88rx7v8

iTrader: (1)

as the title say, i got a lq4 6.0l that im getting it bored 0.030 over to make a 6.2l (408ci).... i was thinking of using some 241 heads to raise the compression. Is the 241 heads gonna give problems or should i use the 317????

King Nothing

iTrader: (9)

i'd think you'd want to go with a 317

PowerShift408

iTrader: (44)

My car was like this once upon a time. No problems.

Also, a 408 is 6.67 liters. You have to use a 4'' stroke crank in conjunction with that 4.030'' bore to get 408 cubes.

6.2 = 376 cubes a la LS3 displacement.

DTB_LS1

iTrader: (2)

Check out ndfrsd6. He put down over 500rwhp with his 402 using ported 241s.

88rx7v8

iTrader: (1)

i stand correct! but doesnt the lq4 already have a 4inch stroke crank from the factory??

88rx7v8

iTrader: (1)

dtbls1 thats some nice numbers!!! i imgaine that kind of power on a 2800lb car

LS1-NAVY

iTrader: (1)

no it has a 4" bore

tspence45

iTrader: (30)

Nope. Same 3.622" stroke as the LS1.

02*C5

iTrader: (1)

Why would you want to restrict the air flow to your engine like that. Either 243s or 317 but not 241s my .02

King Nothing

iTrader: (9)

thats what i was thinking but also just my opinion

the_merv

iTrader: (88)

Here are some numbers for you..

6.0l - 364ci
6.1l - 370ci (6.0l bored .030 over, that is what you will have..)
6.2l - 377ci (.065 Bore, stock L92/LS3)
6.7l - 408ci (.030 Bore, 4.000 Stroke Crank)


As far as the Heads, I would go with a set of 317's or 243's like mentioned..you will choke it with a set of 241's, unless they are ported.

1slowfbody

so building a 383 would take a 4.000 stroke crank?

mark21742

If you already have the 241s port them or run them the way they are and save up for a set of AFRs or Trickflows
That's what I'm doing, running my original 241s ported/ milled on my 404 til probably next year when I can get a good set of heads

01ssreda4

iTrader: (96)

I was under the impression that 241s and 317s were basically the same head except smaller and bigger combustion chambers respectively.

the_merv

iTrader: (88)

Yes, and I believe it's a different piston..3.905 instead of the stock 3.89..something like that.

outkast6991

iTrader: (34)

243's,799's, and 317's are all roughly the same port/runner and chamber. the 317's just have a bigger chamber(just under 72cc) compared to the 243/799(64cc)

outkast6991

iTrader: (34)

what kind of compession are you trying to get to?

88rx7v8

iTrader: (1)

that was my other plan run with 241 and my 317 have them milled,ported and angle valve job......

88rx7v8

iTrader: (1)

i was hoping around 10.5 to 11 cr

88rx7v8

iTrader: (1)

i appreciate all the help from you guys,im kind new to the v8......i got tire of working with 4cyl......