Supercharger unit

[reaperz1]

I have a 1972 Chevy 402 bb that is 30 over and I want to super charge it. I have experience with turbos but little with superchargers. I want to know what sizes would work and brands. I will be fabricating some of the mounting kit. Also places where to look for a good used and refurbished one. It is in a 1972 Chevy c10

Thank you
Josh

[Domer]

are you looking at top mount roots style? or a side mount like vortech and paxtons?

[BigDan3131]

So the motor was built to supercharge it? Low compression like 9:1 or less with forged pistons not cast or hyper? A cam for supercharger use? If a roots style I would just go with an 8-71 instead of a 6-71 which takes less boost to make the same power. Depending on the cam and rpm range a pair of not less than 650DP's built for supercharging. Unless you have the bucks for a FI system.

[pacman1967]

I have a 350 bored out .040 with a Weiand 142 making 5lbs of boost. I built my motor around this supercharger. Cam selection is huge and everything needs to be forged. As far a finding a refurbished one, try the blower shop or dyers blowers. If you go with the bigger 6-71 or 8-71 be ready to drop a good chunk of change on some carbs. If you just want to go with a smaller single carb a Weiand 177 is a great choice. My buddy had one on a 454 and make 7lbs of boost.

[Domer]

I'm running a 355 with a 6-71. I have a forged crank, h-beam rods, and 10cc dish hyper pistons. World sportsmen 2 heads with 76cc, and dual Holley 750 double pumpers(boost referenced) making 8lbs of boost. Im running a big blower cam, with long tube headers, and a t56. Mine is just a street machine. For the big block I'd run a 8-71, or a centrifugal side mount. The mini blowers make a lot of heat.
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[Hollow65]

8-71 will run cooler than a 6-71. I run an 8-71 with dual Holley 780's. Any blower won't be cheap. You'd rather be rich than lean on a blower. I would splurge on a new blower also. Who knows if the previous dude maintained his stuff. I went with bds, good tech support from them. I'm not sure about other brands. I've been torturing my truck for 16 years. Do some strips on the roots once in a while and make sure it has oil in it.

You will love the instant torque, the boost kinda builds like a turbo on the bigger blowers.
My sbc made 630 ft/lbs @ 2300rpm, beware of the random lane changes under acceleration.

[reaperz1]

Sorry for delay been working long hours. My engine is set up for blower except for carb and cam shaft at the moment. I am interested in a centrifugal supercharger like the procharger. I like that there tuck away and do not have to cut the hood. The truck will be eventually a daily driver to work for a while as well

[BR3W CITY]

A procharger will require you to run a blowthrough carb, which itself will run $750-1000 for something like a CSU. The cam is easier, since there are so many companies spec'ing and offering blower friendly cams. You will want to make sure that you run a valve spring with enough seat pressure (duals and beehives are popular for this reason, your cam maker should be able to offer a pairing for the cam combo).

How is the motor set up for boost? Like forged internals/built heads and wanting to run something like a procharger F1...or something a little less beefy looking to run the "regular" size P1 or D1 unit?

Those prochargers are the most common on chevy's at the moment. You can still find some Vortech kits for the sbc and bbc, but they aren't as common as they were 8-10 years ago.

You'll need to decide how many pulley ribs your going to run (or cog it), then get the belt drive and pulleys needed to run that size. 6 rib is the basic one for the smaller blowers, but also can slip the easiest. Depending whats available for your bbc, you may be able to run 8 or 10 ribs. More ribs=less slip and more boost on a smaller pulley.

With any of them, if you build the bracket, you'll need to engineer to it achieve enough belt wrap. Belt wrap is the amount of belt contacting the pulley, which you want to maximize to avoid slip. Its gotta be WAAY more secure than a regular vbelt tensioner. With that being said, its usually not a matter of cutting some stock and making spacers. Most of them are machined or fabricated from thick aluminum, but steel can be made to work if you don't mind the weight. No matter what you choose, it needs to be able to properly align and brace the blower unit, and guide the belt in a manner which allows it to have full contact on the pulleys (belt wrap). Its doable, but a bit involved if you haven't tried to do it before.

There probably is a BBC bracket available if you choose to go with the procharger, you'll only have to deal with where they choose to mount it. They aren't cheap, but they are engineered to work.