383 Timing

Could use some input from people concerning the timing on a 383 that I'm running. Recently installed an MSD distributor on the motor but had to find TDC before doing so. I ended up setting the motor at 12 degrees before TDC. Got the motor to run and made some small adjustments to the distributor to get it idling nicely but when you check the timing now it shows that the motor is idling at 28 degrees. Running the motor up to 2500 rpm and it advances up to 50 degrees.

I acquired the car from someone else and in consulting with them the motor used to top out at 38.

Any thoughts as to why the timing numbers are so different? Did I not actually find the right place for TDC and am not compensating for it with these high timing numbers?

Thanks for the help.

So you didn't actually verify that TDC was exactly TDC as marked?

Did you have vacume line connected when checking timing wit light????? vacume connected would probably show it pretty far advanced-------also, if you subtract that unverified 12 degrees , you are at 38* so maybe your dampner is off ??????

also would be 16* at idle------28-12 =16