liss87

iTrader: (1)

I heard from someone that the 5.3 liter heads actually flow better than my 5.7 liter ones. I have a friend that has some and said he would trade me for my 5.7s. I have a lunatti voodoo cam in my car and have heard that those heads actually help the cam. is this true. the heads are supposed to flow better and up my compression. thanks

Studytime

iTrader: (15)

5.3L heads flow less CFM than 5.7L heads. The chambers are smaller in the 5.3L heads though.

Maybe there's a reason he wants to swap heads with you?

Ben T.

67Firebird455

iTrader: (27)

They flow substantially less than 5.7's. Port them, put some larger valves in, and you'll be golden. The increased compression should help with that cam and stock displacement.

N4cer

iTrader: (11)

Yup, the advantage to the 5.3 heads is the increased compression. Follow the above advice on porting and revalving, and you'll have a monster set of heads... probably pretty cheap.

1999 SS

iTrader: (3)

what would be a better head with the same head work(larger valves, bumped compression)out of the two?

Quik

iTrader: (7)

they claim 5.3s and 5.7s flow the same except the 5.7 has a larger intake valve but they do have smaller combustion to help aid in SCR

N4cer

iTrader: (11)

I think if you check, 5.3 valves are smaller, as are the intake and exhaust runners.

As far as which is better, that depends on your goals. For me, I'm not a top-end track junkie. I just play on the street. So I prefer my power lower in the rev range, and am willing to sacrifice some of the top end potential. But if you're wanting the top-end all out track times, I'd go with the LS6 heads. You can run a bigger cam with them unless you get way whacky with them.

orangeapeel

iTrader: (18)

5.3's are gonna be a higher velocity head. That is where you are getting more power from.

1999 SS

iTrader: (3)

so for the same amount of work done to each head the 5.3's will perfrome better. or is the 5.7 head a better track head(top end) and the 5.3 a better street head (because of velocity)?

BES Stroked Nova

iTrader: (24)

i did porting to my stock 5.3's and then ran out of cash for bigger valves. DONT DO THAT. Just do whatever it takes to put bigger valves in them, and you will have a good set of heads, for cheap.

stangkiller2005

iTrader: (15)

about how much hp, can be expected gain from these heads with bigger valves, and porting them?

silverlt1ss

i can't wait to see how my 5.3 heads run