Another 302 ID question.

[Talley-Ho]

I have an odd one here, hope someone out there has the answer.
Purchased a 77 mustang recently with a 302 in it. It has a T-5 transmission that according to the salvage yard markings is from a 93 mustang. The bell housing and starter appear to have came with the trans.
I assume then that the flywheel is a 157 tooth 50oz counterweight unit. I know that a 77 302 would be the 28.2 oz

It has a slight drive train vibration, but not as bad as I would have thought it would be if it needs a 28.2oz counterbalance.
The guy I got the car from had owned it about 6 months and had not driven it a lot and had no idea about what was done to it prior to when he purchased it.

Long story even longer, I pulled the started to check the casting # and low and behold no casting number, the ridge where they go was not even there. There was a date code there but it was running vertical to the crank in lieu of horizontal with the crank.
2D24,- 2nd year, April 24th. But without a casting code I have know idea of what decade. Checked all over the block but found no numbers any ware .

Anyone ran across this before? I really don’t want to pull the engine just to get the pan off and get the numbers off the crank.

[93CobraR]

When is the vibration accuring? On acceleration or deacceleration, idle??

[Talley-Ho]

mainly on deacceleration