Flexplate dilemma

help....can I use a flexplate from a 79 351W on my 69 351W motor....I understand that all 351W before 81 us a flexplate with a balance of 28.2 oz....but I'd like to heare from the real guys who have done this...I'm mating a 85 AOD to the 69 motor...I boughta junk 351W from a 79 Cougar for parts, cause I stared with just the 69 motor and crank (bare block)...people said this was the good block to get...(I won,t be doing this again)



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I ran into similar problem but with a 302

motor. Some one changed engines on a 1979 f150 and it shook. He went to the local ford

dealer and was told it was the harmonic

balancer. After paying $200 for a new one and

installing it the shook was still there. I

bought the truck ($500) because no one would

once they drove it.

I then researched the flexplates and

found out 1978 down was one part number,

1979 was another and 1980 up was a thrid !!!!

Check with a ford parts house on the

351 but make them look up the numbers.



Jack



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thanks for the rereply Jack...I did check with the Ford partsman, and he told me he had noway of checking to see if the were compatible (like if the parts no. matched)he couldn't even come up with a part no. for the 69 motor...but you know what??

the flexplate I do have (79), has no numbers at all on it !!!..so I can't very well compare part numbers anyway...hope someone has the answer...thanks



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Well, since you are starting out with a mixed bag of parts (and yes the '69 block is a good one, with a slightly lower deck height)just go ahead with your project and have it balanced, flex plate, dampener,and all.



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What year is the crankshaft? the year the crank was made will determine the flexplate you need. The 302 and 351 uses the same flexplate up until mid 78 then in 79 they used a different balance. The winsdor used a 28 ounce imbalance until mid 78 then went to a 50 ounce imbalance in 79. You will need a 28 ounce imbalance flexplate. if you can not find one on a 351 use one from a 302.



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thanks for the follow-up Hoss...I was hopen you would....the crank and motor match(351W), they are 1969..I bought a bare block (69),crank, rods, matching heads (completely rebuilt)and factory alumminum 4-bbl intake for $400...I then bought a complete junk 79 351W for $150 for all the sheetmetal parts and fasteners (they didn't all work on the 69 motor)...hence where the flexplate came from...I'm matching this up to an 85 AOD...the motor is complete now and I'm about to lower this combination in to my car...since I posted this query, I've found from one website (windor-fox) about the difference between the 50 oz and the 28 oz flexplate..they believe that the 28 oz was used up thru 81 for both 302's and 351's and that after that is when they went to 50 ozs (164 tooth)...In the Summit catalog B&M lists the 28 oz used up thru 82 (68-82 28.2 oz for 302 and 351W)......but hey, I'd like to see pictures of your Ford coupe...I had a 50 with a 53 merc motor (wasn't much, but I liked it)...I'd like to get a 51 (always liked the way the chrome wraped around the back), nose and deck it, lowered (down in back) with skirts and painted black...thanks again for the reply...let me know what you think of the conflicting data..



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All 351W's use the same 28 oz. imbalance flexplates. It was only the 302 that changed to the 50 oz. I have an '89 351W in my '69 Bronco and used the original flywheel and balancer with no problems. Ford part numbers aren't a good way to check interchange because they will change the number for the tiniest reason (such as maybe a different supplier) so while the part will interchange perfectly you have no way of knowing if you go by part numbers. Ford may superceed the number but may not, too.



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The data you have is proaably correct. All I know is just what we have learned over the years selling junk auto parts. Just make sure to use the 28 oz. flexplate and every thing should be all right. I just ordered a new computer from Dell, it will be here before chirstmas. It have a scanner. and a digital camara. Don't be surprised if I send YA a present of a pack of pictures. She ain't much to look at. We have not painted her yet. But she runs like a top. I like it when the kids say "Gee mister hows that old junk car run so fast?".



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