Ok ,bigblock bryan didn't say anything about a starter, just the bearing retainer ring. By that I would think he has the smaller retainer and a bigger hole in the bell housing. I guess I would like to know how you cracked the bellhousing trying to install the transmission? Did you replace the clutch disc and not use an alignment tool ,then try to pull the bell housing to the block? Installing the trans with out the centering ring will not center the trans, the bolt holes are not tight enough to do that, you will have a off centered clutch disc and it will shake the heck out of your car. The ring and the bearing retainer are a tight fit. Another thing you state that bolting the trans to the bellhousing and installing it. I don't know how others do the trans install but in 50 years of putting in 4 speeds I have always put the bell housing on the engine then put the trans on the bellhousing. That is if the engine is in the car. Dialing in the bell housing: I didn't do it for years, Luck ? probably, It's easy when you have the proper tools, a hoist , a helper to rotate the engine while checking runout, then if needed, ordering the correct offset dowels from McRobb or is it robbmc? and doing it again hoping you got the correct readings the first time. It's not rocket science but sure is a pain in the butt.