is that a direct swap or are there mods to be done to add 5.3 heads on their LS1? I know it boosts compression and adds some power, but how much is gained from 5.3 heads? They are the same valves and 62cc instead of 67cc chambers right? I am asking because I have a couple sets of 5.3 heads and was wondering about the LS1 mod.

 

they are a direct fit, but just to swap stock 5.3L heads for stock 5.7L heads is not worth the effort. the 5.3L heads have a much smaller intake valve(5.3L= 1.89/5.7L=2.00) so produce less intake airflow. they do increase compression and might add a few ponies but again a stock for stock swap is not worth it IMO.
If you have some heads you want ported give us a call we can turn those 5.3L's into some killer heads for less than you might think.

 

How much would it cost to work over a set of 5.3's ?
I am very interested. I know stock 5.3's arent much good becasue the valves are smaller but I may be able to get a good deal on a set here and I was wondering what is would run.

 

wouldnt the 1.89 and more compression make more low end torque on a LS1?

 

IMO you will not see enough gain to make it worth the cost and effort to do a stock for stock swap. I know what I give for 5.3L heads but for this excersize lets say you get the heads for free even, to do the swap you need the following
new head bolts -$50.00ish
new gaskets - $50.00ish
5qts oil -$10.00 (use cheap stuff the first time and change again after 300mi)
oil filter -$10.00
coolant -$8.00
freon -$15.00
total -$143.00
labor intensive to remove all of the needed parts to take out 1/2 the motor, figure a good day first time. have on hand(or be prepared to buy) an oil sending unit as those things are easy to break when removing or installing the intake manifold.
you may gain 10-20hp/tq due to the higher compression, but to me it reall is not worth the effort

 

my 5.3 heads are next to nothing for cost.. what does it cost to do 2.00 or better intake valves? what are max. size valve fit? Sorry for so many Qs.
Gasket/Port + porting/matching I can do myself. Thanks!

 

on a stock motor a 2.02/1.57 valve is all that is needed. a good set of valves will run about $200(any of the major brands like REV, Manley or Ferrea), machine work to allow the valves to fit, $150.00 to install new intake seats, $250.00 to do the valve job/blend the bowls, install bronze guides $150.00

 

Not to get too off track but...do the 5.3 heads have smaller chambers than LS6 heads?

 

yes they do
LS1 5.7 heads have a 67.67cc chamber
LS6 5.7L heads have a 64.43cc chamber
LS1 5.3L heads have a 61.63cc chamber
at least off the top of my head those are the combustion chamber sizes

a direct replacement of heads with an LS6 head will yield a compression ratio of about 10.5:1
The 5.3L heads will give about 11:1 compression

 

LS1, 5.3, LS6, & 6.0 tech info:
cams, heads, flow, valves, etc..
http://smokemup.com/tech/ls1.php

 

5.3 heads 61.15cc...




www.mortec.com

 

I have the 5.3 heads on my SS. It's got the 2.02 and 1.57 valves. I've also got the flow numbers laying around somewhere if you want them. That's what's the most important.

 

cool! If you got those flow #s email em to me please or PM me here. Thanks!

 

ninetythreez, did u get those flow #'s?

 

unless you are doing all the work yourself or you have a friend it will cost an arm and a leg. But, on the parts, considering i just did it....your going to pay a little more. Racing valves aren't cheap from ferrea(the best, if you can't afford ti =)). Head gaskets($100), spark plugs, intake gaskets($75), header gaskets, oil, oil filter, coolant(dex cool expensive ****), not to mention the outrageous prices on head work. Even if your doing it yourself it will cost over 1K in just random *** parts including heads and valves. Thats if you don't even opt for roller rockers and hardened pushrods, which are 700 for a good set. Good luck man.