SM318 to Saginaw 4 speed

[Sleipnir]

Originally Posted by crazy longhorn

If you can find a complete shaft, from a 71-72 truck, with an inline (same wheelbase as yours), it will have the longer saginaw trans. The saginaw is the same lenght (3 or 4 spd)& the shaft should bolt right in Best of fun, Longhorn

Another question for you longhorn. Would switching to a single driveshaft be better? The carrier bearing has never been replaced so I'm wondering if switching to a single driveshaft would be better. My only issue is I need a 69 inch shaft from what I can tell. At least that the measurements from the tail shaft on the transmission to the end of the diff.

[crazy longhorn]

You will be right on the borderline of a no no, with a 1 pc shaft that long. Some guys have done it, but you need a large diameter tube to support the lenght. On a 4-4 1/2" diameter tube, a steel shaft will be very heavy, & may be hard to balance. Some vans use a large diameter aluminum shaft....but you may also have issues clearing the hole in the crossmember for the carrier bearing. IMHO, you would do better to shorten & rebalance your shaft....but you may talk with some driveline guys on the pros/cons. I beleive there are some guys on the board that do driveline work for a living....I would leave that to them, for their expertice Longhorn

[Sleipnir]

Originally Posted by crazy longhorn

You will be right on the borderline of a no no, with a 1 pc shaft that long. Some guys have done it, but you need a large diameter tube to support the lenght. On a 4-4 1/2" diameter tube, a steel shaft will be very heavy, & may be hard to balance. Some vans use a large diameter aluminum shaft....but you may also have issues clearing the hole in the crossmember for the carrier bearing. IMHO, you would do better to shorten & rebalance your shaft....but you may talk with some driveline guys on the pros/cons. I beleive there are some guys on the board that do driveline work for a living....I would leave that to them, for their expertice Longhorn

Thank you sir! I didn't want to shorten mine because they look pretty beat up and I called a drive line shop and they quoted me $600

[Captainfab]

IMO if you use the HD carrier bearing, there is absolutely no reason to not use a 2pc driveshaft on a longbed.

[Sleipnir]

Originally Posted by Captainfab

IMO if you use the HD carrier bearing, there is absolutely no reason to not use a 2pc driveshaft on a longbed.

Do you think that because the driveshaft is 50 years old I should replace it? Looks pretty rusty but I don't think I have any vibrations. Also, I may need one of your brake booster brackets soon

[Captainfab]

Unless the rust is so severe that it has compromised the integrity of the tube, there is no need to replace it. Just clean it up, paint it, replace the u-joints and carrier bearing and you should be good to go. And of course shorten the front shaft if needed.

I will be leaving on vacation tomorrow and will be back in the 14th. I can build and ship a booster bracket to you then.

Originally Posted by Sleipnir

Do you think that because the driveshaft is 50 years old I should replace it? Looks pretty rusty but I don't think I have any vibrations. Also, I may need one of your brake booster brackets soon

[Sleipnir]

Originally Posted by Captainfab

Unless the rust is so severe that it has compromised the integrity of the tube, there is no need to replace it. Just clean it up, paint it, replace the u-joints and carrier bearing and you should be good to go.

I will be leaving on vacation tomorrow and will be back in the 14th. I can build and ship a booster bracket to you then.

Thanks for the advice! Much appreciated and I'll let you know after the 14th if I need one