My son and I have been building
his ’85 Dodge Ram W150
with a 318 and 727 TF. The truck
has 27,000 original miles on it, as
it was an old Air Force truck. He
ported the heads and put a larger
cam in it, new lifters, roller rockers,
headers, Edlebrock intake and
carb. With the larger cam we had
to install a B&M 2400 Holeshot
converter. All worked good for
about 2 days, then the truck
developed a droning vibration in
park and neutral or when driving.
I know that 318s are internally balanced.
The stock torque converter
has no weights on it and the B&M
TC is neutral balanced so it should
work with the stock flexplate. So
with all that said, what could be
causing the problem?
Since it was fine initially, my
best guess: Loose cap screws,
either converter drive plate to
crank or drive plate to converter.
The rear engine mount (“tranny
mount”) could also be loose or
broken.