I had a 78 GMC 6500 with a 4-53T detroit diesel in it. Was the 4-53 offered in your 64?

Vaccum pump is no problem, I have a belt driven one if you would like it.

Or you could switch to a hydrobooster.

You may find an onan/cummins if you ask around here, I bet you will find someone with a few...

If you only want to improve on gas milage than you may want to think again on the conversion. Not that a diesel can't get better gas milage, but you are probably going to spend lots more money and time doing the conversion than the cost of the extra fuel you will burn for the rest of the time you have the truck if you leave it gas.

That's not to say don't switch, but you may want to have a few more reasons to do it so you won't be dissapointed in the money you actually loose when it is all over.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-