rkreigh

I have a nice forged rotating assembly for an ls1 but I'd like to run the stronger block with a goal of about 900 to the wheels on E85 with a ttix turbo car

I've seen various opinions and boring the block .120 has me a little nervous on getting the block walls too thin to support this power level

I have a nice set of AFR 225 heads

mostly a street car but I will be beating on it at the track a few times a year and turning up the boost to get the RWHP I need to run 9s

I've got a lunati 4.0 crank rods, and wiseco pistons

if boring that much won't work, will a smaller bore size work OK with the AFR 225 LS1 heads? I like the the heads and can always use the LS6 alum block if needed. the 3.905 seems to be a "max size" for either block and only recommended for normally aspirated engines

thoughts??

dezlfrek

iTrader: (1)

mine is l33 block, 3.830 bore with stock 4.8 crank for 302 cu in, runs 9.7x at 139 on low boost(14psi) on e85 at 3400lbs..
has run 9.5x@ 148 on higher boost..
but i run 243 heads too..
so long story short will it run 9's.. im sure it can.. I have no idea about the rest..

gaskill

Think about bigger pistons? Keep everything else and use iron 6.0 block.

rkreigh

will the small bore afs 225 heads work on a 4.0 inch bore block?

I think I can bore the 4.8 block pretty safely to the stock LS1 size if I buy new pistons.

just trying to use what I have alredy which is 3.905 which looks like the biggest size to hone the ls6 out too.

I agree that keeping more meat in the block would work best for strength and and new pistons aren't that much

JAX04

iTrader: (17)

my next motor....

4.8 crank... 4.030 bore....

slowbu

iTrader: (4)

just have the machine shop sonic test the block first
bout 90% of the 4.8/5.3 blocks will do .120 over no problems
there is a few guys on here with iron block based ls1's boosted well over 700whp without problems

can't recall the dudes screen name atm
but he has a forged bottomend iron ls1 in a red rcsb truck pushing right at 1000whp