I did a search on the big block valve cover to wiper motor clearance issue and came up with one question.

Can I spin the wiper motor 1/3 revolution, only using 2 original holes and redrilling for the 3rd. I'll have plenty of clearance if I do this. It will rotate the stud on the motor down closer to cowl "floor" (for lack of a better word.)

It doesn't look like their would be an issue of the rotating lever hitting the bottom of the cowl "floor".

Has anyone done this and succeded?

And are 67 & 68 motors different? I thought they were the same.

You can spin the motor, and all will clear on a 67 Camaro. The 67 motor has a rounded rear case, while the 68-9 is more oval shaped- The hole in the firewall matches these shapes- 67 is round,68-9 is oval shaped. See pics

Its important to see if you can rotate the oval shaped 68 unit within the firewall- Just visualizing,but it seems like it'd be in there upside down. A 68 and 69 motor will interchange,but a 67 will not- it is unique. From your question, not sure what year car you have,but I'm guessing its a 68?

67 Motor rear:

http://i22.photobucket.com/albums/b339/belairbobs/67wiperrear.jpg

68-69 Rear of motor:

http://i22.photobucket.com/albums/b339/belairbobs/69rearmotor.jpg

Wouldn't the wipers park in the wrong place?

Maybe, but then you'd just need to pop the wiper arms off and rotate them to the right spot. The motor parks at the same place every time,no matter how the motor is rotated,but the wiper arms could be slightly out of synch..true true.

Wow, I learn something new all the time. I thought 67 & 68 would've been the same.
Mine are 67's. The holes on the firewall are 4 1/2" apart except 1. It's at 3 1/2". So it can be indexed properly I assume.
If I spin it, the washer nozzle tips would be pointing up at an angle towards the hood hinge.

That would drop the shaft lower, but hopefully not too low. Then I would have see how it's going to make the arms react. I'm not sure how it would affect the "throw" so to speak.

Thanks for the pics. Bob.

I think I've talked to you before on a chevy site a few years ago about a 57 chevy.

Detroit Speed sells a modern (small) motor with adapter plate, it's even intermittent, comes with a wiring harness, with a proper looking knob on the switch.

You could make your own adapter plate to save money, and 88 GM pickups had a simpler two speed motor.
David