I'd guess, it's just that a guess, probably only nominal differences, "maybe" 10-15 hp differences,
A bigger/better carb change & manifold change, could be considerably different thou,
really depends on what carb, how much CFM {how it's actually tuned} & what changes have been done
& if you really needs more CFM or if your already at the optimum tuning & carb size etc.,
IMHFO it needs to be done on similar days & in similar track conditions/weather etc.,
to get areal world comparison on the track, with at-least 3 runs of each at optimum tuning,
back, to back, to back...
I don't really know anything about the MP337 single Plane intake manifolds, never used one...
Maybe some better MPH on midrange/top end, vs's the dual plane Street Dominator intake,
I'd guess probably little to no differences in 60ft times, that's been my experiences,
form swaping from dual plane to a single plane intake manifolds,
BUT
I've almost always used some kind of heat shield &/or 1"-2" Carb Spacer open or 4 port tapered too thou,
which will change the characteristics of a dual plane manifold too, so there will be a little different effects...
Like you said you don't know unless you try... different engine combos like different things
There's a couple of really good articles in Hot Rod Part 1 & Part 2 Mopar Intake Comparisons, back around 2008ish IIRC on a bunch of different intake comparisons, what does what & where it helps etc., it's on a 383 with a mid size cam & hopped up some, but still good relative information...
There's another one from the Engine Master Challenges
There's also a couple of good "old" (2006) write up & comparison articles in Mopar Muscle Mag. too
"Max Wedge On A Bench" using INDY EZ Heads 505ci BB & a plethora of intake manifolds
http://www.moparmusclemagazine.com/techarticles/mopp_0701_mopar_intake_manifold/
there're a few others too, some are older info, but still good information/cause & effect of different type of Mopar induction/intake systems...
Google Search "Mopar Intake Manifold Comparison"
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I wish member
IQ52/Jim would chime in more... he could be some great help,
he ports heads & builds engines Professionally {very well I may add}, he's tried a bunch of different stuff in the
he has done a bunch of dyno tests on a bunch of different heads & intake combos...
He's built some big HP Mopar BB wedge engines for the Engine Masters Challenges too,
under some stringent rules & budget constraints...
