Diputado

Hey folks, I mentioned this in another post, but maybe everybody thinks I'm an idiot, as nobody answered or offered advice. So here goes again. Here's my situation...I have a moderately-built 289 in a '65 coupe and am in the process of rebuilding the Toploader 4-speed and putting in a new clutch and pressure plate. To my surprise, when we dropped the transmission, we found it was running a 11.5"pressure plate and a 11-inch clutch. I had already bought a McLeod 10.5" clutch and pressure plate to put in. My concern is the issue of balance if we go to a different size/weight pressure plate with different attachment locations on the flywheel. To complicate matters...the engine has a 50-oz imbalance damper off a 5.0 HO and a 28-oz imbalance 164-tooth flywheel off a '69-70 Boss 302. Apparently, the PO (who built the engine about 7 years ago) did some kind of weird dynamic balancing to make this work, as the engine runs smooth with no vibration.

So...will I have balance problems with the different pressure plate/clutch sizes?

67mustang302

Clutch won't matter.

I wouldn't trust a balance with the incorrect balancer/flywheel though. It can work, if the flywheel was rebalanced to the 50oz style (can be done reasonably easily). Chances are that's what was done. If that wasn't done, then don't be surprised if the crank breaks in the future.

Diputado

Ok..good to know the different clutch/pressure plate won't alter the current balance. That's what the guy rebuilding my Toploader said, too...but just wanted additional "second opinions". The flywheel will be resurfaced today, and in a worse-case scenario that I have to replace it....how easy would it be to balance a new flywheel to match what I've got without actually tearing down the engine and re-balancing the crank/flywheel combo? Like I said...the engine runs smooth as is...so the PO must've successfully balanced those mismatched parts.

67mustang302

Assuming the flywheel was rebalanced for the balancer being used, then get the appropriate 50oz style flywheel. If they did something weird, then you'd have to get your current flywheel checked and have another flywheel balanced to match it.

Just because the engine doesn't vibrate, doesn't mean you don't have balance issues. It's hard to know what people did when they deviate from the norm, unless they let you know exactly what they did.

Diputado

Understood. All I'm hoping is for the engine to last a year or 2 more until I can afford to drop in a decent crate engine (331 or 347). I don't race it, so maybe it'll hold up....it has so far. Thanks for your comments.