96prplz28

iTrader: (14)

I got some ported and polished 6.0L heads with bigger valves from my buddy. I have a stock bottom end 346 with a 232/234 cam. I know that these heads are a little big for my car. Speed INC said these heads on a 346 would lower my compression to about 9.1 and that it would run like *** N/A. Is the compression to low to spray nitrous? Should i put the heads on or not? Thanks

sroach20

iTrader: (31)

good for boost but not nitrous.

PREDATOR-Z

What is the chamber size ??

SIC LSX

iTrader: (10)

good for boost! I would waste my time doing that swap! Just sell them and get some 5.3 or ls6 heads

PREDATOR-Z

You guys are jumping the gun, what is his chamber size?? They are allready ported, perhaps the are welded 6.0s with smaller chamber (Like PP LS6 style), those are 6.0 castings.

TA2SLOW346

iTrader: (3)

If those are my old heads they are 67ccs

PREDATOR-Z

If these are milled 71cc heads then PTV should be measured for that cam. That is like ~ 4cc mill or .025

The 232/234 if on 113 "should" clear and if 112/112+2 or 112+4 better measure on intake side just to be sure.

96prplz28

iTrader: (14)

Yes they are your old old heads. So would i be fine swapping them since they are 67cc or would it lower the compression to much? The cam is the Torquer 2 i was going to go with the 112 but should i go with the 113 instead. So these heads are milled -4 degrees?
Thanks for all the help

Mike94ZLT1

iTrader: (3)

If a 6.0 liter has a 4" bore and you can put 6.0 heads on an LS1 with a 3.9" bore, why can't you put L92 heads on?

PREDATOR-Z

You wouldn't realy loose any compression. Stock heads are 66.67 and this one 67cc so very minor loss.

I would pick a cam that can fit with a tight LSA to maximize your DCR.
Like a 227/230 .629/.612 112+2 (LSK/XFI) lobes from Comp cam (Custom order)

PBMFIsMe

iTrader: (5)

I believe part of the reason is because the intake ports are a different style and require a different intake manifold.

As for the actual size of the bore, not sure.

96prplz28

iTrader: (14)

Yes the Intake ports are totally different style.

TA2SLOW346

iTrader: (3)

Heads where milled .040 but the sides of the chambers where opened up to fit a 4.100 bore that i use to run.

TA2SLOW346

iTrader: (3)

BTW i made 387rwhp with those heads on a stock bottom end thru a unlocked A4 and mac headers, borla catback, ls6 intake, untuned.

PREDATOR-Z

.040 should put the chamber at less than 67 cc.
Let us say ported 72cc unmilled.
.006/ 1cc >>>>> .040/.006= 6.7cc

So they should be 65.5cc

96prplz28

iTrader: (14)

So they will be perfect. I am going to go with the Torquer 2 cam on a 114

PREDATOR-Z

Be aware that you might need to flycut for so much mill (.040 means .040 loss in PTV Vs stock motor)

TA2SLOW346

iTrader: (3)

Dont know if you over read this or not.

PREDATOR-Z

So you had them measured at 67cc?
either way .040 mill, better measure PTV in a 230 range intake duration cam

TA2SLOW346

iTrader: (3)

Nope i measured them when i ported the heads back in 2001