Anyone ever run a supercharger on a 351C?

[767Jockey]

This idea just popped into my head today. Instead of spending 10K on a whole engine rebuild, what if I just put a supercharger on what I already have?

My 351C is essentially a stock 1972 block and bottom end with open chamber 2V heads. I poked around just a bit on the net but didn't see any 351C supercharger kits. I admittedly didn't look real hard, but it's readily apparent that the kits for this engine aren't a dime a dozen. Do any of you run a supercharger? Any ideas, where to get info, engine suitability, places to get expertise, ANYTHING to lead me in the right direction on this? What kind of power can I expect to see?

I don't know if I'm going to do this, but the idea is intriguing enough for me to pursue it a bit. Thanks for any and all info.

[olddog]

From what I have studied (no first hand experience) any type of forced induction has the problem of heating the air. The less efficient the blower the more waste heat added. On top of this waste heat, anytime you compress a gas you increase the temp. This is why you will see after-coolers to bring the air temp down before it enters the intake.

If you run at mild boost level say 5 psi, you can get by without the after-cooler, as long as you do not have too much compression. Air at 70 deg at sea level is at about 14.7 psi (I'll round to 15 psi). So 5 psi boost is about a 33% increase in air density. So, your engine would gain about 33% more HP minus the HP used to drive the blower. This is an ideal case that you will not likely achieve. Also since you increased the density of the air by 1/3, you have affectively increased the compression ratio of you engine by 1/3. So, a 9:1 compression engine would act like a 12:1, as far as the air temp in the combustion chamber at TDC on the compression stroke. Therefore, you have to pay attention to the compression ratio and the air temp exiting the blower, or you can get into pre-detonation quickly.

At high boost levels intake valves can actually be pushed open. So, going high on the boost gets more and more technical.

Multi point EFI is much better suited to superchargers, but carbs can be used.

[cobrarkc]

Just to add to that the 351c open chamber heads are actually more prone to detonation than the quench ones are which opens a whole new can of worms. If you go with the quench heads you will need a custom dished piston to get the compression down to 8.0 or 8.5:1 so you can run a decent amount of boost, aluminum heads will allow you to run maybe one more psi. To get back to the supercharger question, no one makes a specific kit for the 351c so you will have to buy one for a windsor engine and have a custom bracket made and then there isn't enough room to fit one in the Contemporary body without modifying either the body/engine compartment or hood unless you have some really trick bracketry made. I wouldn't let this discourage you because anything can be done. It will make a smoking motor.

[Bill Wells]

i put a 1960s era paxton supercharger , rebuilt to vr-4 racing specs, on my 351W in my spf .

see pics in my photo gallery .

space limitations are a concern. it is not a cheap addition . the engine should be built specifically to be blower friendly . there is a lot of custom fabricating that has to be done ; bracketry, pulleys, shims, spacers , air ducts, different msd ignition system, rebuilt carb for blower usage, specific pistons for blower friendliness , maybe a different fuel pump yadda yadda yadda . it aint cheap to do . I am sure the same cautions and space limitations apply to your cobra brand and the Cleveland engine.

I would caution anyone doing it that thinks it is a bargain, ie, not expensive and does not have an engine set up for it .

after 3,000 miles my engine blew : top of 3 pistons digested by the rest of the motor, top edges of 3 others gone . valve damage . heckers, parts blew out the exhaust pipe ! autopsy : too much boost, too much compression and wrong engine internals ( the engine in the car was not what it had been represented to be ) .

however, the kick when the pax spooled up was unreal, the sound was like a F16 fighter jet and the eyeball appeal was great .

I replaced the blown engine with a ford racing crate stroker and left the blower off - decided it was not worth the hassle to rebuild the old one to blower specs as summer had just arrived and i wanted to drive and not have the engine out . so i was 'blow to go' in 7 days with a new motor instead .

there are several blower applications for 289s and 302s that are virtual bolt on kits - same with 4.6L mod motors . I am not aware of any 351 bolt on kits - none avail when i did mine . however, some of the 289 kit parts can be used .

for now, i have pleasant paxton memories and wait til i decide to go 'back to the future' and do a repeat - but the right way this time . Good luck . Bill

[cdmford]

yes have a 671 sc on my 92 fox 351c 2 750 dp i love it .030 over domes pistons she is fun injection is nice but i would rather be blown