lavoy

iTrader: (2)

bought a 5.3 for my turbo build going for 700 wheel hp on pump gas and meth, tore the motor apart and it has flat top pistons so ran the part number on the crank and its a 4.8 , not sure if the salvage yard will take it back since i tore it apart so if they dont how will this affect my build, i know hot rod magazine ran into the same problem and made good power on a 4.8 but they didnt care if it blew up and as my daily driver and weekend racer i want to be sure.

getusumws6

iTrader: (9)

Have you called them to find out if they will exchange it? did you not look at the casting to make sure it was a 5.3 before you tore into it ?

redtan

iTrader: (5)

Are you replacing the crank and bottom end on this? Or are you just throwing boost on the current engine?

I say this because the 4.8 block is the same as the 5.3 just with a shorter stroke, so if you're building it up it won't matter anyway as you can just get the correct stroke for the displacement you want.

If you're just keeping the bottom end as it is, I doubt you'll have a problem getting the power levels you want, but idk how a higher compression cast internals engine would hold up at the boost levels needed for 700rwhp.

lavoy

iTrader: (2)

casting on the block is the same for a 4.8 and 5.3 they share the same block , that aside i ordered a 5.3 so its up to them to pull a 5.3 , and im leaving it stock, i tore the heads off to change the head gasket and put in arp studs and saw the flat pistons, the only way to tell a 4.8 from a 5.3 is the flat pistons vs the dished and the part number on the crank and the vin on the truck.

91sonomast

Hell I'd leave it be and continue on with your project. File the ring gaps and work your tune and boost up to 700hp

Paul Bell

iTrader: (9)

There's no replacement for displacement.

No doubt you can make the power with a turbo but if you keep it a 4.8, you'll always be wondering how much better it would be if you went with your originally planned 5.3.

I'd say as you're boosting, you should be looking for a forged crank anyway.

DMM

Chevy HP mag did a 5.3 twin turbo build to see how much it took to kill it, all they did was file the ring gap another .005"...it made 1200+ HP and blew out the spark from the factory truck coils at 27 psi. The editor noticed the flat top pistons in the pics and they tore it back down to confirm it was a 4.8.

Build the **** out of it and try to kill it...then do it again! You're fine. I will post the link when I get home.

Edit: My bad, it was the Hot Rod Mag build...http://www.hotrod.com/techarticles/h...g_bang_theory/

DMM

Oh...and they did over 60 pulls at 1200 HP before they ran out of time on the dyno.

lavoy

iTrader: (2)

i saw the article in hot rod that was pretty neat they did that. didnt know another mag did it to

Blk98Vert

iTrader: (2)

I'd prefer a 4.8 over a 5.3 for a turbo build

bww3588

iTrader: (49)

I agree... And like mentioned above, your getting close to wanting a forged rotating assembley (to be safe and make it last) so at that point you will have atleast a 5.3

I say slap the boost to it and see what it does...then hit her with some better internals and really crank it up.

garygnu

add more boost and spin it higher.sounds like a great project.

chrisfrost

iTrader: (8)

You tube someone boosted a 5.3L to 24lbs. and was showing 2000hp on the dyno ,,,,,,,,,,,,the 4.8L is just as tough if not tougher ,,,,,,,course You could'nt boost that much and expect it to last ,,,,,,,,,,,,but I would say yes 700 at the wheels would be pushin it a little but if You kept the rpm's under 6500 You should be able to keep it together for a while .

ryle

iTrader: (19)

**Dammit... DMM beat me to it...**


http://www.hotrod.com/techarticles/h...g_bang_theory/

This is the above referenced Hot Rod Magazine article. Twin turbo setup on a stock bottom end produced 1200HP+.

aQuickLS1

iTrader: (7)

There are some turbo 4.8l trucks running 10's in the 1/4 on the truck forum... with a stock bottom end. So I think 700rwhp is achievable.

pwrtrip75

iTrader: (8)

4.8 vs a 5.3 ... set up right you probably wouldnt notice the difference. Small cubes are not a bad thing at all.