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Paxton supercharger on carb`d 70 Mustang

12K views 18 replies 16 participants last post by  Hawk56 
#1 ·
Hi to all. I friend of mine just gave me a Paxton supercharger he had on a 90`s fuel injected Mustang. I have a bone stock 70 Mustang 302 and I want to install this thing and see how long stock pistons can live under boost. I been told I must get a dedicated carb for this and I been told I can put a "normal" carb inside a pressure box. Somebody also told me I can use a hat for the carb and thats all. What do you people think?

Thanks in advance!
 
#2 ·
Recalibrate the carb for forced induction. My freind used a AFB in a box for his 289. Cast pistons will last, so will hyper pistons, but use a msd btm. You just have less margin for error.

A 289 toploader with a paxton and 4.10's is a little terror.
 
#4 ·
In 1957 and again in '58 Special Order Ford racing cars (both T-Birds and some sedans) came with a Super Charger on the 312 Y Block V-8's. They went out and did some serious Trophy winning too in the west. I even saw one on a factory Y-block 332 V-8.
Normbc9
 

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#9 ·
Blowjob

Studebaker owner of McCullough (Paxton) always used blow thru carbs mounted directly on intake manifolds mostly in pressure boxes a few Avanti pressure carbs . ALLWAYS with pressure relief valve on top of carb in case of backfire ! You do not want a pressurized fuel /air mixture backfirng thru the blower ! That reason NIXES suck thru ! 8.5/1 pistons worked fine for them but all their v 8s had forged crankshafts .
 
#10 ·
I'd say that you can run stock pistons and rods, but not bone stock.

Factory assembly clearances are not supposed to be exposed to excessive temperatures, that you meet in turbo/supercharger applications.

I mean, the piston ring gaps are too small for that much heat. And even if your pistons can withstand the heat, it's the rings which would expand, eliminate the gap and then - bang! - you get either broken ring lands or scratched cylinder bores.

You can run that Paxton with stock engine with a bit rich carb tune up (too cool pistons), until you won't pull it hard.

Proper clearances differ a stock engine from a race engine in a bone stock class.
 
#14 ·
If you have the carburetor box, I'd go that route. The Paxton set up was an option on the 66 Shelby. I had that setup on a 66 Hi-Po Mustang. I think it might have had 6 pounds of boost, maybe 8 pounds. One problem I had was with the fuel pump. Don't remember whether it was on the Mustang or a 57 Studebaker Golden Hawk I had. The Hawk came stock with a McCullough supercharger. They were later bought out by Paxton. Anyway, I had to run a pressure line to the pump because when the supercharger reached a higher pressure than the fuel pump it would shut down the fuel flow. I only bring that up because it was something that took me awhile to figure out.
If you want to go without the carb box, I'd google info on what you have to do to the carb to be blow through. I know the Studebaker Avante didn't use the box with a supercharger.
You'll notice quite an improvement in torque and all around performance.
 
#16 ·
A friend of mine put a Paxton on a 1971 Duster 340. He had quite a few problems with it. The box (new) kept leaking around the grommets where the linkage went through, the floats had to be replaced with fiberfill floats because the pressure crushed the brass floats, and the carb had to be rejetted very rich to handle the extra air when under boost so it was too rich when he was just cruising. Other than that, with 10.5:1 compression ration and boost limited to 5 psi, it ran great (almost as fast as my 1970 Duster 340 with a cam). All this was on 100 octane gas. My suggestion is to go to a junkyard and buy a 5.0 Mustang fuel injection setup. You'll avoid a lot of problems. My friend finally took the Paxton off because it was too much trouble to maintain the leaks and bad gas mileage.
 
#17 ·
this web site will help you with all ur needs and questions about blow thru carbs..

http://www.theturboforums.com/threads/299573-THINKING-ABOUT-GOING-BLOW-THRU-READ-THIS-BEFORE-POSTING


I'm running 12lbs of boost in my 68 mustang, engine is far from stock. Dont forget that you will need a bigger fuel pump & boost referenced. This site can teach you how to convert a holley into a blow thru carb. It's a chore to get the engine tuned, but i did mine all by myself.. and let me tell u.. its a fun ride when ur in boost.



i've been running this setup for about 2 years and its been trouble free and low maintance. Very dependable after you work all the bugs out.
 
#19 ·
I have been running a McCullough VS57 supercharger on a 340 horse 327 Chevy for about 5 years . In a
56 Studebaker Golden Hawk . The first thing I did was lower the compression to about 10 to 1 , I cut
the domes off the stock pistons to make them flat tops . Z28 hydraulic cam , I am using a highly modified
650 Holley double pumper in a blow thru application . The VS57 has a variable pulley . At normal speeds
it puts out about 2 lb pressure , it has a electronic kick down that opens the pulley and the pressure
goes to about 9 -10 pounds , this is adjustable . The fuel pressure problem was solved by using a stock
fuel pump and a electric pump set at 12 pounds . Under low pressure driving the stock pump gives it about 6
lbs of pressure , under high pressure the electric pump goes on with the electric kick down . A check valve
keeps the fuel from back feeding the electric pump and the stock pump phase one build in .
With a Muncie M21 and 4.56 gears it a fun ride .....
With a Paxton the box is the easiest way to go
 

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