rear brake spiders?

[tom1361]

hello all, looking to convert my 1962 b 67 rear brakes over to something more modern. will the rear spiders from a tandem axle rd mack work on my b 67 or will i need to find them off of another single axle mack?? the bolt spacing is 3.25 inches on both trucks center to center for the mounting bolts. i'm not to sure if the later spiders will give a different "offset" to the positioning of the brake shoes. any opinions are appreciated. thank you. 

[ranchhopper]

I have a set of spiders off a 73 R model sitting in the shed.

[tom1361]

thank you. i'm going to stay with the old pinned set up. i found a place in new york city today that has new pins, bushings and all of the other hardware i need to rebuild the rear brakes. again thank you.