Which flywheel for T-5 Swap: I have my engine casting number

guys i have just put my T5 worldclass in my 1969 torino 351w, the t5 is from a 87 -93 stang 5.0. i used the 5.0 bellhousing . my problem is that i used the 157 teeth 50oz flywhel at first and the car shooke all crazy in neutral, so i sent the flywheel ,flexplate and the 10.5 clutch with bolts to the machine shop in Alburqueque , he ballanced the stuff and said it was not 100% but it was good enough not to be felt or not to damamge stuff . so yeaterday i put the newly ballanced flywheel on and the car and the car does'nt shake as much as it did before the ballance it's almost zero shake in neutral (almost),but when i drive it, boy it shakes and vibrates everything.. can someone please help me here i am out of money and ideas, the shop was talking about bring the crank and stuff over which is more than i need right now. the flexplate i sent in together with the flywheel was from the fmx automatic
i must say though that the T5 really feels awsome when mashing through the gears . i am almost at the point of driveing my car guys please help

I'm not 100% sure but you may need to bring in another 157 tooth flywheel to let them match balance your's. The slightly larger (164 tooth) FMX flexplate may have had a slightly different weight.

Here's a low cost and simple solution to your problem. This is the FW (Click Here) I purchased for my T5 swap and it sounds like it will fit your needs. Hope this helps.