461 "X" Heads Revisited,

[Joe C.]

The following is a copy of a post from another website:

..................my pair #461X measure 173 to 174 CC's
i pulled those Heads off the Engine myself,
the Chevelle was almost within a Baseball throw from my Shop
sitting in a field by this Guy's House.
This old man purchased the Chevelle brand new in 1965,
a few years later he died...many years later his son and i removed those Heads off the 327 engine.

i have the "other" 461X 170-172 CC version also in my Shop,
that NHRA went off of....they are different than these rarer 461X 173-174 CC heads

i also have the other 461X ( 3rd version ) that will measure around 168 CC
they are visibly different and measure different in bowl depth and pushrod width

so there are at minimum 3 versions of 461 "X" Heads i've seen
they progressively measure different
in Bowl depth, Short Turn height, and pushrod width,
and have different outside casting characteristic peculiarities .

then there's a plain 461, maybe 2 versions of these
those will probably be around 165 CC's

then theres a 461/462 version
these will be around 162..these are the smallest of the 461 castings ! _______ ___________

Brings to mind a discussion we had here a few months ago regarding visible casting differences among 461 heads, both "X" and "plain" versions. As expected, there is a whole lot more to it than meets the eye, and these experts seem to have gotten the performance parameters pretty well "nailed".

[Clem Z.]

Re: 461 "X" Heads Revisited,

the port CCs depend on the type of intake valve used and if any valve jobs have been done and how they were done. the NHRA allows the max of 172 cc intake port on 461X heads

[Mike M.]

Re: 461 "X" Heads Revisited,

the original 461X heads on my 61 315 HP vette had a volume of 164cc and they'd never been off the engine prior to me rebuilding it. the heads were cast date jan 3, 1961. mike