Technical Flex plate advice needed

I'm in the process of rebuilding the engine in my 31 coupe. I have brought a stroker **** crank part no SC9 103350, 3.75 stroke for my large journal 327 chev 1968 block - 2 piece main seal, bored 4.060, 5.7 inch rods, pistons to suit. My issues is what flex plate to use. **** state crank uses internal balance front damper and external balance flex plate. Do I use a 400 chev external balance flex plate or can weights be added to my current flex plate, my current plate is 153 tooth and 400 is 168 tooth. Will the stater be a problem, I don't have block here to check if its drilled for a angled starter that 168 tooth flex plate needs, I do have a gear driven mini starter already. Anyone who has used one of these cranks in a early 350 would have had this issue, thanks in advance. Glen

 

Just checked my mini starter and it has 4 x mount holes, 1 for each flex plate size, I ***ume I just need a 400 chev external balance flex plate. Glen

 

Are you sure on that part number?????
I do see a **** 103750 3.75 stroke though.
They say external balance, meaning both damper and flexplate are for external balance.

Bill

 

To answer your original question, yes you can add a weight. It might or might not balance the crank properly, and it might or might not provide the correct torque converter position in the front pump.

https://www.summitracing.com/parts/aaf-all26120

I'd rather use the right flex plate...but then again, I'd rather use a shorter stroke crank, but then I'm an idiot.

 

If you bought the crank, rods and pistons separately, shouldn't they (flex plate as well) be balanced as a unit before you ***emble the engine?
Regardless, I'd be asking **** specifically which flex plate you need to start with (it may not matter which one). They should be able to answer that question I would ***ume.

 

Thanks for reply's, **** website and catalog are not that specific so I have contacted them today. I am going to have it all balanced prior to ***embly but would like to buy correct parts to drop of to machine shop. Glen

 

I found out today its the same as 400 chev. Glen

 

If you have the crank out of the engine and have the balancer and flywheel grab your pistons and rods and get them balanced as a unit. then every thing is done right the first time. or do it all over again if it doesn't work