I have owned many cars in my life,
probably 20 or so, but I just got my first
Mopar—a 1971 Chrysler Newport, 383.
I wanted to change it to electronic ignition,
which went fine, but now I want to
put a 4-barrel carb on her. I bought a
big-block manifold, an old Offenhauser,
from a local guy I had bought lots of
Chevy parts from. It looks right—but it is
way too wide and doesn’t fit. The seller
swears it is for a big-block Mopar. What
got messed up here?
Mopar has produced 2 basic lines of big-block
engines from 1958 thru 1978. There
are two main families, “B” and “RB”, with
the “R” indicating raised deck, i.e., a taller
and wider engine. Here’s a cheat sheet:
Yes, that’s not a typo, 383s were built in
both configurations, luckily, the RB version
is pretty rare.
Now, here’s a short list of components
that will not interchange between the subfamilies
(B to RB and vice-versa):
• Intake manifold, incl. gasket and end rail
reinforcements, some brackets
• Crankshaft
• Connecting rods
• Distributor
• Pushrods
Everything else, including camshaft,
cylinder heads, exhaust manifolds, oil
pump and pan, timing set, valve gear
(exc. pushrods) interchange.
Welcome to the world of Mopar!