IDLife

Forgive me if this has been covered before as I am certainly NEW to the LS-Scene with a 2013 Caprice PPV 9C1 L77.

In my removal of the L77 engine in my new-to-me car... I am learning the differences and similarities as I go.

This is thread for more info on the Caprice Build

I have noticed several LS3 casting 821 heads for sale, some ported or not... and aside from the lighter valves, is there any benefit to the 821 castings versus the 823 heads?

I am already removing the DOD and using a 2007 Corvette LS2 block for my rebuild... just trying to learn more about which legos to use in building another LS for my eventual twin-turbo build.

THANKS!!

Tuskyz28

That's really the only difference between the two heads is the weight of the valves....

lil john

True Tuskyz, also the 821's have less meat, *Some porters don't like to go over 270'cc while the the 823's are good to around 280'cc.

flintwrench69

iTrader: (11)

So which castings come with the lightweight valves?

Tuskyz28

821s.... LS3

flintwrench69

iTrader: (11)

That's what I got, 821s. Mine aren't stock heads theyre GMPP heads.

locosmith

The 821 from the ls3 have 3 angle valve seats while the 823 have 2 angles only.

Again the 821 have lightweight valves.

KCS

iTrader: (20)

Where did you get that info?

JimmyGTO

Phil @ Advanced Inductions gave me a quote on the 280cc version on my #821 heads.

Frankenstein

We have seen no issues with thickness in the 823 vs the 821. Our port comes in at 282cc and the same cnc program is ran in both heads. The only heads that we have seen thickness issues with is the 5364.

gunter96ws6

iTrader: (12)

What sort of issues are you having with the 5364's?

Frankenstein

Only in a ported situation, with our port design we found that the 5364 does not have enough material in the floor of the exhaust port.

KCS

iTrader: (20)

Good info, thanks.

LT1PWRD

iTrader: (2)

which rect heads have the thickest decks? What do they check out at, similar to most cathedrals?
thanks

carmine lucchese

WRONG a lot of you guys need to Learn a little bit more about what you think you know just saying one has a Different angle cut race ready with Hollow stem titanium valves 3 angle back cut It weighs 90 g Also the exhaust valve weighs the same so they're balanced out and the other 1 just has a 2 angle cut A lot heavier but is designed for more torque application that's why it's in the truck And yes the 823 is a lot better after you add all the upgrades it flows a lot more there is more to port Special note do not get rid of the swirl ramp you'll only game 3 more horse power if that and lose a lot of torque plus create more drag I been porting for over 30 years and tons on the ls heads Also do not watch some dumb-*** on YouTube That can't give you any numbers or why you port heads a certain way from drag Port design port angles or anything you'll just mess your head up Remember if I can do it you can do it good luck guys

85Iroc

iTrader: (12)

Can I buy some punctuation?

G Atsma

Probably not at this point..... lol
It pained me to read that too.

RB04Av

Punctuation and capitalization are the difference between "I helped my uncle, Jack, off his horse", and ... something else.

G Atsma

ROFLMAO!!! Oh yeah.....

mikebell72

how much for this port job ?