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New to supercharging, need some pointers

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Hi, I've been using fuel injection (Enderle Bird) and methanol for many years but I've never had the opportunity to do a supercharged application until now. We've got Duster bodied tube chassis car that weighs right around 2600 pounds. Loose converter, hopefully it's appropriate for the situation, and we picked up a stripped 671 and an additional Bird with the "K" series barrel valve. It's been suggested that it'll need to at least be respooled or just use the cube. We use iron 440 Block, bored and stroked to 500" and Stage V Hemi conversion heads. We'd like to see some low 8s and maybe an accidental 7 would really make my life complete.

I understand that a good blower cam, like a good nitrous oxide cam, is rather specific to supercharging. We have a very aggressive solid roller that I need to see what the specs are...maybe it'll get us by.

My first question to the blower guy was "what compression ratio should we use?" He said that with methanol you can go all the way up to 18:1 but he suggested we'd maybe want to stick around 12:1 and start by spinning the blower 25% overdrive. Fine with me if that's correct.

So those are the question I need to start with, you guys may need more info but I need to start by know what compression ratio will be the most friendly so I can get pistons and rods ordered. We're going to need lots of parts and we also don't yet have a blower intake. So if anyone has some good used stuff we can use, let me know.

Thank in advance,


Compression wants to be high. the way you get there is an argument. I like running static pressure low and let the blower do the work to increase you compression. finial compression of 18:1 might be a little low.

cam is important, however if there is not a bunch of over lap between intake and exhaust, you can try it out. You will want to change the cam at some point.

Excellent, thanks for the response. So you think with a stripped 671 and 12:1 would be a little low? If so how much? Your personal opinion on it is fine. Thanks for the cam info too.


Paul New:
Iím not a Hemi guy but, what I say is 12-1 is too high if your just starting out high static compression does not give you much of a tuning window and you will need it!

we ran 9.2-1 20% over littlefield 8-71 496 BBC on alky 1500 hp on dyno 9000 rpm on the straights using chart gave use 22-1 with the boost.
so 12 -1 seems a high but ran 13-1  6-71 30% over on a drag race 406 small block never dynoed


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