I'm a chevy guy, but now own a 69 dodge dart western special with a 225.

But im also rebuilding a friends 273 out of his 1964 barracuda. I just have a question about the timing chain cover, i bought a new one from summit because his old one was cracked. The new came in looking exactly the same BUT, there is one extra hole on the right hand side that does not make sense. I will admit, the one i bought says it was for newer engines, but i couldnt find one for a 64. Does anyone know what im talking about?

 

i dont have a 1964-1965 273 manual. but i do have a 1967 273 dart manual. the pics that show the front of the engine. but that face shows only the bolt holes, in the block. if the your hole is smaller than the bolt holes my guess is its for a dowel pin. some years of the small block do not have a dowel pin on the timing cover. the years that dont have the dowel pin, you just let the seal center the cover, and bolt it on. i used a dial indicator to center the cover and drill it for a pin. but you have to be VERY careful to not drill to deep else you hit a water jacket. i would not do it again. most seals can be off as much as + - .010"