7.3idi swap

[kbenz]

Thinking bout putting my 7.3idi/zf5 in my 65 Chevy c60. How do you think it’ll do with the 2 speed rearend?

 

[Prideofthewest]

2 speed would be cool, you know what the gear ratios are? Old trucks with 2 speed rears usually were pretty low geard even on the high side,

 

[Jesus Freak]

I think you'll be incredibly happy.....

 

[kbenz]

2 speed would be cool, you know what the gear ratios are? Old trucks with 2 speed rears usually were pretty low geard even on the high side,

Yeah. I’m more concerned about the rpms
possible gear ratios
6.40/8.72:1 or 5.83/7.95:1

 

[KansasIDI]

With 5.83s, 9.00-20 tires, and in direct drive gear, at 3300 RPM you would be doing almost 70 MPH

With the same tires, also in direct gear, at 3300 RPM

7.95 - 50 MPH
6.40 - 63 MPH
8.72 - 46 MPH

 

[kbenz]

2 speed would be cool, you know what the gear ratios are? Old trucks with 2 speed rears usually were pretty low geard even on the high side,

With 5.83s, 9.00-20 tires, and in direct drive gear, at 3300 RPM you would be doing almost 70 MPH

With the same tires, also in direct gear, at 3300 RPM

7.95 - 50 MPH
6.40 - 63 MPH
8.72 - 46 MPH

Thanks for the info. Here’s the plate on inside of cab

 

[nelstomlinson]

I had a couple of Sixties C60s, the second had the two speed rear end. Don't try to shift it when it's cold!

 

[Grumpy bruce]

You will be happy . I put a 6.9 in a 77 GMC. That was in 1986. I didn't stick with a Ford transmission so I had clutch problems. other than that it ran great. 355 gears GMC four speed

 

[u2slow]

Theres a great variety of rear disc diffs from newer diesel trucks 90's/00's freightliner, International, Hino, Topkick, etc with 4.xx-5.xx ratios

 

[kbenz]

Theres a great variety of rear disc diffs from newer diesel trucks 90's/00's freightliner, International, Hino, Topkick, etc with 4.xx-5.xx ratios

this has the big 6 lug 2 speed in it. It's not original it's a 18,500# axle. Front is heavier than it should be too. It actually uses all 10 studs. typically they only use 5

 

[kbenz]

You will be happy . I put a 6.9 in a 77 GMC. That was in 1986. I didn't stick with a Ford transmission so I had clutch problems. other than that it ran great. 355 gears GMC four speed

I'll be sticking with the zf5 for sure. I need to get reverse fixed though. Not sure what I'll be doing for an e brake Though