Can you use heads of a 6.2 to a 6.5L?

[Klink K5]

I have a 1996 k3500 6.5 engine that has cracked heads on it and I was wondering if I could use the heads off a 1984 ish 6.2 and have the same power. I have not reasearched this at all yet so I am looking for somevaluiable input. Thanks, Klink

 

[imiceman44]

I have a 1996 k3500 6.5 engine that has cracked heads on it and I was wondering if I could use the heads off a 1984 ish 6.2 and have the same power. I have not reasearched this at all yet so I am looking for somevaluiable input. Thanks, Klink

Iknow you can't get the same power since the heads are different.
I know people do the opposite and bolt a 6.5 head on a 6.2 for more power, basically bigger valves and better flow design.
Maybe someone who has tried this might chime in.

 

[79Beast]

I read a tech article on a site (Oliver performance maybe?) where they used 6.2 heads and basically made them into 6.5 heads through portwork, valvework and such. I think you can use them, but it would be a waste of time and money. Better to fix it right in my opinion. You'd feel sick to spend the money, get it all put together and be disappointed with the reduced power output.

 

[AgDieseler]

The heads do bolt up. One can put any prechamber desired into any 6.2 or 6.5 head. Aside from early 6.2L heads, all the valve sizes are the same. The cooling passages were upgraded for better flow with the 6.5L heads. Around '90 or so (I can't remember specifically) the injector angles went to a more vertical configuration. This is likely for extra clearance for an upcoming factory turbo package, but there haven't been any specific performance advantages attributed to this angle change.

While the heads may make some slight difference, the best value for one's money during a full 6.2L rebuild, assuming one already has crack-free heads, is to rebuild the 6.2'ers on hand with turbo prechambers and short-body turbo injectors. That's where the real power comes from.

Cracks between the valves seats are repairable. Your local machine shop should be familiar with the SAE repair procedure, and if not, I know there are several mail order places that will do an exchange with you. The Diesel Depot comes to mind.