A friend of mine just purchased a used 1995 383 LT1. It is supposed to have an aftermarked non-forged 383 crank, stock rods, and forged pistons.

We are in the process of taking it apart to replace the bearings and the rings and convert it to a 4 bolt.

I noticed that there is no clearancing done on the block for the rod bolts. When I built my forged 383, I had to clearance the block or the rod bolts would hit.

We have yet to measure if the crank is 3.75", or measure the total piston movement to see if it is a 383.

Until I we have time to do that, I thought I'd ask:

Do some 383 LT1 configurations require NO clearancing?

Thanks.

 

nope, all require clearancing of some sort

 

I am guessin' it's not a 3.75" stroke.

Rich

 

If you use the short 400 rods, 5.565" length, don't you avoid block and cam clearance issues? I realize the short rods are undesirable because of side loads, but in most street applications it probably doesn't matter.

Also wouldn't the early 60's small journal rods clear the cam and block if you turned down the crank?

Thirdly, do any of the aftermarket rods designed for clearance with a stroker crank eliminate the need to notch the block or grind the bolts?

Lastly, what does GM do on the factory 383 Goodwrench engine?

 

If you use the short 400 rods, 5.565" length, don't you avoid block and cam clearance issues? I realize the short rods are undesirable because of side loads, but in most street applications it probably doesn't matter.

Length of the rod has nothing to do with it. It's thebig end of the rod that is the problem.

Also wouldn't the early 60's small journal rods clear the cam and block if you turned down the crank?

Yes. But that would be a 2-piece rear main crank. Of course, it could be a turned down 1-piece I suppose. That's a lot of work and compromise to avoid a little work and no compromise though.

Thirdly, do any of the aftermarket rods designed for clearance with a stroker crank eliminate the need to notch the block or grind the bolts?

They can make less clearancing necessary, but I never seen a set that didn't need some clearance.

Lastly, what does GM do on the factory 383 Goodwrench engine?

Good question. I never looked at one. My guess is that they clearance the block as on most big blocks.

Rich

 

Well, we confirmed tonight that the stroke was indeed 3.75". It is using stock lt1 rods and a scat crank. Interestingly enough, they clearanced the rod a tiny bit. I can't imagine why someone would do that instead of the block. I would consider removing material from the rods way more critical than the block.

So, we just tore apart proof that a 383 can be built without clearancing the block!

 

Can someone post pictures of the clearancing done on a 383 LT1 block? I am in the process of building one and would like to see what it looks like done.

 

Ttt