Starter and Casting Numbers

I just recently changed the motor in my 88 1500 pickup. It had the v6 4.3 scotsdale model in it and spun a bearing. Now I have the Astro 4.3 converted into it but can't find a starter that will match up and catch the fly wheel... should i have changed the flywheel also... the starters listed are the same for both models or am i just bolting it up wrong.... and where would i locate the casting numbers to make sure the engine is really what i think it is maybe im just researching the wrong engine.


thanks