The HO35 means nothing to me other than it would make a good password. A rear gear RATIO would mean a lot. I think my 37 Buick might be a good comparison as it has a 263ci engine, overdrive automatic, 4.11 gear, and 29" tall tires. The final drive in OD is 2.88---the same final drive most all overdrive vehicles had for years. I removed the sun visor, outside mirrors, and used 215 (narrow) radial tires inflated to 40psi. This bumped me to 16.5 mpg on a 3000 mile trip compared to the 12 mpg with the stock factory set up. A lot of work for not very satisfying results when one considers we put an LS3 engine in a customers 52 Suburban that clicks off 22-23 mpg and can melt the tires.
