Originally Posted by Ze2222
Now heres the kicker, he says the engine balance is 50oz. Now from researching I found out it should be 28oz.
So herein I take off the oil pan and inspect and can see slugs in the web of the cranks which leads me to believe custom balancing.
So I will be taking his word and i'm using a 50oz flexplate for a c4.
I'm going to run the engine with the trans off. Now will I see if the motor is out of balance. I've never seen one. Or will this be a silent killer? lol.
Basically will I be able to tell if put the wrong flexplate?
My 393 is internally balanced (best decision if racing, imo). If you fire that thing up with the wrong type of balance, your motor will head south pretty quick. What balancer is on the front of the engine? Its technically called a harmonic damper, because it absorbs any engine vibrations produced from slinging around the rotating assembly. Just because there are slugs in the crank doesn't mean its internally balanced, you could have a sh*tty chinese crankshaft the shop couldn't get balanced without mallory metal. If you want to be 100% on it, which you should if building any type of performance motor, disassemble the rotating assembly and take it to a balancing shop and have them determine it. This is the only real way to know, unless you truly trust the guy you bought it from. I wouldn't.
Trust me on this balancing thing. I went through the same scenario about 6 months ago.
1995 Mustang GT
1999 F150 Lariat 4x4
Soon to come: 393 stroker
351w bored .030, Probe Industries forged internals, Trickflow 205's, FTI custom cam, Trickflow R 90mm intake, Accufab 90mm TB, FRPP 42lb injectors, 1 3/4" custom Accufab LT's, 3" exhaust, MS2