What makes a 388? A 400 crank and .30 bore? I have a good offer on an all forged 388 LT1 shortblock with a teflon coated crankshaft.

 

A 3.75" stroke combined with a 4.060" bore (.060" over) will give you a 388.

 

K well, fresh prepped block 2 bolt main with new rings bearings, all forged eagle/scat internals, SRP forged pistons. 1500.. I just looked at it yesterday, about to buy it.

 

i ran 3.75 rods and a .060 over bore and figured it out to be a 385. how could i get different numbers. if were essentially running the same thing. unless the builder didnt put the right rods in lol that couldve been it. but yea

 

A 385 is a 3.75" Stroke with a 4.040" Bore. Rods don't affect cubic-inch displacement.

 

so then the bore for mine was only bored over .050? and thanks for the help man

 

Thanks for the info Stealth. I am definitly going to get this block, he is throwing in a bunch of other go fast parts, 1.6 7/16 comp cams roller rockers, a cam.. not sure on specs tho, new lifters and pushrods and a 6qrt moser oil pan for 300 more. Cannot beat that offer.

 

Here's a calculator that's real helpful:

http://www.wallaceracing.com/cid.php

Well if you have a 388 then it was bored .060" over, 385 would be .040" over. .050" over would be a 386 and of course .030" over making a 383.

 

How bad is .60 over? That I wanted to give this motor a little bit of nitrous but may not because of the thinner walls

 

I wouldn't recommend any kind of forced induction with cylinder walls that thin. Many people say going beyond a 4.040" bore in an LT1 is a bad idea while others have done so and ran ok N/A. I have no personal experience running an LT1 .060" over so I don't want to speak on behalf of not having hands on experience with that.

 

Good link. Alot of really good conversion calculators there.

 

thanks man i saved that to my favorites. thanks for the clearification and everything.

 

Another way to make 388ci is 4.030" bore with a 3.80" stroke. You can get a 3.80" crank from Cola, or GMPP

 

an lt1 block needs to be sonic checked to bore .060 over. i have a 388 and will spray 300 on it, cylinder wall thickness not really an issue

 

make sure the guy has receipts of some kind for the internals

 

Yea he does not have receipts, really good friend so I will take his word, he builds lots of motors, internals look good the block was apart when i went to look at it. Eagle 4340 crank teflon coated, how much does teflon coating help? the damn crank looks green! Scat rods (not sure if 5.7 or 6) and SRP pistons all forged. Looks pretty good, internals are fresh! Well give more details soon, i will probably be starting a build thread soon for over the winter. Im ready to go fast