When I switched out my 318 for the 360 a few years back... I think I used the B&M flex plate, and the 318 TC... I'm getting some resonating, harmonic vibrations when driving, sometimes they even slowly pulse..reeeeeow... reeeeow... and have replaced a few things along the way, but it's still there.

this weekend I'm pulling the tail shaft and having a new brass bushing installed, and both U-joints are new, the drive shaft is balanced and straightened, the rear axle has been upgraded, and I have a rear trans mount ordered.

The only thing I have in question is my torque converter... if I wanted to order another, say with a different stall or just a new one that doesn't have a bazillion miles on it, can I order one for the 360 and still use the B&M flex plate? Will it bolt up?

Any other places I can check that would cause vibration?

Is the vibration in park/neutral and drive or just in drive.

Check you bellhousing bolts. Mine were loose and caused a vibration in P/N and D when the engine revered over 1500 rpm.

Jason

I will put a wrench on those... I only notice it when driving above 50 or so, and more so when going down a long hill off the gas... I put the car in neutral going down a mountain for a second, and it wasn't as bad but still vibrating. It idles and revs in park okay. It's a motion-related vibration.

To answer your last question - order a torque converter that is neutrally balanced and use your B&M plate or if you order one for a 360 and it has the external weights on it you cannot use your B&M plate unless you cut the weights off the converter first.
You cannot use both the weighted 360 converter and the B&M plate. One or the other but not both.

So if I had a 360 converter with the weights, I would need a 360 flex plate?

you need a combo of either...

a weighted converter and neutral flexplate

or

a weighted flexplate and neutral converter...

NOT Both...

I had a vibration also that was there in nuetral and driving. And after going thru all possibilities, balancing shaft changing ujoints, and going thru convertor swaps and trying the different convertor and plate combinations as we thought it was the convertor, it ended up being the motor mounts. Changed the motor mounts and vibration was gone. And after I changed them, we had a hard time finding one side, I found a few pairs of NOS pieces.
Anyways, check your motor mounts, even if you changed yours recently as the aftermarket jobber store ones tend not to last (if you can find them at all now at the jobber stores).

They were new as of the engine swap, but I lost a u-joint on the rear and it ended up splaying the rear yoke apart and I chewed up a few more before I could get the axle fixed. I'm guessing it rattled something else?

I can't mess with it until Saturday, but I want to look at everything. I have to take it to Charlotte next weekend.

That converter from the 318 should be fine as long as you used the B&M flex plate and no weights on the converter.

if you don't get the vibration standing still at the RPM you're feeling it down the road, I don't think it's the converter....I'd check your motor mounts and tranny mounts. the fact it's better in neutral than drive leads me to believe it is an issue with your pinion angle

Ooooh, good call. I will check that also. I did swap out rear end with another one from a 73, but I do have the rear raised up..

check u-joints for vibs as well as pinion angle

make sure its the correct length and the yoke is far enuff in the tail saft to be supported

the will vib at speed if not slid in far enuf

also a good idea to have it balanced at a drive shaft shop

check to make sure no wieghts have been knocked off

watching this thread, having some vibration issues also.

Vibration checklist
Go through and consider all indications

Idle in neutral
Idle in drive
under accel
Under decel
RPM related
Speed related
curve related
single gear related
Steering wheel, seat of the pants, rear seat passenger?
Time from start
Distance

You say you think you used the B&M flexplate. If so, you need to make sure you have the right one. The 318 is internally balanced and the 360 is externally balanced. The 318 converter has no balance weight(neutral), the 360 converter is weighted. B&M has a flexplate that allows a neutral balanced converter to be used on a 360. Has a scooped out section to balance it. http://www.summitracing.com/parts/BMM-10239/

I am sure we used the 318 torque converter and the B&M plate.

Where is the balance, uh... balanced, exactly? How is one internally balanced?