its 157 tooth and go to fordracings site they have one , its what i used when i put my 351w in. its sfi certified and just what you need. good luck. so what you need is a 157 28 oz manual trans flywheel.
I bought my sfi steel flywheel from center force. It has worked great. Basically you are running the same tooth count as the 5.0L because you are using the t-5 tranny bellhousning. You would not get your starter in if you went with the larger flywheel.