rocket 5979 said:
Yes there are differences with stock engines. There are differences with modified engines. But with a modified race engine you will want as little stress as possible on the front of the crank or anywhere in between. If your going to be getting a 347 you should be revving it high to use the power and breathing it should have. So it would only be logical to get an internally balanced shortblock or have on balanced after you buy it. Putting a damper on there is an ok cheap fix to a simple problem for stock cars. But for a race application you will want a properly balanced engine from the inside out if you will realistically expect it to last a decent amoung of time. Even if the fella was to get an engine setup for a different balancer it would be no big feat to get a different balancer for that engine. Or order stuff for a mustang 5.0 with the 4R70W tranny and pull the plate from that. It is still no big deal to swap em out. In the scope of what the project would be that would be a comparatively very minor detail that could be ironed out in spare time.
I thought someone mentioned using a FRPP shortblock. It is already assembled and balanced for use with 28oz damper and flexplate. The only reason to buy a shortblock is to short circuit the machine shop stage - basically a quick solution. There is no reason to buy an already assembled shortblock, then pull apart and re-balance.
As for dampers, they are not cheap fixes. All V8 engines need dampers to dampen out harmonic vibrations due to V-Angle and firing order. There are only two engine combinations that are "perfectly" harmonically balanced - I6 and V12. (H6 engines may, but it has been ~8 years since I was involved in engine therory, so can't remember for sure.) All other engines require a damper to reduce the harmonic vibrations from the firing sequence. Even on a 0oz imbalance, the damper is a critical component. A Romac, or similar high quality damper is always used.
Now, as far as zero balance, you need that for high RPM running. If you are going to be using an automatic, you will not be high in RPM, due to torque converter limitations.
I am building a 349ci stroker for my Ranger right now. The only reason I am balancing to 0oz is for re-sale of the short block. It is a Boss 302 block, Trickflow crank, Oliver rods, and Ross pistons. This will make a great combo for me as well as mustang racers. If figure if I decide to go to a 351W based stroker in the future, it would be easier to sell as a 0oz balance, as anyone spending the kind of cash on this would be probably drag race high RPM.
In order to run other than 50oz imbalance with the explorer engine, you need to do several mods. The explorer damper is one piece assembly of the damper, DIS exciter ring, and crank pulley. In order to run the explorer acessories, you will need to get a 28oz or 0oz damper and have a machine shop make an adapter to run a 94-95 mustang "GT" (not cobra) crank pulley turned backwards and adapt the Explorer DIS trigger wheel on the front side of the crank pulley. Also need to make a spacer for the crank sensor to move out to meet with the trigger wheel. Finally need to get a Powerdyne fan spacer ($85) or run an electric fan to provide running room for the trigger wheel forward of the crank pulley. While this is no rocket sience, it is not something you are going to turn around in a day or pick up at the speed shop. All Custom. I have gotten a Romac 6.2" OD damper and have completed about 75% of the parts necessary to complete this stage. One spacer for the sensor, two piece pulley/trigger adaptor, with roll pin locator for the trigger and shuffle pin locator for the adaptor, requiring drilling into the Romac. A machine shop would charge at least $200-300 for this work, based on time involved.
I am shooting to have this done by May, as a bunch of the Ranger V8 guys are planning to meet at a drag strip for a grudge match somewhere in Ohio, VA, KY area in May.
