Ok, I was reading about the 265 4.3 LT1 crankshaft that is a 1 piece main seal and is a 3.00" stroke. I know it's a cast unit which is it's weakness, but was wondering about giving one of these a new home in an odd ball combo. We all know about the old school 302 67-69 Z28 motors.

Basically take a 265 crankshaft and put it in 4 bolt mains (or 2 bolt with splayed caps) 1 piece seal regular 350 (NOT LT1) block and use the correct length rods and 302 Chevy pistons. This is basically a "new school" 302 motor. This would be balanced and all and have good hardware and some cleanup work done to the crank.

I would think it would like to rev up good, only weakness would be the cast crank. Many people are making a lot of power on cast cranks. It would use a solid lifter cam (possibly roller) and an old school carb setup.

What do you think? Would this work? Any input? I don't know if it would ever come to be, but this is kinda a theory type thread.

(And yes I consider this advanced tech and don't think it belongs anywhere else. I'm sick of the repetitive BS stuff in the regular forums too)

Steve

 

but why? If you just want it to rev like no other, you can do that with a 355 or 383. Just get a really light rotating assy.

 

the piston speed would still be high

 

True. However, people rev their big cube LT1s all the time. How how are you going to rev?

 

Agree on 'how high do you want to rev'?

As far as piston speds go, if you use 4000 ft/min as a limit, which is probably ok, you have 8000 to play with, but if you use 5000, where Winston Cup and F1 engines are, you have 10,000 rpm available.

Cup engines run near 9500 rpm, but with strokes about 3.25. Fastest F1 engines are nearly double that with half the stroke, so the same piston speed. If you're going to play above 4000 ft/min regularly, you need to have deep pockets. If you are doing it to produce power, like a Winston Cup engine, you'll need a very strong lower end to handle the g-loads which kinda shorts out the cast crank.

My $.02

 

I just built a balanced and blueprinted L-99 (265 ci) motor for IHRA Stock Eliminator. It rev's much faster than the Lt-1's that I have built. Without fine tuning it made 304 rwhp and has run a 7.84 in testing (3300 lb Camaro). I feel that with a few changes it will pick up quite a bit more.
At Rockingham I wound it out thru the traps and it pulled to over 8000 rpm! (Stock crank, rods, and stock replacement pistons).
Why not try the L-99 as-is before sinking a bunch of money into building a 302?

Best Regards,

Daren

 

Hmm, well, How does this apply toward big blocks? At 6000 RPM a 454 piston is moving 4000ft/min. Those parts are relatively heavy compared to a small block.

 

I didn't say I was actaully gonna put this combo together, but was more curious on if it would actually work. Basically this is one big hypothetical situation on if and how well it would work. And other's input on it as well. Thinking about it more, it would be easier and cheaper to go with a better quality 383 or somthing of that nature. You all are right, if you build the bottom end you can rev the **** out of it and it wont break.

I was just kinda interested in the fact that it was a 3.00" stroke crank and how that would work. I have found out that I can get a forged aftermarket crank with a 3.00" stroke as well. No one uses a combo like this and goes bigger and makes the power that way..

When I do end up building another SBC eventually, it will probably be a stroker or a solid 350.

Keep the opinions and info coming though.
Steve

EDIT: WOW! GUMP I'm impressed....

 

People with 302 Fords pay a lot of money to stroke it out to 347 and you want to make it smaller?

 

I am not familiar enough with destroking engines, but I have known people that have done it. It will allow it to rev higher but I am not sure about what the hp numbers are.

I have heard, and not that sure about this, but I think the formula one cars are 2.4 liter motors. To me that sounds like they destroked it, I might be wrong on this. I read an article in Popular Mechanics that said they turn the 2.4 liter motors to 18,000rpms.

And I am just going to leave my engine at 302 cubic inches. I ain't in it to have the "fastest" car around, just in it for fun.

On a side note, me and my father put together a 347 for $1,200 that made 500+rwhp. We were able to do it that cheap because we did all the machine/engine work ourselves in the shop in our backyard. We saved a ton of money in labor costs. We sold the motor to a guy that runs a 300-500 shot of gas, he did change over to the A4 block. The stock block would have had no chance to hold up under that much power, when he was spraying the gas.

 

I'm a newbie to this but....
would'nt destroking the motor drastically drop the compression ratio?
Do you put a high compression piston in to try to make up for this?
I know in the late 60's early 70's keith black made destroked 360's for the dodge challenger / Cuda teams in the trans-am series.(this was probably to get below a max displacement limit) . The motors reved like there was no tommorow(7500) , this was probably perfect for road racing.

Anyway just some thoughts.

Great topic BTW

 

If you blueprint the L-99 to NHRA specs. using the factory pistons and head gaskets you end up with 10.7!

 

I beleive in a past issue of GMHTP, they had an LS1 that was destroked to 302, I believe the GM engineers did it just for the hell of it. I remember it saying that it made a decent amount of power.

 

If you want something you can rev the heck out of, and make a decent amount of power you can try for a Pro stock truck motor, I'm sure yall remember the NHRA truck class and the 358ci short deck motors they used. I'm not exactly sure of the crank or rod length but I believe they reved those to 10,000 rpms and ran the mid 7's.. Dunno how deep your pockets are though

 

OldS is wise in the ways of the piston and her movements.

Listen to him, IMO there's no reason to go shorter than 3.48" for what most guys want, b/c most are limited by the stock PCM fuel fuel/timing tables to 7k

Gump, I love stock eliminator! Man.. 3yrs at Jerico spent with a bunch of S/SS etc. guys was killer. 7600rpm with a heavy cast piston and itty bitty 283 rods? Sure, why not?

RicocheT,
You havent lived til you've stood at the line next to something like that leaving . Watching guys like jerry & roy hill run 7.1's at ~190mph away from you brings into focus just how quick these cars are