all you need to do to the 5.3 is bolt-ons, cam, and tuning

 

WOuld it be possible to install some 4.8L flat top pistons without having valve clearance issues? That would up the compression ratio abit...

 

You can bore the 5.3 and install 5.7 pistons, but only on a cast iron block. The cost would be greater then the reward. I got a 5.3 in a similar situation, the dealer I worked at had a truck come in with a shattered lifter, they replaced the whole motor. I would find someone to port and polish your heads, the problem with aftermarket heads is no one makes them for a 5.3, any aftermarket head you find will have the big valves in it. This won't work in a 5.3 the cylinder shrouds the valve and it will actually flow worse then stock. Take the spare set of heads you have and get them worked over buy a head shop that deals with LS1 product. I got mine done for $500, then when you heads are done do a cam swap and drop on your new heads. I got about 80hp gain with my heads and my 212/218 comp cam, with no loss of low end. and no suggnifacant change to driveability.

 

What he said ^^^^^. You can always add a set of heads but try this 1st. You'll be happy.

 

OK, I have an ext. cab 2wd. With cam, head work, throttle body, exhaust (will have to keep cats), programmer, what are some reasonable numbers to expect? How about adding s/c?

 

Why not get yourself a set of polished and ported 6.oL heads to lower the compression and then run the radix magnacharger and make between 10-12psi and then all you have to do is do headers and intake and tune and trany upgrade and you would be very happy with very stock like driveability or just get the 5-8psi setup on the stock motor with ethe bolt ons and you would still be really happy with the gains and not lose the driveability. Radix is the easiest and safest way to go in my opinion if you want more performance but don't want to lose driveability.

 

Oh, I never really said what I wanted to do with my truck. I would like impressive 1/4 mile times, but prefer better 1/8 mile since that is what I will be running the most. I would LOVE to see some 7's to low 8's. Is it do-able?

 

You should also look into HP Tuners or EFI Live to do your own tuning with..

 

their is alot u can do with a 5.3 u can bore a 5.3 to a 5.7 put a set of 317 heads with a s/c r turbo it will help.u can get alot of stuff off of e-bay and on here to cut cost down u can pick up a set of 5.7 pistons 100.00 and get block bore for around 150.00 pick up a cam and then the rest just follows cause once u start u just can't stop

 

With out boring the engine the 6.0 heads will hurt the truck because the cylinder will shroud the intake valve and hurt flow dramaticlly.