View Full Version : 77 dodge truck driveline issues

10-13-2008, 12:39 PM
I have a 77 dodge truck that i have been restoring and i have some problems. I bought a 68 383 for the power plant in the truck and also big block 727 for the truck. The problem i have is what driveshaft coukd i use in this truck without having a custom shaft made. building on a budget! also what would be good rear end gear set or whole rear end to use to make the truck get up and go.

10-13-2008, 01:28 PM
I'm assuming 1/2 ton reg cab here.

the drive shaft from any 727 (SB or BB) truck of the same wheel base should be close.

As for the ratio, depends a lot on tire size, and what you plan to do with the truck. I had 3.55's in a 78 shorty and it was lots of fun. It was a factory BB truck, so it had a 9 1/4 but 8 1/4 will hold up too.(depending on mods of course)

10-13-2008, 03:37 PM
Truck is a short bed,extended cab.the original drive shaft was a 2 piece. i would like to use a 1 piece. Could i still use a regular 1 piece shaft out of a regular cab short bed truck.

10-13-2008, 04:23 PM
If you have an extended cab short bed, I don't see how the drive shaft from a regular cab short bed would be long enough.

Your first step should be simply measuring the length that you need. Measure from the u-joint center of the slip yoke to the u-joint center of the differential yoke. Now you know the length that you are looking for. With that in mind, you can start hitting the local salvage yards, with a tape measure in hand.

John Kunkel
10-13-2008, 04:34 PM
The factory installed two-piece driveshafts in installations that they thought were inappropriate (too long) for a one-piece.

10-13-2008, 05:33 PM
forgot to ask earlier but could i use rear end drom a newer dodge truck with 3.55 gears or possible a rear end out of say a roadrunner or big chrysler as long as the length is right. i figure i wil have to move the spring perches

peg leg
10-13-2008, 05:55 PM
Shaft was only $197.00 with new U joints and yoke on the tranny end.
You'll get a balanced correct lengnth if you go with a new one.

10-15-2008, 01:38 AM
The factory installed two-piece driveshafts in installations that they thought were inappropriate (too long) for a one-piece.

I agree.
If you had a two piece, it is not advisable to got to a 1 piece. Why would you? No reason to reinvent the wheel.

The longest one piece I've ever seen was on a 22 ft winni. The wheel base was actually only 3" or so diferent than a C body, so I guess they figured it would work.

As for a rear swap, I would think a gear swap in the diff you have would be way less work, and less money. Especially if you go with a used set. They pop up on ebay.

10-15-2008, 05:07 PM
For some odd reason they used a short tail auto tranny on an extended cab short box, and it used a hanger bearing, So if you now have a long tailshaft trans in there with a slip yoke, you could probably use a one piece in there. What length do you need?

John Kunkel
10-15-2008, 07:09 PM
I don't think the factory went to a short tail on the trans just so they could use a two-piece driveshaft.

They probably determined that a one-piece shaft with a long tail was too long (they tend to whip) and a two-piece shaft with a long tail would make one shaft too short so they used a short tail on the trans to make the length of the two-piece shaft more efficient.

10-15-2008, 11:55 PM
Ditto that, John. I have had a crew cab with long tail, two piece, club short tail, two piece, and regulars with long tail, single. Van with short tail single, and ling tail single. In the process, I learned teh crew and club both had the same shafts, but different tails mad ethe length difference. I think you are right on that John, they mixed and matched. ;-) PCRMike

10-17-2008, 07:45 PM
the problem is that the trans i have now is a 727 with a long tail shaft so i cant use a two piece shaft. a one piece about 75" would be perfect