I think the 6 cylider rear end had a couple ratios but that was it. When mine was still an I6, it had 3.20 and that was a good ratio with my 3 speed. On the highway it could have used overdrive though. That rear end took a dump and we had another one from an automatic car with 2.80 gears. That was in the car for a while. Man was that ever slow. It was nicer on the highway though.


I don't think you would need to upgrade the rear with just a few mods. If you do get an 8 inch though. Also if you run a split manifold or headers on the 6, don't run big exhaust pipe. Keep it around 2 inch maybe 2.25, but no bigger.

 

Bingo!!

IMO, a good ratio is the BEST thing that can be done for a small engine.

Make no mistake, those little 6 's can turn 4,000 RPM all day long....

All else being = , the 4.10 gears on the 66 turned a car that was built for "sconomy" into a FUN car to drive...

It is all about leverage...

 

My point with the T5 conversion is one of the things you get is better ratios, at the bottom for speed, and top for highway economy. That way, you can leave your 7" rear in the car. If you don't have a 3.20 diff, they are still find-able. The rarest was the 3.50:1, available in Equalock 64-66. I have seen one.

One of the 6-cylinder performance sites was talking about having the 3.50 gearset done, but I never heard anything more about it.

Don't get crazy with the exhaust. A 2" stock GT system is plenty.

 

I got Clifford Headers for mine and put on a dual exhaust. Looks good and sounds good. Call the boys at Clifford,they have a six rebuild book and they will talk your friggin ear off. These guys live and breath six's.

 

came across this in my research, don't know stock gearing for the 7.5 , but ford racing has three different gearing sets for the 7.5.

http://www.fordracingparts.com/parts...rtKeyField=255

 

I THINK that the 7.5 was an axle for the Ranger P/U, the 7.25 axle was used on Mustangs, Falcons, etc.