318 poly heads?

1wild&crazyguy said

Yep, no worky on the head swap.

The crank/rods yes, but the consider the year for some had flat crank flanges with no register.

Other than valve layout, between the 2, the Poly castings weigh more, even the rotating assembly weighs more, 2 lifter angles...chrysler came up with a redesign based on the cid/Bore&Stroke but with lots of weight shaved of, It's called the Light Assembly or LA 318
IMO The poly valve layout is nice and are where the P series Race heads sorta came from.
They just weigh a ton for how small the cid is, stroking one would kinda make up for this, but then there is only about one intake available , maybe 2 if you cn find the dual 4 factory iron, otherwise it's the weiand dual plane.

Click to expand...

I built a three of them, back in the day. I had a 58 Plymouth, JSA forumla 5, AHRA, running a 2 barrel.
My first car, a 57 Fury had one, then I did a frame off on a 57 Fury in the mid 80s.

I don't think I could tell the short blocks apart, from an LA motor, except for the valve reliefs on the pistons. Both use 10 head bolts, rear distributor etc.

Even when those motors were in production, there were almost no speed parts. That was probably difficult to justify for the manufacturers because the Dodge Poly was a little different.

I always thought it was a shame, because the motors really did run good, and had a lot of high rpm characteristics of the Hemi. They were all solid lifter
motors, and I still think that the BBC canted valve design was stolen from the Poly.