68-70 B Body 3spd wiper/crank arm

Thoughts/experiences needed, more than familiar with the 68-70 B body 2 to 3spd wiper swap with regards to the wiper/transmission linkage being the same, dash wiring the same, 3spd switch required, and of course the 3spd wiper...

Vehicle is a 70 B body, and generally the 2822273 3spd wiper motor arm is recommended, but would a 67-68 B body 3spd arm 2580934, or a 68-69 B body 3 spd motor arm 2587692 be usable?, they all "appear" the same in relation to profile, I have nothing more than pics for comparison, If I had the actual arms, this question wouldn't be needed...lol!

The plastic cam on the 3spd 67-68 (2580934) has a "key/tab" on the outside of the wiper arm crank nylon bushing that could easily be trimmed off, assuming the bushing diameter is the same as the 70 transmission/wiper linkage? the 68-69 B body 3spd PN# 2587692 wiper/crank arm/bushing looks identical to the 70 B body set up (2822273)?

last but not least, would a variable 3pd wiper motor (is the motor truly variable?, or is that a function of a variable switch vs 3spd switch?) function the with 3 true speeds using the 68-70 3spd position B Body dash switch?, I sure someone has swapped/tried these combos out?

TIA,
Mike

The "variable" speed is achieved with a reostat in the switch. All the motors should be the same despite different part numbers and some being labelled "variable speed"

The wiper motor output crank on the 67-68 B-body is keyed and a different diameter than the 69-70. The nylon bushings are also different.
The motors are the same 3sp vs variable. I have never seen a variable switch in a 68-70 B-body as they are rocker switches. You can swap the 67-68 with the 69-70, or the other way around,if you use motor crank and bushings.
When changing 69-70 to a 3sp there is a jumper wire that needs to be added not sure about the 67-68 on that one.

Thanks Bruce, I assume this is the 2 wire jumper you are referencing?

Mike

No that one is for the backup lights. The one you need is under the dash on the switch. There is a thread here somewhere that Jim from J&S was involved with that he posted a pic of the wire. I'll see if I can find it

These pics are from J&S restoration