I was told by who I bought them from they are more like 62ish. Im not 100% sure though.

 

this is correct. 10.6 is what i was told.. love them on my lq4. if you search you'll find my dyno thread.

 

Ok guys... you all have me confused on some things.. forgive me, I'm still pretty green.

the TSP site has these listed as 220cm heads, that would be 55cm per combustion chamber right?

the stock 5.3 heads are ~61 cm combustion chambers iirc, so in order to boost compression they would need to be smaller than 61 cm combustion chambers, right?

I may be way off the reservation with this, I'm just trying to learn both about heads in general, and this item specifically.

Thanks in advance, I thought I had it figured out, now I'm not so sure.

 

First off it's 220cc not 220cm. And that number is intake runner volume. Has nothing to do with combustion chamber volume.

These PRC heads are based off of production 862/706 castings according to the website which should start out as 61cc chambers. The website doesn't list the finished volume.

Also, another thing you need to be aware of, these heads will not produce the same compression ratio on all 5.3's

NBS or GenIII 5.3's have 706/862 heads with 61cc chambers and have dished pistons.

NNBS or GenIV 5.3's have 243/799 heads with 64cc chamber and have flat top pistons like a 4.8.

Hope that helps, and sorry didn't mean to threadjack, free bump!

And I really, really wish I had the cash for these right now.

 

no problem ^^ good info, thanks

 

Bump!!

 

on a NBS they are 61.5cc

 

How much would shipping be to 67871 Scott City, Ks and PP fees?

 

I'm near the beginning of my mods. How would these heads react to a stock tune? I've only got shorties and exhaust done. What's shipping to 97377?

I've got a 2000 Silverado 5.3L. Are these appellate for a daily driver?

 

Do you know what valve springs are installed in these heads?