General Motors made no less than a gazillion different starter combinations over the years.......Each parts store chain does not necessarily carry the same line of reman starters..NAPA fo example does not require their owners to handle any specific brand...They usually have more than one price range...from cheap crap to somewhat better...FORGET about the GOLD PLATINUM LIFE TIME WARRANTY CRAP..!!...There is hardly any difference but the price...Find a counter guy...preferbly a guy that HAS worked on more than one car EVER.!!...Keep looking...Theres one out there somewhere near you...Ask how many of so snd so brand have they exchanged in the last...say.....two days...If its more than one in the last thirty days...then forget it......If ya find one that sounds OK look at the end of the drive..It has to say ."5 ROLLER."....If not give it back.....When ya get home with one ya finally decide on.....check the flywheel/flexplate......there has to be good teeth...V-8s tend to stop in two different places about 180 degress from each other....Roll the crank 360 and look at all the teeth...Every guy has his own theory on the amount of teeth left...There is going to be some wear...You decide....My project engines all get new ring gears/flexplates..not new used..NEW.!!....NEXT...remove the solenoid....Bolt the starter to the block.....This way you can engage the drive into the flywheel...Take a paper clip and straighten it out....Heres your gauge of .32 or what ever the book says...Fit the wire inbetween the teeth....Keep adding shims (the thinnest first)..untill the wire has a smooth fit....While your under there do make sure the drive is engaging a full tooth...The drive housing can not rub on the flywheel either...Use new mounting bolts....I buy mine from the Chevy house...Not offshore crap................................................................................................ ...........FoMoCo starter motors.....Same thing almost....flywheel teeth...5 roller drive....Ford uses Delco in their heavy duty applications....take it from there....