Is an 88 350 out of a truck internally or externally balanced? If it's internal, that sucks... Cuz I gotta return the flexplate I just got from Jeg's.

 

ttt :-D

 

the flex plate has a bat wing weight on it because of the mass removed from the crank when the flywheel flange was changed to round for the one piece rear main seal. a dowel hole was also added t oindex the flex plate in the correct location.

 

I hope that's your way of saying I'm A-OK.

 

The phrase "externally balanced" is commonly understood to mean those designed for use with "unbalanced" crankshafts, such as the 3-3/4" stroke SBCs (400 crank). Sincec the counterweights on those cranks are insufficient to offest the mass of the throws and rods, external mass must be added to compensate.

A one-piece rear main seal SBC technically isn't unnbalancecd, even though the mountong flange for the flywheel or flexplate appears to be concentrtic. Those crankshafts are balanced without the need for externally added mass.

If your flywheel is truly unbalanced, you should not use it on a stock, balanced crank.

 

It appears that Jegs is calling the 1986-93 SBC flywheels "External Balance", when in fact they are not. There were no 400CID engines produced during those years, so they must be erroneously referring to the 1-piece rear main seal as "external balance". Ford drivers...

If what you have is the 490-10-530, it should be O.K. to use on your '88 truck 350.

 

555-60153 is what I got. It's the actual Jeg's brand one.

 

ttt