SLO TRUCK

iTrader: (3)

Here is my set up. 5.3, 212 216 .525 115 cam, front mount 70mm with IC. I am looking for the best heads for my set up. I will be running about 12psi. Just looking for a stock replacement. Which would be best. 243's, 241's, 799's. Not looking to lower the comp way down so 317's wont work, i dont think. Just looking for opinions. I post this on some other boards so just seeing what yall think.
Thanks

trever1t

iTrader: (14)

243/799 heads

I thought you were SC for some reason on the other forum, oops. the 243/799 heads will lower CR a bit, better for turbo applications.

FarmTruc

iTrader: (5)

Honestly, I don't think it's going to matter which heads you run. The small difference between those heads isn't enough to notice.

With my 408, truck intake, stock throttle body, STOCK HEADS, cam only, laid down 821hp on only 12psi. I don't think heads make a huge power difference, but the thick deck of aftermarket heads would help clamping force, but you're only going to push 12psi through'em.

SLO TRUCK

iTrader: (3)

good to know

trever1t

iTrader: (14)

What are the "stock heads" on that 408? Surely 243/799 heads will flow better than what comes on a LM7

FarmTruc

iTrader: (5)

They are 100% stock, never touched, brand new 317 heads. No valve job, no valve swap, no port, polish ect.
Now I'm taking one step back and saying we did put springs on the heads due to the cam.
More details: Eagle 408, 10.6:1 compression, twin turbo, cam, stock 317 heads, stock truck intake, stock truck throttle body, Good fuel system, 12psi, laid down 821hp.
This is the only pic I have from the build, it's my '94 and was actually a customers 408 engine, mine is a low compression 408 with diff cam but still stock heads.

here's the post of the dyno progress, btw no intercooler either.

trever1t

iTrader: (14)

Stock 317 (243/799) heads breath significantly better than LM7 heads, no?

I have stock heads as well (799's)

Hawk179

iTrader: (1)

Heads make all the difference in the world, but the way you guys are talking around here you are only talking about dyno numbers. So in that case....not really.

FarmTruc

iTrader: (5)

Yes, without a doubt. But I was just saying that I bet he doesn't notice much difference by going either way, since his truck is forced fed.
I got this post off topic, sorry mark, hahaha!

FarmTruc

iTrader: (5)

yes they do make a difference, but going back to his question, not really.
he's running a 5.3L, pretty much stock, with a turbo.
Regardless of what head he chooses from the list above, his engine isn't going to make that much more power.

With 10psi, it'll probably put out 450hp or so, add a few more psi, and it'll still be under 490hp, at that point, how much do you think 243 heads are going to give this engine over the LM7 heads?

Keep in mind, we're only talking his setup, and the three head castings above.

We're talking stock heads on a turbocharged 5.3L.