vff_jeff

iTrader: (10)

If so What kinda increase did you see, with stock cam?
Also what head gaskets did you use? I was just wondering what a compression increase alone would do.
I think 5.3 heads would put my ls1 at around 10.8cr. With stock thickness gaskets. and 11.1 with .040 gaskets.

vff_jeff

iTrader: (10)

Bump anyone?

camaroracer91

iTrader: (5)

better off posting this in internal section and people do run the 5.3 heads all the time only the ported one. I think tsp sell some

orangeapeel

iTrader: (18)

I will move it to internal.

Squirts11

iTrader: (14)

The valves in stock 5.3L heads are much smaller than the standard LS1 size valves. At the very least, you would have to accommodate for bigger valves.

LSxPwrDZ

iTrader: (4)

I made this mistake... don't do it! I have stock 5.3 heads on my LQ4 because I wanted a budget head to get my compression back up from the dished pistons in the LQ4. I had spare LS parts laying around so I came up with some stock LS1 valves and had the seats machined for the bigger LS1 valves. No port work was done on the heads, just had the valves put in. The car has some crazy bottom end and midrange with a G5X3 114lsa cam but you can tell that it's sucking through a straw. I'm confident with a set of ported 243's that it will pick my setup up at least another 40rwhp.

The car has run some good times at the track on the jug though. It ran 10.91@128 with this setup but on motor has only managed a 12.21@119.

disc0monkey

iTrader: (10)

all you need is to open up the intake valve seat and use ls1 intake valves. with this you will pick up over a stock ls1 head. * unless you use a huge cam like this guy^^^. anything less than .580 mid 22X duration i feel they will give you better et in a 3400lb car

Damian

iTrader: (89)

Putting stock 5.3L heads on isn't recommended. However you can make some damn good power opening up a 5.3L head with a CNC program and good valve job. I made 460rwhp with 5.3L heads 5 years ago through an 8.8 rear, and LS6 intake.

vff_jeff

iTrader: (10)

cool, thanx guys. What about using a .040 gasket to increase compression?

disc0monkey

iTrader: (10)

id be careful if your retaining your stock cam(which i wouldnt)

El_TransAm98

iTrader: (1)

I was trying to do this just get junk yard 5.3 heads changed intake valves for ls1 valve and have them only ported with mls gasket with ms3 cam I just never got and answer if this would work or have ptv clearence on my ls1

vff_jeff

iTrader: (10)

Why? What would happen?

disc0monkey

iTrader: (10)

CR may be too high

ramdaspadhye

iTrader: (3)

Moar overlap, ftw!

LSxPwrDZ

iTrader: (4)

I'll be swapping to cnc LS6 heads later in the summer! Do it right the first time and do t skimp on the heads. I already had mine and that's the ONLY reason they are on my 6.0!!!