my77project

this goes out to my77stang in particular, but anyone else as well who knows the answer. I know that around 80 they switched from a 28 oz flex plate to a 50 oz one. my question is, can I take a late 80's motor w/ 50 oz flex plate and mate it to my 77 c4 transmission? I know the flex plate effects the ballance of the engine, but I don't know what else it effects as far as the interface with the tranny etc. help would be much appreciated here as I'm trying to figure out what option I should take w/ my engine.

my77stang

you need the harmonic balance and the flexplate to both be 50 oz. the problem is a regular 302 flexplate will not fit in the Mustang II bellhousing. So, the answer is to take your 28 oz Mustang II flywheel and have it rebalanced for a 50 oz application. I used to have one, but it got sold on ebay a few years ago.

btw, you can't just use the old 28oz harmonic balance and 28 oz flexplate on the later motor. that = essploded motor

(can you tell i've done this before?)

my77project

just curious, but why does that make an exploded motor?

my77stang

because it does


but seriously, the rotating assembly needs a 28 or 50 oz balancer/flexplate to offset the imblance of the crank/pistons/rods so you cant just mix and match [8D]

mjr46

the imbalance if not correct will make cottage cheese out of the mains..it'll cause way to much harmonics...you can buy a 50 oz flexplate for a c-4 they are cheap!!! cost under 150.00 or even less I believe

my77stang

the problem is the II's have a smaller flexplate than used on any other 302. its Mustang II 302 specific for 1975-1978.

my77project

so can most machine shops do the reballance?

my77stang

any machine shop that has a balancer.