bigfatls6

iTrader: (34)

I have a really low mileage 6.0 iron short block that is basiclly complete. You can still see the cross hatching in the cylinders. It turns over freely and all looks good on it. I am thinking about just installing new bearings and some good rodbolts. What horse power shot of Nitrous will the stock 6.0 pistons hold safely? Right now I have the stock ls1 short block in my car with a set of stage 2.5 patriot ls1 heads with the 2.05 valves and a torquer v.3 cam and 78mm fast intake and the car makes 400 rwhp and 378 rwtq with an a4 and yank pt3800 converter. I am thinking about doing a custom cam in the 6.0 and re-using my same heads. I know the 6.0 should make more torque but what about horse power?
Also what options do I have if I decide to buy pistons and rods as far as cubic inches? I know if you just bore 30 over it will be a 370 ci. What about different rod length with stock crank?
Also what compression will the 6.0 make with the stock pistons and a set of 99 ls1 heads. I don't think they milled the heads when they did the stage 2.5 port job and changed the valves. If they did it wasn't much. If I need to to get the compression up I can go ahead and get the heads milled while I have it apart.

Thanks for any help you guys can offer.

87silverbullet

iTrader: (11)

Well if you plan on doing a custom cam your power will change and that will depend on the cam you choose. With the bigger bore you can see a lil more hp than you you ls1. With an a4 470 rwhp is very attainable. Rod length has no bearing on cubic inches. I could put a four foot rod on a 3.5 inch stroke crank it still only moves 3.5 inches. If I am right but I think I would have to get some other guys to chime here but you comp. ratio should be 10.4:1. Just an idea Livernois made 520 flywheel hp with there stg 2 cam and stg1 heads and this was a good while back on an ls2 stock 6.0 bottom half. Good luck on your build.

bigfatls6

iTrader: (34)

When i had my car dyno tuned with the current set up they did some calculation by figureing the percentage of horse power lost through the drive train and figured out my current combination made real close to 500 hp at the crank. The only time I had the car at the track it was an 1/8 mile track and it was on regular sumitumo street tires. I found out quick that I had to leave at Idle on the street tires but the car 60 ft was a 1.77 1/8 mile time was 7.65 at 92 mph. I am sure if It were on tires and leaving with more rpm it would have easily gone into the 7.40s.
I guess the heads I have along with the cam is a pretty good combination. I still want to go to a custom cam in the 6.0 but I would like to re-use the heads I have. I guess I need to find some one to spec me a cam shaft.

87silverbullet

iTrader: (11)

I am assuming you want something drivable like your v3 cam? If that is the case, with the bigger cubes you might want to go to something like lower 240 on the intake and upper 240 on the exhaust to keep it civil enough to drive around. Get it ground on a 114 if you want to spray on it. It will pick up more power on the spray and it will idle a little better. Your heads should be fine for it. It should be an animal for you. Put it together and show us some track times and dyno graphs.

NemeSS

iTrader: (127)

i have sprayed 175 wtshot on stock 6.0 bottom end before
what cc chamber of your heads? which heads are u using?
lmk the chamber and i can tell u how much compresion or amount to mill
if need specific compression,
lq4 has 8cc dish, 4.045 bore with .055 compressed thickness for 6.0 gasket
.008 out of the bore,

bigfatls6

iTrader: (34)

I am thinking the heads have 63cc chambers. They are what ever cc a stock 99 ls1 head is.
What you been up to carlos?

NemeSS

iTrader: (127)

the stock cc for ls1 heads is 66
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