I have a SY-C6-1350Q yoke to go into my TKO 600 and am trying to match that to a stock driveshaft in my 83 camaro.

I purchased a 5-1350X which fits perfectly in the yoke but it doesn't come close to fitting in the stock driveshaft.

On the driveshaft:
From injection hole to injection hole I measured 3.125"
cup size I measured 1.125"

What do I do from here? New driveshaft? I understand that there are some variation between driveshafts... 4th gen driveshaft perhaps?

thanks

 

You need a bastard joint (conversion U joint)
That yoke uses a 1350 U joint (biggest one), your driveshaft will be a 3RN/S44 U joint.

So you need a joint that has a 1350 on one side and a 3RN on the other.

That would be a Neapco #2-1153. You can use that Neapco U joint or cross that number to find the same joint in the brand of your liking.