I found a Dana 60 for our M68 . What do you guys think of a 3.54 ratio to go with the T5 that I have in it . The truck is now finished ,passed the OOP inspection and is insured and registered . The old rear end is toast , probably why it got parked. I'll post some pictures when I get the chance .

 

Won't win many drag races or pull stumps, but should make a really good driver/cruiser.

 

What size tires are you running? And which T5 is it? If it's the 3.35 first gear T5 and you don't have too tall a tire you should be OK. Might not be so good for pulling a load. Plug your numbers into this calculator Gear Ratio Calculator for more details on speeds / rpms in each gear.

 

Not sure abot ratio's of trans. gears . it came out of an S10 that had a 4.3 V6 . No tag.

 

What engine do you have? A flathead may not pull 5th, this page (The T5 page ) shows all V6 T5's having a .73 5th and 3.50 1st. 5th would effectively be a 2.58 axle, mighty tall.

 

It's got a flathead . What would be a better choice 3.73 or 4.10 ?

 

I think 4.10 would be the minimum, since an M68 is a couple hundred pounds heavier than an F-1. Is it mostly flat up there? 4.10 would give right at 3.00 in 5th, about 2300 RPM at 65 mph with 28" tires. I'd verify your 5th gear ratio before committing!

 

Saddly Dana 60's of the required vintage are extremly rare around these parts . This one is from a reputable wrecker in complete condition for 249.00 so if it turns out to be a real dog I can allways change out the ring and pinion .

 

I think it would be worth the wait, or worth a drive down to MT or WA for the right one. Not much driving time left.

 

F250 Dana 60: 3.54-1 introduced in 1966, 3.73-1 in 1967. 3.54 is very hard to find.

 

You can always just run in fourth gear with the 3.54 axle. I too think that 3.54 and overdrive are too tall for a stock flathead in a 3/4 ton truck.

 

I was also going to say so you might not use 5th very often, who cares. Depending on tire OD you may be able to use 5th on the flats with no load. That is what makes manuals so nice, don't like the gear you're in just reach down and change it.

 

The T5 was installed mainly to make shifting easy for my son Ian and my wife Patricia

 

Also I found the T5 ID Tag it's 13-52-193 out of a L4 S truck not a 4.3 V6. 1st is 4.03 and 5th is .86 . That may help a little at least in the bottom end .

 

That makes a big difference. With a 3.54, that is about right for 65 mph @ 2350 RPM (depends again on tires), but 1st is pretty worthless except for stump pulling.