What do I tell the driveshaft shop?

[MrSony]

Need a driveshaft for my 8.5 swap, so sometime this week I'll be going to my local 'shaft shop (giggity) and placing an order for one.

Short shaft th350, 8.5 as mentioned.

I know a GN driveshaft would drop right in, but those are nowhere to be found, plus they're at least 31 years old at this point.

So, if I understand correctly, I need a 51 1/2 inch (center to center of UJ) with a 3" diameter tube (preference), with a 27 spline Th350 yoke and 3R/1344 U Joints... is that correct?

Any input appreciated as always.

 

[64nailhead]

I measure. No guessing that way. No way for a suspension swap of parts to create an error.

 

[565bbchevy]

Measuring is the only way to make sure and eliminates any variances

 

[RegalBegal]

Need a driveshaft for my 8.5 swap, so sometime this week I'll be going to my local 'shaft shop (giggity) and placing an order for one.

Short shaft th350, 8.5 as mentioned.

I know a GN driveshaft would drop right in, but those are nowhere to be found, plus they're at least 31 years old at this point.

So, if I understand correctly, I need a 51 1/2 inch (center to center of UJ) with a 3" diameter tube (preference), with a 27 spline Th350 yoke and 3R/1344 U Joints... is that correct?

Any input appreciated as always.

Yep 51.5 is the correct lenght for a GN driveshaft. Another way of looking at it is, with no other changes the 8.5 requires a 1" shorter driveshaft than what you have in there now. You could check your math that way. As far as u-joints, 3R's are stock but others can be used. Mine uses a 1310 up front and a 1310/3rR conversion joint in the back. Thats just the way it came from Southwest Speed.

 

[fleming442]

If you're going to do it, do it right- 3.5" shaft with 1350 joints front and rear. Just my $.02

 

[pontiacgp]

If your driveshaft is in good shape why not have it shortened 1" and re-balanced. If you want to get a new tube it's not too expensive.

when you get the driveshaft back mark the orientaion of the slip yoke so if you ever remove it you'll put it back on the driveshaft the same way. It's balanced with the slip yoke installed and if you put the slip yoke on 180 reversed you can cause a vibration.

 

[TURNA]

Just shorten what you have. Save your money

You aren't making any power to justify anything else

 

[MrSony]

I cant shorten my driveshaft. Its my only car. I cant have it down for a week.

 

[TURNA]

A week???
the shop by me has them done in a couple of hours

I guess you dont have a shop near you

 

[pontiacgp]

I cant shorten my driveshaft. Its my only car. I cant have it down for a week.

If you are that dependant on your vehicle why are you changing something that isn't broken.