6.2 Redblock Theory

[2INSANE]

I had one apart back in the mid 80's that some clown had added a turbo to and melted a few pistons trying to make a bazilllllion HP

Aside from the melted pistons it was solid.

There were zero cracks in the bottom end......

The alloy story is one that has circulated around a lot over the years......I can't confirm it though.

The red blocks were 1982/83 only IIRC.

The early heads had coarse threaded injectors I believe....which is not a big deal, just something to remember when building.

The rocker arms were a cast type rather than the stampings that you will see in the 6.5

I had one of those engine blocks and finally let it go a while back.

Good luck.....Fun stuff

Ooo yes yes! Please tell me more!

The red blocks and coarse thread injectors were unique to the 1982 M/Y. Original heads had larger valves, as well. A crack-free red block and original heads are more and more rare these days. Certainly a diamond-in-the-rough, if you can find one. However, I wouldn't look for one if huge power is the goal. These, and subsequent years, lived a long, happy life due to the modest power demands of the time, and it had, essentially, no significant competition. A banks or ATS turbo system didn't destroy them if installed in accordance with recommendations. If you're looking for greater power, keep in mind, the block was never the primary weak link.

I just want to build one and do every mod possible to it. Fully modernized and push it to its limits! No idea what I would put it in.

This Red Block Theory has been a theory long enough! IMO. I am tired of reading about it! I want to be the guy that has hard data about the Red Block and if it does have a higher nickel cast, I want to be the guy to to build it and throw everything at it! I have a formula in my head that I think would turn it into a Duramax Slayer! Call me crazy?

But finding one with a good block now a days… Seems impossible.


To get this party started, I will take 2 clean and uncontaminated samples from my 6.5 Optimizer Heads and Block and send them into a lab for testing. First I need to find a lab…

Anyone have ideas which lab to contact?