Here is my 2cents, you can use the large flexplate if you have the matching torque converter(11 7/16). But you must also use a larger bell housing, these are available on several different C4's in many different Ford cars and trucks of early vintage. DO NOT use the 6cyl flexplate, it is internal balanced and the V8's are external. You can use the small bellhousing C4 you have, if you get a small flexplate(157 tooth) from a V8(289-302-351). I can't tell you years and makes to look for because I find mine at yards that have tranny's off and flexplates in labeled bins. Use a tape measure and measure across the bellhousing at the center of the starter hole to the other side. The small bell is about 3/8 of an inch smaller than the large one. I have a large bell and flexplate here and several small ones. The small ones I have to keep for my race cars. If you can, try to get a C4 and Flexplate off of a V8, usually the internals are more beefy than the 6's(number of clutch disc's,drum etc. Whichever one you choose be sure and get the block spacer too. Check out you local Auto Trans parts supplier, new Flexplates are around 45.00 here. By the way, you could still use your C4 off the 6 with the 164 tooth flex off a V8, but be very light footed on that Windsor. Oh yeah, the V8 starters will work on either bell with the matching flex. Nuff said, except I was wondering about this converter that has the ring gear on it, I have seen the Mopar's but not any Ford's, maybe I missed something. Email me if I have thourghly confused you and I'll try and explain it differently. Good luck and keep us informed on progress.