i was just wondering if anyone here was running one of these i was thinking about running one of these in my next lt1 build.
any insight would be appreciated

 

You will probably have a nearly impossible time getting it to clear.

 

try this link: https://www.camaroz28.com/forums/sho...ght=block+fill

 

While it may, or may not be possible (I dont know, never read greenmachines link either) most will agree after so much, its just not worth it anymore. However, if you want to do it, thats up to you.

 

It would be helpful if you listed your goals and budget for this build. Chances are good that a 383 or even 396 will meet them just fine without all the work necessary to shoehorning a 4" stroke crank in.

It can/has been done but it's never easy and doing it the right way is expensive when you consider the "gains". I'd just go to a generation 1 block (or LSx) if you want 400+ cid.

 

Agree with the above post, but hopefully someone can give you the info you need. I agree that the project would have an unfavorable cost/benefit ratio.

Rich

 

this is true. i am going to do a 396 instead

 

There are a few running around, real nice setups.
A search should bring a few up.

The CID and Stroke don't necessarily make up HUGE amounts of power, but they
do allow the use of more aggressive camshafts. I think it's more stroke and clearancing than you
really want to expose an LT1 block to, but that's just me. It ain't cheap, but it is different, which is kinda cool.

 

A 396 is pushing it, too. The extra 13 cubes are just not worth the aggravation and possible coolant leaks into the oil. I'm willing to be that with two equally prepped motors with the same hardware, one being a 383 and one being a 396, there wouldn't be a gnats whisker of difference in performance. Meanwhile, the 383 is a lot less of a headache to build and a *lot* less likely to break into the cooling jacket while grinding clearance.

I think guys get too hung up on cubes and/or bragging rights of saying 'I have a 396!'.

 

So much for the old adage of ...."There's NO replacement for displacement!" ....eh?

 

Well there WOULD be a difference... the 396 would peak tq/hp lower than the 383. Seen it. good for about 500rpms drop.

 

sheesh...

there have been several successful 4" stroke LT1s built over the years. There have been even more successful 4" stroke Gen1 engines built over the years.

If you are stuck using a stock PCM with only a 7200RPM limit, then there is even more of a reason to go with a larger engine.

Go for it!

 

Gen 1 strokers are easy; there are aftermarket blocks available.

And while there have been sucessful 4" stroker LT1 motors, I'd say it's not a good option for someone who cannot afford to watch a motor blow because a real thin spot ground for clearance failed and happened to let a gallon of coolant into the motor. I also feel that filled blocks, even half-filled, do not fit in the realm of 'daily driver'. I really don't care what the latest magazine says, or who on here claims they're doing it. See the bottom of my post for why.

If the car is a toy, and you can afford to lose a motor that you built out on the raggedy edge... Then go for it. If the idea of spending a metric butt-load of cash on a short block that may or may not leak coolant into your oil, most likely while you are driving and eating your investment... Well, then the raggedy edge isn't for you. Like the saying goes: The best way to make a small fortune racing is to start with a large one.

As far as the 7200 RPM limit... It's not a hard limit and the motor can't spin past that. The factory tables just don't have any cells in that territory so you get stuck with the last cell's parameters. That's not street car/daily driver/weekend cruiser territory in any sense, regardless. If you're spinning that kind of RPM you need an aftermarket computer... And at this point you're driving a race car. I personally think guys build too much damn motor for a street car, with the biggest heads/cam/etc. All for what, bragging rights? I saw this all the time at the speed shop I used to work in. Some guy spends all kinds of money on the biggest parts, ends up with a temperamental, short-lived headache of a motor and a project car that they don't like quite so much any more... Especially when they seem to spend every weekend and/or night wrenching on it instead of cruising, or they got their doors blown clear off by a more conservative build that actually works right because the owner didn't blow the budget on the coolest billet gadget of the week and spent his money on lesser parts that actually work well together.

And I'd like to direct you all to the quote at the bottom of AdioSS's post:

Keep in mind, bench racing/theoretical engine building is the biggest Internet Car Forum pass-time. Keep in mind that some the the people here have no practical, hands-on experience with actual engine building and they're trying to give you advice like they do!

 

True, which is why I went with a 396 over a 383 or 355.

The issue with a 4" crank however is the air flow needed to supply displacements that large jsut won't go through a LT1 head casting without boost. Forget a "stage III" port job, my LT1 heads had that and more (replaced valve seats, large valves, heavy intake port). The truth of the matter is that outside of hogging out the runners even more than they are would be close to impossible IMO... i already have severe valve-guide exposure on the runners and very narrow pushrod clearance in spots. Without using offset rockers and moving the pushrod pinch point (and requiring a custom intake) or just tossing out the LT1 stuff altogether and converting a set of 18* (or other exotic) heads with a custom intake and headers... you won't see any more hp gains n/a. (and the 396 is plenty large enough to eat up even a GM847 cam with 1.6 RR's).

I haven't worked with any of the monster AFR castings, but there are a) costly, and b) still require port work for a max-effort build like this would be (read +$2000). Doable, but not cheap.

If you're going with a 4" crank to keep the RPMS lower than a 396 would be... you better had some serious heads and cam to go with it. Solid roller is a must. Custom intake, headers, and converted exotic heads is a must. Without heads under $5000 available the extra displacement above a 396 seems like more trouble than it's worth.

Sure you could use LT1 heads and slap-on a blower to force a decent amount of air flow in to feed a huge displacement like that but then you're REALLY getting pricey and have SERIOUS concerns about durability unless the boost is kept low (which seems like a waste of cash considering).

If you have some SB2 or 18* Brodix heads "laying around" and you know a guy who can weld/drill them to fit the LT1... have at it. Otherwise, you're just flushing money down the drain... a 396 is more than enough displacement for LT1 architecture.

Adding to the mess is the drivability and tuning of an engine with a cam and air flow that large when it exists at minimal throttle and rpm for 99% of its life. A hydralic-roller 396 with a nitrous kit would likely be easier to drive, have the same hp, and WAY less expensive than a 4" monster.

But that's just my experience... YMMV.