smallblock chevy crank stroke

[adrenalinejunkie76]

the tires are DOT aproved, ill have to check on the heads, maybe ill get lucky and they will fit, but from what youve said i guess they are probobly out of the picture, i was looking forward to using them, i guess im stuck with stock heads.

[adrenalinejunkie76]

i know this is an old thread but oh well, ive done me reacearch and found that the lt1 heads i got will bolt on my block, i just have to get a intake, i cant do a 427 without an aftermarket block, unless i bore out the motor i have now, wich isnt an option considering i already have pistons and cant afford new ones, nor an new block. according to the books that i have read, a 4.030 bore with a stroke of 3.75, and a rod length of 6.0 should fit into a stock block without much machining,and give me a 383ci motor. and im not going to go with a blower, looked at the #s of what a motor like myne can produce and decided its more than enough for a first car, epecaly the lightwieght one like the one that im building. am i correct on these specs?

[curtis73]

Yes, except I'm still not clear on the LT1 heads. If they are late model LT1 aluminum heads, they WILL NOT bolt on to a standard chevy small block. There are companies who make carburated manifolds to go on LT1 heads, but that should not be confused with compatibility with the rest of the small block.

I wish I could find pictures right now but I can't. The LT1 (92-97) shares many things in common with the old small block, but heads are not compatible. Its like putting a square peg in a round hole. The water passages are different, the head bolt holes are different, and the water jackets are designed with the reverse coolant flow in mind.

If you're talking about early iron LT-1 (different from the LT1 as noted by the "-" in the middle) heads, then they will work.

I've actually seen someone who grafted late model LT1 heads on an old small block. He welded shut the original coolant passages and drilled new ones, as well as drilled the proper bolt holes in the deck. In the end he had a small block that performed no better than stock. Why he did it was a mystery, especially since there are thousands of good performance stock and aftermarket heads available for the small block.

Otherwise, you have the recipe correct for a really nice 383. You've done your homework and decided to step up to 6" rods which is great. I hope it melts all the tires you can put on it

[adrenalinejunkie76]

ive looked at the heads and they will fit, dont ask me how, but they do. and no its the new style aluminum lt-1 heads not the older ones. and if someone did what your friend did, it doesnt matter, i would have been using stock heads in the first place, if nothing else it shaved 25 pounds off the front of the car and about the manifold, im not going with a carb im doing a efi setup. will a tpi manifold fit on lt1 heads?

[curtis73]

Friend, I'm telling you. They will NOT fit. They might bolt on, they might even look similar, but you'll leak coolant everywhere, your oil will drip right into the water jackets, and it will be a mess. They just won't fit. If you don't believe me, buy a set of head gaskets for a standard 350 and for an LT1. Lay them on top of each other and compare every hole.

A TPI won't fit on LT1 heads, either. Different bolt angles. If you're doing LT1 heads somehow, do the LT1 injection. Much more potential out of the box and 10 years newer technology.

I know it might look like they fit, but trust me, I'm talking from 15 years experience with small block chevys.

There are thousands of stock and aftermarket aluminum head choices for small blocks, so you don't need to worry about finding heads that work well.

If you want aluminum heads, look at the AFR 180 and AFR 195 for SBCs. Pricey, but worth the cash. Edelbrock aluminum heads are slightly cheaper but a slight step down in performance.