine on the street on pump gas???

I told my engine builder to do it and i chickened out right now... i guess im not sure if it would yield good improvement on pump gas, which is my primary concern, over a Gen I block.

The sleeves can be done, they have been done... now... is it worth the trouble???

4.125 x 3.85 could yield a "rev happy" engine...

Highlander you have a blower combo..correct? Why would you want to go to that extreme with the big blower you have? What makes power is moving air, just pulley that dude down and make your own air. Sounds like brain damage to me using a blower with a sleeved block, did the machinist mention anything about running hot issues, much more sensitive with a blower IMO.

I have a buddy here close to me with a 331 cube mustang with a Procharger D2R that runs 5.70@127 in the 1/8 mile on 325/50 drag radials@3300 lbs, stock suspension.

Why do you need all those cubes with that big blower? Its gonna suck up all your boost.

And if you are building a NA application, its gonna be impossible to find ANY 23* head to feed that combo. You can build 550RWHP with a 18* headed plain ol 383.

Reverse cooling allows you to run more dynamic compression on pump gas

Just wondering, no flame intended.


David

Yes difference is that i can make more power on pump gas.. which is the sole idea of running that much cubes or looking for...

From what my machinist told me and from the work i saw... it looks pretty darn good.. so if there is enough wall clearance and it has been done already why not?

I just didn't want to follow through with the 4" stroke...

With a set of heads a la mindgame with more ccs and maybe more CFM and of course more money involved i figured you could make maybe 750rwhp out of pump gas which is hte sole idea... well... maybe...

I hope to be pushing around 670-700 on pump gas now...

if I did 607 with a smaller s-trim in a very inefficient range, smaller heads, less lift and NO coatings, i figure i could make that goal on pump gas.. and another 30 cubes with heads that flow 50-60 cfm more outa give me the 750-760 out of pump gas (with water injection).

A BIG bore,shorter stroke, short rod ,engine with real good heads and larger intake valve(big bore to cut down on valve shrouding) will make more power and torque below 7000RPM.Longer rods will do the same at higher RPM's.There is not a nickle's worth of difference in 5.7v6.0 rods in the real world.There may be some slight frictional loss and piston side loading but we aren't talking a 100,000 mile engine here.The ring pack is the main difference also wrist pin location.

With all that said, what do you guys beleive to be the best high mileage, STREET, bore and stroke combination with a supercharger? (centifigul of course)

if you really want to get milage, 355.

I build 383 generally, as people with cars that modified rarely put over 10-15k a year on their cars.

Here you go Denny. http://www.camaross.com/forums/showthread.php?s=&threadid=270141

410ci Wallah already done. ;)

Originally posted by T/A lt1
Here you go Denny. http://www.camaross.com/forums/showthread.php?s=&threadid=270141

410ci Wallah already done. ;)

That really blows too. Kid just got that engine all together.

Must have his eyes on a mean ride.:)

-Mindgame

Thanks for your input Jordon!:)