I would suggest using a dual plane intake manifold for the street.  I
was using the single plane Edelbrock Torker 351 and I found it was not
very friendly for daily driving. I have since swapped the Torker for the
dual plane Edlebrock Performer and am pleased with the performance on
the street.

Yet another $.02 worth from a proud owner of a 1970 Mach 1 351C @
http://community.webshots.com/album/18644819fHAehGJAjt

i like the eidlebrock

hurc ast

Why are you replacing that intake?

My completely gone through (fairly radical cam, don't have the cam specs
on hand) '71 351CJ Cleveland still runs a factory (well mine is one of
the ultra rare aluminum versions, same runner design though) dual plane
intake manifold, with a Holly 850 double pumper. I also swapped the open
chamber 4-V CJ heads out for a set of closed chamber (quench) heads

If you do some research I think you will find that the factory Cleveland
4-V cast iron dual plane intake manifold will offer such comparable
performance to any of the available after market dual plane intake
manifolds from stock to fairly radical camshafts with stock 4-V head
setups as to make replacing it a near ZERO gain proposition.

I would suggest you apply that intake manifold money toward a new
electronic ignition.  The noticeable benefit will be huge.

Good Luck