What's the shortest stoke you guys know of for the LT1?

What I would need mathematically is a 2.425" crank, but I'm pretty sure that nobody makes one that short. Also that's assuming that I wouldn't have to overbore at all, which with a 120k block is unlikely to say the least.

I think that 4.0 L is probably out of the question, but I figured I'd at least ask.

Thanks, Chris

 

Why are you going with small stroke. You can run a 4" stroke to 7000rpm all day long, and after that, you need a new PCM for the LT1.

 

Autocross rules. The class I want to compete in has displacement limits.

 

saw some dude w/ a 351 LT1 yesterday..smallest ive seen

 

Smaller stroke=lots of HP

Long stroke=Lots of torque




They made a 265 and a 350 version too.

 

And lots of torque = lots of power.

 

You'll be limited on your choice of cranks that have less than 3.48" of stroke due to the one piece rear main seal. If you can run an adapter, you can run an older two piece crank and run a 3.00" stroke for a 302 ci LT1.

 

Sounds like a pretty stupid rule and very unfair to a larger displacement, low rpm spinning motor.

I would personally just say **** it and do something else vs having to make a smaller engine, which requires a lot of coin.

But if I was set to compete and it required a smaller engine, I would look at shorter stroke and smaller bore size. Maybe it would offset the high rpm need that you will have to attain to get a lot of power out of the combo.

Or to destroke and long rod it. Then get aftermarket SFI unit and shift at 9000 rpm or just put a carb, distributor and 700R4.

What I am curious about is what are the other vehicles weights compared to the engine size. Let's say you can get your combo down to 300" but are still weighing in at near stock weight and someone is at the 300" but weighs 2700 lbs...you are going to have to make some serious power to make up for that, not to mention braking, handling..etc...that whole picture would basically make it very hard to compete in a class like that.

IMO

 

Well, the displacement limit is only 4.0L under forced induction. I'll probably just run N/A, and do a 355. It seems like it would cost so much to get down to 244 inches that it would be a total waste of money. I'm not really down with spending the coin on an entirely custom rotating assembly. Oh well, bye bye blower.

Thanks for the replies, guys!

- Chris

 

I'm not saying go ahead and cheat and sneak it, but how do they know what you have in there?

 

It's very easy to do a displacement test.