Humvee block is goin in! Is it possible to machine adapters to allow a GM 6.5TD intake manifold to bolt up to 6.5 Hummer heads. Better yet, are there adapters out there available to buy? Would like to avoid swapping to truck 6.5 heads as the humvee heads are very low miles. Also, I have heard I will need metric bolts to bolt the 4L80E tranny to the hummer block. Anything else I should know before starting?

Looks like nobody knows or cares to comment. Let us know how it goes, you'll have to fabricate anything you do. Nobody makes those parts.

I have heard the heads are cut at different angle, and I am not sure how you will compensate.

Unless they have changed something recently (and I doubt it) there are no differences between hummer heads and civilian heads. Think about it for just a moment, this is a GM design, GM knows that to make money, parts need to interchange. Hummers do use different headers, turbo's, oil pans(more capacity) fan clutches and a few other things that I am sure I have missed, but the basic long block is the same as the engine in your truck!:eek:

True to a point, DCam - van and hummer TD intake surface angles are flatter, more horizontal to allow for the center-mount turbo and manifold.
'The intake bolts are nearly vertical.

And, all 6.5's use metric fastener hardware

The intakes are different as you say gmctd. ( manifolds bolt up at different angles ) Going to talk to a machine shop early next week to see if they can remove some meat from the matting surface on my GM manifold. Want to take enough off so an adapter can be machined using a gasket as a template, that will fit between the manifold and head. Just have to be careful as to not remove too much from the intake manifold. Don't want to be breaking the cast when torquing bolts!

What about using the van intake manifold, and create tubing to run from the stock turbo position to the crossover between the manifolds? If you can not get the regular 6.5 intake to work, this may be your next option.

I guess I haven't seen a late model hummer engine up close and personal, late model civilian blocks had the boss for the oil return on the top of the valley for the center mounted turbo. NA hummers used exact same heads as civilian trucks, those I have had my hands on.:eek:

Need any pics? I have a couple of HMMWV's out here. I think I can make a copy of an ETM (electric technical manual). I think it says unclassified on it. Just let me know. -Chase

how about some custom fabrication and a custom intake plenum???.. aluminum might be hard to make it out of, but mild steel would work ok too, and it is easy to work with.. you could be the first with a manufactured sheetmetal intake manifold... ;)