junk or not??

[carfreak07]

I have the original 4.8 out of my silverado.....I believe the heads are an 862 casting......are these junk like I been told......on mortec, it says they are for 4.8 or 5.3....so are they the same as the 5.3 heads? I have several ls1's at the house, one of these days when I have the heads off one of them, will it be good to make the swap....I was told that the 4.8 heads were junk, just want some verification....I thought the 5.3 heads were exactly the same except they had smaller combustion chambers....that is what i need since I run N/A on everything.

[LS6_Silverado]

Yes the 4.8 heads are EXCATLY the same as the 5.3 heads. They both have 61.5 cc combustion chambers.

[thunder550]

Lots of LS1/LS2 guys will use the 5.3 heads to bump up compression. They aren't junk....used stock ones usually go for about $100 from what I've seen.

[RedHeartbeat]

Don't they have smaller valves?

[thunder550]

I'm not sure...all I know is that I have gotten a couple of requests from the GTO guys to try to find 5.3 heads, and put together one cross-forum deal for a guy from pt.net to sell his 5.3 heads to a guy from ls1gto.com.

[LS6_Silverado]

5.3 Heads
Intake Valve 1.89"
Exhaust Valve 1.55"

ls1/ls2
Intake Valve 2.00"
Exhaust Valve 1.55"

That info was taken from smokemup.com

[SoHo48]

yup thats it.. bring em down .020 you got you some 58cc's...