6.5 block with 6.2 heads

[southdave]

I have got a pile of 6.2 & 6.5 parts someone just dropped off a rebuilt short block magnaflux new cam and pistons.. ect he swearing off GM. thought may this the way to go for my turbo? and will my 6.2 heads work and how?

 

[ctmustang]

You have a few variables to deal with. Will the 6.2 heads even bolt up to 6.5 block. If youre going to boost it then you need to know are the 6.2 heads smaller combustion chambers. Is the valve travel enough not to interfere with Mr. Piston. Just a few thoughts after working on engines for 25 years I've seen a lot of money up in smoke.
Good Luck with the project
C.T>

 

[pigfoot63]

Heads will work but injectors are not the same nor is the angle they set at. The 6.2 injectors are taller, 6.5 are shorter. You can make the injector lines work on either one if you don't mind bending and prying. I had rather use correct lines for injectors.

 

[1stDeuce]

You need to surf another forum... I'd suggest GM-Diesel.com Information, and discussion, related to General Motors line of diesel engines, including the new Duramax, and other diesels in general. as a good start. I've seen this discussion there before. Most of the discussion will be geared toward running 6.2L heads on a newer, turbocharged 6.5L. I was looking into it because I thought I had a set of heads from a 6.2 that were good, but they ended up being cracked too, so my '96 got new heads. Probably from china.

To sum up what I recall, you'll have the following issues:
No oil supply for the turbo on a turbo 6.5L.
Need a spacer for the alt brackets sometimes, depending on the year of the 6.2L heads, alt configuration, etc...

Both those issues are likely not an issue on a truck that originally had 6.2L heads, and doesn't have a oil feed for a turbo. The combustion prechambers are actually better on the 6.2's for a non-turbo applications, for mileage at least, but probably not for mileage at 2600 rpm's... Some of the guys getting really good mileage with 6.5's were running 6.2 cups for prechambers, and there were certain years that were deemed better than others.

There were some injector differences too, and I think the really early heads were not desirable for that reason... Might have been '82 only. Again, in your case, your question is more along the lines of can a 6.5L block be run inside the guts of a military 6.2L, and the answer is a definite YES.

C

 

[ken]

!st deuce is right about the early 6.2 heads. They crack easy. You can tell by the threads on the injectors. They only made them in 82 so they are rare. You can bolt these heads on with on problems. And never know the difference. If you need a oil feed for a turbo use the 1/4 NPT port at the top of the block by the oil cooler lines. Thats where the Banks kit feeds from.