Hey guys, im new to performance truck. I'm in the process of building a 5.3 for my v6 firebird. I'm on VERY tight budget, so I went with an 02 ls6 cam and ls6 intake. My question is, what should a do for the heads? I'm getting new valve seals and ls6 springs. Heard the stock heads suck, 243 ls6 heads flow better but lower compression. Would 4.8 flat top pistons help? I've got resources for Texas speeds 5.3 heads but they are still more than what I payed for the complete engine and cam. Let me know what y'all would recommend!

 

The nnbs 5.3 heads are 243s. Maybe you can find a set of these for cheaper? Seems to be a popular choice. You can always mill them for better compression.

 

Are the corvette valves different than the trucks? How much is it to get them milled?

 

You could get 4.8 pistons with 243 or 799 heads. This would basically give you an L33 5.3 with an ls6 cam in your case. Compression would be 9.9 to 1 where as stock 5.3 compression is 9.5 to 1. Or as stated above you could just get the heads milled and stick with the stock 5.3 pistons. Just depends on whichever is cheaper in your case.

 

I say get 799/243 heads, mill them .020-.030, and slap some 4.8 pistons in it. It'll run great!! 799/243 heads are the same thing, just cast at a different factory. The only difference between the LS6 243 heads and the nnbs 799/243's are the valves. Same size, just the LS6 valves are hollow/sodium filled stem valves, just a little lighter.

 

What is your budget? We can give you better ideas if we know what your limits are.

 

I've got 4.8 pistons if your interested..

 

How much of a gain would the heads and flat tops be over stock? Worth the 500 bucks or more?
Edit: my budget would be about 600 for complete heads and pistons...

 

For $600 I'd go for new pistons and floating pin rods, both can be had for your $600 budget.

 

For $600 I'd go for new pistons and floating pin rods, both can be had brand new for your $600 budget.