Re: Blower combo for 302 windsor
Lot's of variables here. Maybe you can clarify a few things for us. in order to help you better.
What gearbox and diff combo are you using?
What type of fuel do you intend to run on?
Will the car remain as a daily driver or just a weekend racer?
Pros and cons for different blowers as well are as follows:-
6/71- style look awesome, but less efficient and make heat, so boost is limited to around 8-10lbs, they make very good low down power and torque
Centrifugal- can make the most power, but are essentially belt drven turbos, and make only modest power/torque increases down low, great for dyno horsepower competitions
Twin screw- make as good/ better low down power than a 6/71 style, are as mechanically efficient as a centrifugal, style of blower used by top fuel teams
Cam specs are detemined by your head flow.Remember, a blower will smooth out a big cam, so you may not need to go 'smaller'. You may need to change the profile however, to allow the extra fuel burnt to escape through the exhaust
Lower compression theoretically allows you to run more boost and more ignition timing, but again, it relates to the fuel you are using. Guys running 6/71 style blowers generally run lower comp (around 8.5-9.0:1 max), because of the heat they produce and the tendancy of these motors to ping.
In terms of flow, the other guys could tell me what the AFR's flow, but let's say the flow 270cfm on the inlet, then you'll need roughly 8x 270cfm through your throttle bodies. So, as a rough estimate, i'd say your top hat is a bit small.
Get back to us with those questions at the top and we'll be able to give you more accurate advice.