Procharger pulley size question...

[6D9]

Anyone know appox what size blower pulley will be needed for 6-8 psi boost in a 408sbc???

Thanks

[camcojb]

406 with D1SC, very good heads, etc made 14 psi at about 6400 rpm with a 3.85" pulley. Each 1/8" in pulley size is approximately one psi of boost. In this case a 4.75" pulley should be close to 7 psi or so.

Realize there are many variables that will change the above. Airflow through the engine, cam, exhaust system, etc. will all change these numbers. That's my best guess, or "shot in the dark".

Jody

[6D9]

Thanks Jody. Like I told you in the PM I have a 4.38 and you felt it would give appox 10 psi with my combo. I just wanna be conservative out of the gate with it and not stuff 10 psi right away. Should I just put the 4.38 on and keep the rev's down at first and see what it does??? Or just get the bigger pulley and tune from there?? Thanks for all your help!

[camcojb]

Thanks Jody. Like I told you in the PM I have a 4.38 and you felt it would give appox 10 psi with my combo. I just wanna be conservative out of the gate with it and not stuff 10 psi right away. Should I just put the 4.38 on and keep the rev's down at first and see what it does??? Or just get the bigger pulley and tune from there?? Thanks for all your help!

pretty simple to swap pulleys, so I'd try what you have and see where it ends up. It may be close, just be sure to keep an eye on your boost, timing, a/f, etc. when testing it.

Jody