I think my 225 is toast
A lot has happened over the past two weeks. Last Saturday, acquired a motor & trans from member
ms2420
Thanks, man.
Pulled the old motor
Changed out for this low-mileage '71:
changed the trans fluid & filter
some crud located
and cleaned
Motor started right up after a pre-oiling spin, immediately demonstrated a pretty good exhaust leak at #1 in the manifold. There followed a lesson (a saga, really) in Slant 6 manifold gasket replacement, with the agony of snapped bolts & studs & the ecstasy of drill bits and taps. And magic hidden nuts, and screwdrivers as guides, and three types of washers...good god.
After replacing the gasket and finding that my old cheapie torque wrench cannot reliably pull 10-ft/lbs, I got it all together...
only to find a massive exhaust leak at #1.
After pulling the thermostat housing, the problem was located: a gap of at least .025" in the bottom half of the #1 port. I loosened the manifold & squirted in a ton of copper RTV, but I doubt it'll work, or hold.
Looks like I'll have to prep* the exhaust manifold from the old motor. Meanwhile, the RTV cures, and the bypass hose was replaced, since after having hot exhaust blow on it for an indeterminate period, it was like a rubber band.
Still and all, it's good to be working on MoPar and a relatively easy car again.
*
drill out the snapped bolts
To follow: photos of the bottom end.