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What is the biggest possible displacement on a stock lt1 block???
We want to build a LT1-stroker for my friends 64īBel Air.
He loves the stroked SBCīs and so he have got the idea to buy a complete 350SBC/4l60-combo with all the the harnesses/computer and what you have, from another friend of us.
Than to remove it and stroke the hell out of it .
We found a company with quite cheap stroker kits (I know, a cheap kit is not as durable and strong as a better one but it is only a car for summer evening and will never see a race track) from 383cid over 396cid, 400cid, 406cid, 408cid, 410cid, 412cid, 421cid, 427cid, 434cid, 440cid, 447cid to 454cid.
The queston is:
What is the biggest displacement we can sqeeze in a stock lt1-block and where is the limit for the EFI-System?
I believe most people don't go bigger than 396 CI because of rod clearance issues. There are people that have run slightly bigger, but they have thousands invested in block work to get that displacment. You mentioned it won't be a track car but people are running 10 and 11 second timeslips safely with a 383.
The stock fuel system with the racetronix kit which uses a whalbro pump is good for 500+ horsepower.
I see you point, on the other side we have seen people running better times with smaller engines, but they have investet 1000s of dollars too to get that
I think the cheapest way for performance is displacement.
As for the rod clearence, what is to do? I think the only thing you can do is to trimm the iron of the block in the critical eara, right?
Why should it be that expensive?
There are a few issues......
1. quality 4" stroker cranks with the 1pc rear main are not readily avalible.
2. rods WILL contact the pan rain, so it needs to be clearanced......and you may open a water jacket because of core shift.....so you need to short fill the block.
3. you "may" be able to go .060 over on the bore, but you better staying safe with a .030 over job.
4. Having a 4" stroke crank means a 6" rod. That equates to a REALLY short piston. Fine for a race motor that doesn't run for extended periods of time, but may cause piston slap in a driver. There are ways around this though.....check the aug. 09 issue of car craft mag, they have a really insightful build that'll give you an idea of what I mean.
So safely about the best you can get is 408, most will say 396 since that is a common thing that's done now. It used to be that 383 was the biggest you could go.............now look at us....
But the 383 kit is is nearly as much as a, lets say 396 or 408, I still can earn the money in the heads and valve train and go with the bigger displacement tough.
A 396 will be more expensive, and a 408 even more so. Machining costs add up, custom small base-circle cam, block fill, pan rail machining, etc., all need to be considered. Truth is, a 383 will meet or exceed most people's goals 99% of the time.
But if you have money to burn, go for the bigger displacement. You may want to talk to a few machine shops/engine builders and see what they can do for you.
IMO, my setup is a good indication of what a mild 383 LT1 stroker can do.
__________________ 95 T/A AI 200cc stock castings, 383, Performabuilt 4L60E, Ford 9", Tuned by PCMforless 3340#, 10.81 @ 124.16, 1.43 60'Video of 10-second pass455whp, 445tq - Dyno Vid