damper size question

I don´t know what size of damper I should use on my 355 chevy smallblock .. Ive tried to search on the engine vin and crankshaft vin but I have no luck ..
Engine vin is 10066036 2 piece rear seal
Thanks / Matthew

 

I like the 8" truck ballancers myself if you have room for it. Remember to use the correct timing pointer for the ballancer you choose. Sometime in the 80s they moved the timing mark from pointing towards the drivers side at TDC to pointing almost straight up. If you mix them up you won't be able to time it with a light. You should probably delete the other identical post you started that asks the same question.