Technical Id'ing a nailhead help.

Hey guys. I have a 60 electra im parting out and i need help id'ing the nailhead in it. Thanks

 

401?

 

If the original engine, it is either a 364 or a 401. Look at the stamped numbers on the block just in front of the valley pan on the driver's side and report back. 3G= 364, 4G= 401
Another way to tell is the intake width- what does that measure? It appears to be a 364.

 

If it has a 4 barrel on a 364 the intake casting will end in 333. If so that manifold is rare and worth about $600

 

^^^ and to think I scored one for 25 bucks...

 

Thank you

 

Thank you