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which heads are better ? 6.2 or 6.5 ?

A

Acesneights1

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Well, as my 93 is coming under control, it's time to start planning my CUCV's upgrades. I have a complete 6.5 Turbo setup(GM4). It needs HG's anyway so now is a good time to do Arps and new gaskets as I doubt the Printoseal crap will hold up anyway. I got a DB2-4911 3129. I have one fairly new 6.5 head with diamond cups from the blown motor from the 93. The other head was destroyed when the crank broke. The head is an SS diesel head. Question is, should I blow 3-400$ and buy another matching head and change the 6.2 over to the 6.5 heads or just use the 6. heads ? Other than improved angle on the injs for the turbo..any real gains to be had either way ?
 
I had bad luck with Walts heads. They cracked around the bottom of the valve spring seats. But that was after 3 years so no warrenty left. Thanks again WALT!!!!!!
 
I don't think it will make or break your build up, unless you were going for all out performance. All in all, a set of old 6.2 heads with the stronger rocker stuff and some diamond precups wouldn't make for a bad setup :D
 
Well, thing is I have one good one but is it worth spending for a matching one or just use the 6.2 heads ? I don't recollect ever having a set of 6.2 heads crack on me and i have worked on plenty of them but they are also NA engines.
 
Ted's price might be too good to resist.:cool: Doesn't cost anything to check if they have any and how much$.:D
 
Acesneights1 said:
True.
Click to expand...

There's at least one good head on my spare 6.2 in the storage shed. It'll need a good cleaning but i found no cracks when i pulled that one. The other side, hell if i know. It could be ugly as hell, perfectly fine, or anywhere in between.
 
The 6.2 heads have larger exhaust valves. Swap the precups and check that they are flush or slightly above the deck. You want the better 6.5 precups as they make more of a difference than the exhaust valves do. 6.2 precups used with a turbo vs 6.5 heads is a 3 MPH difference at WOT around 65 MPH with a 24' trailer on a 6% grade. You get more smoke with the 6.2 precups at WOT as well. The injector angle is solved by header wrap and paint the manifold with the header wrap paint sealer. Throw on a couple of exhaust manifold gaskets for a little more room. You will have to pull the manifold to change injectors.

Cracks are found on both heads with the 6.2 heads known to crack and 'cured' by smaller exhaust valves. Cure did not work so you can use what you got that isn't cracked. If it wasn't for the screw bending valves both my rides would have 6.2 heads on them.
 
Your old 6.5 heads... They interchange without fuss I found.
 
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