Actually I read through, and I had it backwards. I'll be reducing the crank pulley, and increasing the SC pulley. Hell, I'd be building a bomb vice-versa!

 

Leave the main drive pulley alone. A larger one wouldn't fit anyway. Get a larger SC pulley like a -7 or -6. They don't recommend a -6 unless the -7 is allowing too much boost.

I assume you have a 7" SC for your 12A. Those usually came with a -7 or -8 pulley.

 

Yessir, 7 incher. I got the pulley off, and it's 3.5 inches, so this was already putting out obscene boost. You think a 7 pulley would put it @ about 4 psi?

 

Look for a number with a dash in front of it like -8 or -7.

My brother's 5" SC came with a 7" pulley and the boost came in very late and was very low for a 5". It had a -7 on it. This is wrong for a 5" SC. So I got a -9 from a guy on here called 84stock. I didn't want a -10 as those come on too early and run out of breath too soon. The -9 seemed to do the trick but I would not recommend that for a 7".

Get a -7 or -6.

 

Yeah...I guess this was a custom pulley, cause there isn't any identifiable marks on it. I guess I'll have to find, or make one.

Camden doesn't seem to have listed the pulley bore, or shaft size. Would you happen to remember off the top of your head?

 

You could call Atkins Rotary, they are the ones that own camdon now. Use the number on the camdon Web site there very helpful