david_351

Hey Guys, when building a 396 its my understanding that you need to bore 40 thou over. When boring this much, to what extent does the whole water jacket issue come into play? Any ppl here running an LT1 bored 40 thou over or more, input would be appreciated. I have heard LT1s dont like being overbored much more then 30 thou, can anyone here confirm that? according to one of the books I have the LT1 can safely be bored out as much as 60 thou, but Ive heard mixed opinions on this. Thanks in advance for your help
David

IllusionalTA

iTrader: (9)

4.030 bore 3.875 stroke =396c.i

Abdullah

iTrader: (2)

i think you can over bore the LT1 block to 60 but you might need to sonic test the block.

40 over bore is safe. with 40 over bore you get 398ci which is
= 3.875" stroke X 4.040" bore

30 over bore will get you 396 ci = 3.875" X 4.030" bore.

60 over bore will get you 401ci = 3.875" stroke X 4.060" bore.

ckyconan2003

iTrader: (2)

what about 402??!?!?!?!?!!! lol

Abdullah

iTrader: (2)

it could be 0.075" over bore with 3.875" stroke but i think you will run into the water jackets that way so i think the maximum possible over bore in a LT1block is 0.060".

socal

iTrader: (1)

mine was built .40 over. it's just like a sbc you dont wont to go past .60.

97blkz

iTrader: (1)

I've had my 396 for 3 years now without an issue.

Karl Ellwein

Most builders keep the overbore to .030 and with the 3.875" stroke crank you really get a 395.4 ci (almost a 396). Most everyone calls it a 396 so why buck with tradition.

If you go .040" over with the 3.875" crank it will be 397.4 ci

If you go .060" over it is a 401.3

A 4.000" stroke crank and .030" over piston is 408 ci which many call (409) and heck why not call it a 409...nothing wrong with that.


Karl Ellwein