Hi Fellow Hambers, Im trying to figure out wich is the right size Flexplate to my C4 Trans...I've bought a C4 taken out of a Ford Galaxie running a Ford 302 Engine...I know there are two different possibilities of Flexplates one with 164 tooth and another one with 157 tooth...My C4 Trans is gonna be attached to a 1951 8CM Flathead (on my Mercury)...The Ford Galaxie is a 1981 year model made here in Brazil, Im not sure wich one is correspondent to this model in the USA...Does someone have any idea wich Flexplate I should choose?
How are you planning to adapt this trans to your flathead engine? Are you making your own adapter? If you are making the adapter, and not using the Ford bell housing that came with this transmission, you can use whichever flex plate you choose. The main difference in the 157 vs the 164 is outside diameter and the effects the starter location. The bell housing and block separater plate must match the flex plate to insure correct starter engagement. If you want to use the factory Ford bell housing, and do not have one now, try to buy the matched combination mentioned above for either 157 or 164. If you are building an adapter from raw materials, you can design the starter location to match whichever flex plate you obtain. One other important consideration. Small block Ford engines are externally balanced. The flywheels and flex plates are "out of balance" to provide for that. Depending on year and model, the Ford small blocks are either 28 or 50 ounce imbalance. Your flathead engine is internally balanced and used a balanced flywheel. You MUST use a balanced flex plate to prevent a serious vibration in your application. Perhaps you have a machine shop there that can zero balance a factory Ford flex plate. But if not, US suppliers, like Summit, Jegs and many others can provide zero balance flex plates in either 157 or 164 tooth models. Ray
do a search here on adapting a C4 automatic trans to a flathead, lots of info posted.search online Speedway Motors, and others, for adapters and install kits
Do you have the engine and bellhousing that mated that trans. What you are looking for is. Small bell is 5 7/8" long, and from lower bolt starter to top c/c is 15 1/2 , 157 tooth Larger bell is 6 3/16",From the lower starter bolt to top c/c.15 3/4" 164 tooth These are 6 bolt bellhousing There is another way to go is with Flatomatic kit. but you need a mercury half bell 1949 1950 NOTE you don,t want a 302 5 bolt thats early one.
That looks like the big bell transmission. Does the filler go into the pan? The small bell trans had the filler in the case. Yours originally had the 164 tooth flexplate. The small bell 157 tooth trans has a sharp step at the front of the case, not the large smooth flair that yours has. The terms "step case" and "flair case" are sometimes used to differentiate between the small and big bell transmissions.
Doesn't Speedway sell parts and kits for putting automatics behind Flatmotors? There is (was?) a kit called "flat o matic", but I'm not sure what trans, or other pieces it used. 4TTRUK
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