1978transam

I have been read some post on people putting on 5.3l heads on a ls1 motor. Why would you do this instead of putting on ls2 or ls6 heads?

cutlass_455

iTrader: (2)

Compression bump up?? I think also they have a bit of 'extra meat' in a few places they lend themselves to a full custom port job better.

Sales2@Texas-speed

iTrader: (5)

Like he said the 5.3L heads have the smaller chamber for that free bump in compression. They have very similar amounts of "meat" for porting, nothing real crazy there in the differences. The LS6's flow better out of the box, but once CNC ported they are very similar!

We offer both from PRC and can save you some money if you're looking to go the CNC head route. Let us know if we can help!

1978transam

Does this kill your gas mileage. I just don't want to go from 24-26 down to like 19-20?

Sales2@Texas-speed

iTrader: (5)

If you can keep your foot off the gas a bit, you should not notice any decrease in mileage. The improved cylinder head flow of a CNC or a properly hand-worked head will make your engine run more efficiently, which helps!

00pooterSS

iTrader: (40)

I would imagine you would actually see an increse, thats if you just change heads not if you throw a giant cam and a heavy foot in the mix, but just swapping heads will gain mileage because the heads will bump compression and efficiency, heads are win win.


Oh and the 5.3 truck heads have small chambers so you dont have to mill the **** out of them to get higher compression, that I can tell thats the only real benefit to them, and one other thing I have been wondering is if the 5.3's have quench pads, if not then the LS6's would get my vote.

1978transam

I have a 2001 silverado, which has the 5.3l in it, that I don't use anymore. Could I just take the heads off of this one and put it on my 00 trans am or do I have to take them in to get fixed so that they will run right?

Sales2@Texas-speed

iTrader: (5)

With the heads being completely stock and unported you will not see appreciable gains.

00pooterSS

iTrader: (40)

Alot of what is done to the aftermarket 5.3's is port and chamber work that increase flow and efficiency, as Matt said it wont be an "appreciable" gain but you would have a gain in compression from going from 66.67 cc chambers to 61.5 ( believe those numbers are correct, correct me if I am wrong ) I would venture to say slapping them on the compression gain would be around 15-20 but worked over your looking at closer to 40+ depending on supporting mods. Also I do not know what the heads flow stock for stock, there could even be a drop in power if the 5.3's ports are lesser than the stock as far as flow.


Matt could you chime in on if the 5.3's have quench pads like the LS6's do please.