The original thread is over a year old- - - - -it's not likely the OP will respond. Using the 1955/57 265 V8 manifold has been done many times over the years, and it works well. I'm not sure what the original poster ended up doing. A lot of the usual options such as "block hugger" headers, etc. are a very expensive and troublesome fix for a problem that can be resolved by using old stock parts.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!