pulley size question. need your specs!

i am in the final stages of my build up on my 69Z. its been a long winter. converted from auto to 4sp and built a $$$ bullet proof shortblock. getting ready to put the blower on, but i am making a change since my initial investment last year. i decided to go with an intercooler now after a nice tax return. :-)

when i gave procharger my specs i told them 14-15psi. they sent the D1 with a 4.25" pulley. now i would like to make use of the full power available from the D1. 4.25" pulley at my shift point of 6800-7000 would spin it around 55k. i was debating on going to a 3.70" or maybe even a 3.40".

what size pulley are you running? what are some quick engine specs? how much boost do you see with your combo?

anyone "slightly" overspin the D1 past the 65k?

any help appreciated.

thanks,

mike

Mike,
I'm running 7.5" crank and 4" sc pulleys on my D1-SC. This is making 15 pounds at 6000 rpm on my 306, I'm at 5400 ft. elevation though. Remember that you will loose a couple psi with an intercooler, which i'm not using. Hope this helps.

Brian

I run a D1 with 3.85" blower pulley on my 358 SBC. I'm producing 19psi near 7000rpm. I don't recall the blower speed but, it was real close to redline.

I think you'll need to run another idler on the underside if you wish to run a smaller pulley. Otherwise, belt slippage could be an issue.

i do have a second pulley which i will install on the bottom side of the belt. thanks for the tip.

mike