Ok i have an 86 camaro with the 2.8 that started knocking. And i want to swap in the 3.1 v6 chevy motor i have from a 91 isuzu Rodeo. The problem is the car has a manual and the 3.1 had an auto behind it. I have been told the that they are balanced differently. Is this true? the 3.1 is supposed to be the same as the 91 to 92 camaro engine. I plan on using just the long block assembly from the Rodeo and want to make sure that the the intake and everything else will bolt up.

And if i need a 3.1 liter specific flywheel does anyone have one i could buy for a reasonable price?

 

your sources are correct.

the 86 2.8 engine is externally balanced.
the 3.1 is internally/self balanced.

not sure if anyone here has some extras. Could get new from parts stores, or try car-part.com, and search for 91-92 3.1 camaro one.