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?

 

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/showt...hreadid=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!