I've thinking about putting a paxton supercharger on the 340 thats in the notchback. The 340 engine is .030 over and 10-1 with the current J heads. I have new set of Indy TA heads with roller rockers that should produce the same comperssion but flow a lot better. The cam in motor is a 274/451, which might be alittle small but I don't really what to swap it out. The 340 should be near 300hp currently, and mybe 450 with the paxton? I like the idea of supercharging the barracuda, but I have no experience with superchargers.
Any one put a supercharger on a similar engine?
What's the good and bad on superchargering a stock motor to this hp level?
Any good supercharger forms to check out to help with the decision?
So what do you think, superchager it or not?
I put a Vortech V-1, S-trim blower on my 360 Magnum that was stock except for the (mild) cam.
At the same time I did it, I installed a Chinese (Air Gap copy) manifold and a set of TTI headers, replacing a set of early 340 exhaust manifolds. I used no intercooler, but did put a Snowperformance Boost Cooler on for detonation protection.
No other changes were made.
My RWHP went from 260 to 445. Quarter mile times went from 13.35/102 to 11.60/118. on a very slick strip. With equal traction on the two strips, I am sure the e.t's with the blower would have been more like 11.35-11.40.
So, I picked up about 185 RWHP, 16 mph in the quarter, and dropped my e.t. almost 2 seconds on the same tires.
Those times are for a '72 Valiant 4-door sedan which weighs 3,340 with no driver.
That's a pretty good improvement, but it has its downsides.
Octane is critical, now. Having a set of Hypereutectic (stock) 9:1 pistons is a time bomb IF you let your attention wander and don't attend to the anti-detonation possibilities every minute. Two seconds of detonation under boost will find my pistons in the oil pan. I live under that jeopardy, constantly.
My boost is limited to 10 psi, for that reason.
The fuel system for a setup like this will not be cheap. You'll need a good pump that can produce at least 25 psi, a boost referenced fuel pressure regulator, a blow thru carburetor (mine was $900.00, five years ago; they may have come down since then, I dunno) and about 30 feet of half-inch tubing (a return line has to be included, too.)
You'll need a short-duration, but high-lift cam, that has only about 220-225 degrees of duration, ground with about 115-degrees of lobe separation.
Mine is a Hughesengines grind that is a 214/218 duration @ .050-lift, that provides .525" total lift with stock, 1.6:1 Magnum rockers. I have Crane 1.6:1 roller rockers, but they are not at all necessary.
Gas is always a problem. Unless you want to buy racing gas (or, av gas) all the time, the idea of running a pump gas, boosted engine at anything OVER 10 pounds would be asking for trouble, in my estimation.
The nice thing about a supercharged setup like this is it has a smooth idle (mine idles at 475 rpm and makes 12 inches of vacuum for the power brake booster at that idle speed.)
You don't need a high stall converter; it has big-block torque, just off idle and driveability issues just don't exist.
You'll probably want to look into an MSD Boostmanter ignition-retard unit. They have a cockpit-accessible control knob that allows you to retard the spark 1, 2, or 3 degree for each pound of boost up to 15 degrees, maximum), for running different octanes of fuel.
You're going to need to buy a set of 8.5:1 forged pistons and O-Ring the block to et a good return on your dollar.
Those two things will allow you to run 15 pounds of boost and not worry about detonation blowing your pistons into the pan.
With your new (good) heads, this thing should make 900 HP at least... and probably more.
And, you won't have to run 7,500 rpm to get it.
That's all in just my opinion of course, but I think it should be good for at least that much STREETABLE power... With good-excellent driveability.
A 2012 ZL-1 Corvette would be just a speck in your rear view mirror:blob:
Power is available with good driveability; it's just not cheap...
Good luck with whatever you decide.
