Here is a 64 Chevy with 4-53 on Ebay, the link is also in the ebay links section (where I found it)
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=017&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=270263016334&rd=1

I doubt a 4-53 with no turbo is much of an improvement over your gas engine, although it may get better fuel mileage, and it will certainly make more noise.

Grigg

Grigg

•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
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-