Hey, what exactly do different sized pulleys do? How much of a gain could i get if i were to change pulley size? What size should i change to? How hard/easy of a procedure is this? Is it time consuming? Would i be able to do this? Please let me know. Just trying to get a little bit more out of the bonnie.

You will need a pulley puller for it.. it'* really not that hard ( I haven't changed the */C pulley..but have changed enough pulley'* on everything else )

A smaller pulley basically spins the */C faster so it increases your boost.. but @ the cost of more heat and wear on your */C. the more the air compresses.. the more heat it generates which may cause KR.. and the system will retard timing thus reducing power..

Get the intake, exhaust, and 180° thermostat done first, and perhaps a hi-speed fan override. Then go to a 2.2" pulley from www.pulleyboys.com

For the Series 1, you don't need a special pulley puller. A simple 3-jaw gear puller will work fine.

I don't know the exact gains from a Series I L67.

But I know on a Series II L67, going from a 3.8 to 3.4" pulley yields 25 to 30 HP with the proper supporting mods, and way over 30 ft-lbs. of torque.

I'm sure it would be very similar on a Series I engine.