Ok, this is going to be a bit of a weird one. A mate of mine just put a EB V8 into his XY. We got it running all fine, but it has nasty vibration that gets worse when revving. It doesn’t make any difference if the car is driving or just sitting in park.
We haven’t hocked up the O2 sensors yet, but I doubt this could cause any trouble. We are running a C4 behind it instead of the BRT 4 speed. What we believe the problem might be, is the BTR flex plate had a weight welded to it off centre, but the C4 flex plate didn’t. Could this possibly be causing the vibration or might there be another problem. Did they change the cranks significantly between the 1971 Windsor’s and the 92 ones…

Any help would be great..

Cheers
Tim

What about the harmonic balancer? Is it tight or loose?

Yes the older windsors ran a 28oz balance while the late model EFI's run 50oz. B&M do a special order C4 flexplate with 50oz balance.

Great, thanks for the quick replys.