I am thinking about putting a paxton SN93 on a 305 in my 51 Chevy truck. Any suggestions on a carburetor?
The stock carb will be fine but you need to richen the main jet. There may be other mods needed to the float, and to prevent leaks. See if you can find a web site or forum dedicated to Paxton superchargers for more detailed info.
The SN-93 is a centrifugal supercharger that hangs off the side of the engine. To run correctly the carb has to be special built for this type of blow through set up. New they run approx $1000 for one set up with the right floats and seals. You can run a carb enclosure box, which allows you to run a stock carb. Paxton used to sell one, but I believe they were just re-branded Vortech units. You can still buy new Vortech units. Once in a great while, one comes up on ebay but they are usually bid up to almost new prices. If you try to use a standard carb for a blow through set up, you WILL have idle, and drive-ability issues. If you go to Vortech's web site, you can download a manual for a carb enclosure set up. This will allow you to see the hardware and plumbing involved in setting up a centrifugal supercharger with a carb. Gary
biggest problem of not using a blow thru carb is the shafts blowing gas vapor as the blow thru carbs they modify them so they do not leak , there was a book out years back that showed you how to equalize the shafts and also make the adjustments internally needed to do this . Hp sold it . If it was me I buy the box and do it that way . and a square bore style carb is better than a spreadbore ( q-jet or thermobog) in this type of application
Its kind of a pain the first time out . . . I modified a generic holley 4bbl per one of the online walk-throughs that was available several years ago. To run a EV or similar hat (not the paxton box) you need to mill the choke completely off and JW weld up the hole that the rod came though. Switch the power valves to boost reference instead of vacuum and it helps to extend the vent tubes. Oh and change the floats to nitrophyl since the br*** ones can crush. I ended up making 505rwhp/559rwtq with a junkyard Holset H1E off a backhoe (bought on ebay for $80) and a warmed over 302 but it was a one-hit wonder. I had all sorts of problems with it since I cheaped out on everything and some of the chinese parts QC was terrible. The wastegate didn't open all the way and the spring in it was super stiff. First time on the dyno and it spiked up to 15lbs (on 93 no less) and popped a headgasket. Had to machine the seat in the wastegate, find a tial yellow spring, and re-plumb the boost pressure tubing. 2nd time it cracked the E7 factory 302 block . . . Never got it running right and sold everything and went to a 466" BBF with a turbo. Also make sure you run a single-plane intake. Everyone that I know of who ran a dual had distribution problems. The turboforums.com is a great resource for any kind of turbo deal, junkyard/DIY, store bought, etc . . .
ez WAY;mount the carb INSIDE A sealed BOX,psi blower hose runs into box,the bottom of box just goes between carb and manifold= that is so stock carb work as it dose normely,;be sure float is a nocrush type. Studebaker did the Golden Hawks that way.
If it is in a sealed box how does the throttle linkage work? I am a rookie this will my first attempt for a paxton supercharger.
you drill holes for the cables to go thru them a little leakage will not hurt there as its air , nor vapor/air mix
There's a good chance you will have a little leakage where the cable comes in . . . The other problem with the box style is changing jets is a major pain. Very little room to work . . .
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