C4 experts, need an I.D.

[Vanspeed]

From what I have read this is a pan fill c-4. I believe it is a '78. I am putting this behind a '71 302 for my f-100 project. My engine was originally manual trans so I have no flexplate and I have the wrong mid plate I was told. What is the correct flexplate for this trans? I am thinking it is a 164 tooth, 28oz. plate but want to make sure before I buy the wrong one and damage the engine.

[darrell]

thats the one you need.ford changed the balance in 81.this flywheel is also used on the fmx trans.

[deucemac]

If my memory serves me correctly, it was 1982 for 28 to 50 oz. balance change. It appears as though you have a big bell C4. They were popular in trucks and vans when the larger torque converter was used. You should be able to use pre 1982 parts for either van or F150 to make an easy conversion. A local trans shop can help you choose the correct components. Just take the old flywheel along so they can see which balance the engine had. You will know if you get the wrong flex plate because you fillings will want to fall out at speeds over 55 or so. Been there and done that on small block and 428-410/390 FE motors but only once each. Good luck.

[Vanspeed]

How do I know the balance of the engine? Count the teeth on the flywheel and see if it matches? I know the engine has never been apart.

[1931flathead]

There is a date code on the engine

[1931flathead]

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it should have a D8 on it to be 1978 on the block and heads and intake and exhaust manifold

[5851a]

Balance weight matches engine and flex plate matches bell housing. So 1971 is 28oz and pan fill C4 needs 164 tooth. Also the block plate for the transmission has to match bell so the starter lines up. I have a 78 F150 with 302 and C4, little shy on towing a big load but a fantastic combination for all around use.

[Vanspeed]

Got the correct 164 tooth 28 oz. flexplate and correct engine plate. Thanks for all your help.