overfiring

[J MICHAEL SHAW II <103253.3336@domain.elided>]

Okay, I know you guys are sick of hearing about this problem, but I have a
new question.  I thought it was going to be a few weeks before I had any
new input, but I just found out, from the guys that fixed a leak in my
exhaust manifold, that I have some leak in my intake manifold.  Could this
cause misfiring and "bucking" once the engine is warmed up and travelling
under load.  My thinking is, once the engine is good and warm, and some
minor level of "expansion" takes place from the heat, this leak could be
increased by the increased vacuum created under load, causing a very faulty
air to fuel ratio going into the cylinders.  Does this make any sense to
anyone, or am I reaching here?  Any input would be greatly appreciated.
Thanks!
J. Michael Shaw, II
103253.3336@domain.elided
1973 Scout II, 345 (Giving me headaches)
1968 Travelall, 345 (Needing new crankshaft)
1966 Dodge Monaco (Thank God it works!)