I have a 2002 4.8 that is for sale here on the boards that I might keep for my truck if no one buys it. It has corvette 241 heads on it. What is the stock compression ratio on the 4.8's and the head chamber size, the 5.7 heads should drop compression a little bit. Need to look up their size too if anyone has the info on hand would be great. Was looking at the other how much power thread for a 4.8, how much can they hold. If built like a stock LS1 should handle a decent amount. It's low milage and in awesome shape. Was thinking 8-10psi with a Thunderracing cam, springs, etc. Might do a single 60-1. Maybe a 66mm. Just turn the truck manifolds forward and mount the turbo up front. Already have an intercooler design setup for it. Think I could get 400rwhp, maybe a bit more, out of it?

 

My 4.8 on 9psi with a 60-1 and FMIC made 330rwhp, you could get a lot more power from it if you used the block and switched it to a 5.3

 

Was it stock cam and everything? I would think 12psi would make close to 400 with cam etc. But maybe I'm wrong.

 

yep, stock everything.

 

Not bad, with a cam, tuning and a little more boost I think I could get 400rwhp out of it.

 

i hit 496rwhp in a complety stock 4.8 on a mustang dyno. it didn't even have valve springs. this was around 20psi. this was with a cut out, good fuel and a t76.

it would have gone higher but i was running into wheel slip and valve float. dont let it knock and it will hold a lot of power.

 

Hell ya thanks Parish, think you could give me a few tips on keeping it good on pump gas? Maybe throw race gas at the track. My email is DalZ24@aol.com, your like the walking LS truck engine god haha

 

keep your a/f around 11.5-1, somewhere in the 15-18deg of timing and as much boost as you can run before you start seeing KR. then back it off 1 psi or so. thats still prety close to the edge so you will want to keep an eye on the scan tool especialy when you make full 1/4mile runs.

with race fuel it is about the same. a couple deg more timing and then turn it up till you start to see knock then back it off a little.

always listen for knock too. if you hear it and ignor it you will blow it up quickly.

 

Did you run head studs or anything special or a completely stock motor? I'm planning on a small cam change (like the TR reverse pattern FI cam), head studs. so around 15-18deg of timing at full boost? and 11.5:1 sounds pretty rich to keep safe, stock injectors lol? Thanks alot for the info, I'm debating on running a single T70 or maybe 2 50 trims.

 

you will need biger injectors for almost any amount of boost. real big if you want to push it hard.

the stock fuel pump will take you to maybe 5psi. a good aux inline will probably take you as far as you will be able to go with a stock 4.8.

in my opinion all you need is valve springs to go 500+rwhp with a 4.8. that and dead on tuning. that means watching your tune, not just set it and forget it.