git_sum

iTrader: (10)

I've already purchased my cam which is a TSP228R at a .588intake and exhaust lift at a 112lsa. I also plan on running a 100hp shot of NX. Would a set of ported and polished 5.3's be better for my setup or would i be better off going with the ported and polished LS6 heads. Also what about putting bigger valves in 5.3 heads? What would be the best combo?

killer01ws6

I have that cam,
I went with PRC 5.3 Race Heads
2.055 1.60 Valves unmilled heads..

I think you can see my results are quite good.

Ragtop 99

iTrader: (7)

LS6 heads are better than 5.3 heads. However, the core difference adds almost $1k to the cost. 5.3 heads save money and provide extra compression without requiring as much milling as LS6 heads.

A 100 shot does not really require bigger valves. If you were spray 200 shot, I'd suggest a 1.60 exhaust valve

AKRA

5.3 heads are better if you don't plan on nitrous, turbo or supercharger. If you plan on any of these the LS1 or LS6 heads would benifit you more.

Good luck,

Al

goober35

iTrader: (1)

PM sent. I have a set of ls6 heads for sale.

I am making the same power as Killer01WS6 if you lock the converter. My budy 94forum2000Z made 5more rwhp than me on the same dyno only dif being the heads5.3. I think he had 40k less on his motor also and my heads are 66cc

CHRISPY

One thing I have noticed is that the 5.3 heads like a lot more timing than the Ls6.

Norm for LS6 seems to be around 24 degrees on pump gas with ~11.2-11.8:1 compression.

I had ~11:1 in my old combo and it liked 30 degrees timing with the 5.3L heads on pump gas as well.

I have heard other people finding the same thing. I have heard it has something to do with the chamber design but I haven't seen any hard analysis yet.

git_sum

iTrader: (10)

Well i plan on running a 100shot eventually, that's why i'm going to go ahead and run larger valves if i get a set of 5.3 heads. Or are nitrious and 5.3's out of the question?

killer01ws6

A 100 or 150 shot and 5.3s are not an problem

bigdsz

iTrader: (1)

Is there any problem running 5.3's with an 11/1 CR on a stroker 383 or 402? I seem to recall that the CR gets too high the bigger cu in you use. I've alresdy got a great set of AS 5.3's and would hate to have to get rid of them when I build a bigger ci in motor.

xfactor_pitbulls

iTrader: (16)

As far as LS6 cores being a $1k more. SDPC has bare LS6 heads for $582.00. It is what I plan on buying to do a build up from.

Brandon

94form2000z

iTrader: (10)

Goob we have pretty identical numbers on that dyno. I do have AS SII heads. They have stoick size valves and are not milled. I have 66k on my motor.

777

iTrader: (21)

i would imagine that is for just one core...cause gm sells them for like 1200 dollars a set the last time i checked....but if you can get both cores for $582...i will throw my plans out the door and get those...

Ragtop 99

iTrader: (7)

This is from SDPC's website:

12564825LS6 2002 Bare Cylinder Head $589.50 Add to Order

I beleive that is for ONE head. Are they showing them on sale elsewhere?

CHRISPY

582 is per head AFAIK

xfactor_pitbulls

iTrader: (16)

Yeah I was trying to say it is $5XX per head. I misread an above post. My fault.

Brandon