Supercharged Engines...
I recently bought a 78 440 out of a truck. It is going in my 74 RR that I have never got to drive:sad:
A friend of mine gave me a brand new 671 blower. I still have to buy all the attachments to mount this beast to my engine. Does anyone have any build ideas or experience? I am trying to build a street able monster on pump gas.
So far I plan on electric fan and I want to find an electric water pump and housing (to save some weight) but no luck yet. I would also like a nice roller cam. I plan on upgrading most internals.
RR, you've got the basis for a blown motor, but building one requires several key items and proper planning.
Your compression ratio needs to be ~8.5-1 max, if you plan to run pump gas most of the time, which means you will be limited to about 7-8 lbs boost with steel heads and about 9-10 lbs boost with aluminum heads.
A stock cam and heads work fine but the valve springs will need to be upgrades (under boost, weak springs cannot resist the forced air, which tries to lift them off the seat, which results in pistons colliding with the valves). Also make sure your timing chain is NEW.
The crank snout needs to have, at least, one additional keyway cut to permit you to run, at least 2 keys. This is due to the kenetic energy from the supercharger each time you lift the pedal after accelleration. Failure to add keyways will result in the loss of a crank snout, and will definitely split stock harmonic balancers through their keyways. Ask me how I know...
You will also need to replace the harmonic balancer with a solid billet unit. The stock balancer will crack through the keyway, and many slip the rubber rings just before failure.
You will need the intake with blow-off valve, and matching aluminum studs/nuts. This prevents destroying the engine any time you have a backfire. If the blower 'sneezes' you'll need to check it over anyway, but the blow-off valve and "soft" studs minimize potential engine damage.
You'll need the carb adapter plate, unless your SC has the integrated unit. Decide on a dual or single carb setup.
You'll need boost referenced carbs for a 2 x4 setup, but there are adapter plates that permit a single carb, again that is boost referenced.
You'll need air cleaners, the matching bug catcher, the linkage, and a mechanical advance distributor (vacuum signal is too high with a blower).
You'll need pulleys, sized to provide the boost values listed above.
If your blower doesn't have the idler arm and pulley, add them to the list.
Most BB Mopars take a 1440mm belt, which will run you about $125
Other than the above, you should be in business. Now, if you want to talk ultra high horsepower, then plan on spending a lot more money. The above outline will get you on the road quickly and cheaply, yet you should be able to make an easy 600 hp if you dial it in properly. Good luck.
Southernman
