Hi. I am doing a l6 to 302 swap and now i`m missing a flexplate cause the one from the 250 wont work. The engine is supposed to be from a -68 mustang and the c4 from a -73 comet 250 cid four door. I have read from other posts that the imbalance should be 28 oz. Here is a picture of a flexplate that was bolted to the engine when i bought it, it's a lot bigger probably a 164 tooth for some other tranny. http://www.kuvaboxi.fi/mediaobjects/orig/pub/2008/04/05/8143010478537494272orig.jpg So the question is does that look like a 28oz imbalance. And are there other issues i have worry about. Here is a picture of the engine. http://www.kuvaboxi.fi/mediaobjects/orig/pub/2008/04/05/8143010478537494296orig.jpg I would say it's a small bell and everything else should be fine because it's a complete package just bolted of the 250 engine.
yeah should be 28oz the size depends on the bell housing of the tranny some C4 have big bells and some have small bells make sure you get a small bell housing flexplate witch will probley be 154 teeth
157 teeth on the small ring gear and 164 on the big one. The small bell won't fit over the big ring gear - if you use the big bell on the small gear the starter won't engage properly if at all. If your engine is 28 oz imballance then the flexplate has to match - if you have the 50 oz. imbalance engine then the flex plate has to match it. You can usuallly go be engine years but you can be sure by checking the hamonic balance number to find out what you have.
The engine should have a number on it that starts with C8****. that would be a 68. C9=69, D0=70, etc. 68 was 28 oz. balance. If you have a 164 tooth flexplate you have to have the big bell, and motor plate to match. Also the Torque convertor. Same deal if you have a 157 tooth flexplate. You would need the small bell and motor plate and the smaller Torque convertor. Also remember that if the tranny is a 73 c-4 and you need to order a convertor that it has to be a 26 spline. they changed fron 24 to 26 in 1970.
