I am curious what is the difference between the 6.5 and 6.2 blocks.

The bore. The 6.2 is just under 4.0" at 3.9758"-3.9789". The 6.5L std is 4.06" stroke is almost identical at 3.818 for the 6.2L and 3.82 for the 6.5L. The 6.5L has the better flowing head with a slightly larger intake valve and waterpasseges. The timing cover on the '94 up 6.5L has the CPS port.


Compression was 21.3:1 in the 6.2L and 21.3:1 in the 6.5L. but the 6.2L pistons come in 19:1 and 6.5L pistons come in 18:1.


The '82 block is sapposed to have higher nickel content and the 599 cast as well as the AM general blocks.


I'd happily run an '82 6.2 19:1 with main girdle and 6.5L heads.Edited by: quantum mechanic

QM, I might give that a try, I have spares. Thanks,

QM, so is there any way I can use 6.5 pistons in a 6.2 block? Like bore it .010?

I don't have any personal experience doing that, but it would seem possible to bore it. I'm not sure there would be any advantage, less cylinderwall to bore again. I wonder if it's possible to repiston a 6.2L to 19:1 and then after it's worn, bore it to 4.06 for 18:1 6.5L pistons later? Edited by: quantum mechanic

I dont' think there is enough to bore them the .080" in bore it takes to equal the 6.5 ..........I think you'll strike water.

Grape,


Are you working a 19:1 6.2? I've seen the pictures and I'd like to hear anythought's about what block is prefered over all or any building stratagies you've taken to.Edited by: quantum mechanic

599 is the first choice late '91 till late '93, then the first '94s with the 2929 non oil spray are next. This is for 6.5 stuff. With 6.2's it's supposed to be my old '82 660 part number because of some nickel content BS, which I can't prove. However my '82 had no cracks in the main webs when i pulled it apart early this spring. I'm working with a 6.5 but the compression I'm fixing myslef, it only takes moving the top of the piston down .010" to equal 1 point of compression based on my math. I cut a stock piston in half on my bandsaw just to see how thick it was for machining purposes and the thinnest point was .490" thick right in the center. If i shorten the rod .010" and take .010" off of the piston I dont' think I'll hurt anything but that gets it into the high 18's-1.

Can you explain how you'd shorten the rod. I'm really interested in this.

machine the rod cap and re-hone the rod to size.

A low dollar approach. Is .010" the limit you can shorten it before it gets weak? Just wondring ow you arrived at it?

What should the 6.2 read on a compression gauge? I have tested my 94 6.5 and got 375. I also tested a leaky spare 6.5 and got 200, but I am working on the heads for that. I have a number of 6.2's and they are very cheap, so I may put together a few 6.2's for fun.

same as a 6.5, cam is the same and mechanical compression is the same.


As far as the rod goes, you can probably shorten it more. You can offset the small end bushing as well. I've heard as much as .040" being changed on carrilo and lentz rods for our race stuff.