are a 318 and 340 crank the same

[troy.70R/T]

Just wondering if a 66 318 polyhead engine has the same crank as a 340?

[Cooter]

Just wondering if a 66 318 polyhead engine has the same crank as a 340?

Same stroke and some 340s were cast cranks. Yes, I have heard of the later stroker crank being retrod to the poly for a stroker poly.
As plentiful as later style LA motors are, I would forget using anything from the poly engine.

[A383Wing]

the torque converter "hole" in the back of the crank may be smaller in the poly crank....I know they are for the 273 auto cranks...they will fit in the engine, but may not work correctly for other engines

don't ask how I know this

[troy.70R/T]

Thanks for the help guys. I guess I will just sell it as  66 polyhead 318 crank.  anyonee need one??

[Cooter]

Polyhead engines....
Kinda like the early 245-331 hemi engines. Way to big, heavy, no hp, and cost to much to build.
Look different, but in reallity, they are boat anchors.

[troy.70R/T]

Great now I have a reason to buy a boat.