Buddy of mine is dabbling with and old Plymouth 260 Poly motor. He called me looking for info on procuring a crank and rods. Apparently it has a spun rod bearing. He’s wanting to know if there are other cranks that will interchange. Anyone have any ideas? I gave him 73RR’s contact info.
Depending on how badly the crank is damaged, your better equipped machine shops used to be able to weld up the damaged the journal and regrind the crank. Probably not the easiest engine to get a reconditioned crank and bearing kit for these days, but who knows. I have no idea which way would be more cost effective these days. You might also consider having the connecting rod reconditioned if the damage isn't too bad. Should work fine for a mostly stock street engine. Posting some pictures of the damaged parts will get you some better opinions.
The 260" is the small end of those old dogs. He'd be power and money ahead to find a later, larger displacement 318" poly motor from the late '50s - early '60s. It would cost the same to build but fifty-eight cubic inches is 22% larger; why not go for the extra horsepower? jack vines
I agree with PackardV8. A poly 318 should not be too hard to find, they made lots of them. I had one in my 57 back in the sixties. With an Isky cam, Hedman headers and two four barrel carbs it was pretty quick. Even leaving it stock there would be a big difference going to a 318.
As mentioned, if the journal is too far gone for turning then they can most certainly be welded. As for interchange the 241, 259 and 270 all share the same crank and rods.
To all of you that recomend a 318. Its not the same engine as the 55 poly. The 55 poly is more and less a Dodge poly that come as a pick up engine 54. The engine that become 318 come in 56. And its need to be 61 or older to fit the transmission.
The Jalopy Journal
