I assume yours is a single 4 bbl {?}
I have the purple/violet & silver ones from a kit I got
from Mancini Racing they seem to do pretty well
But they are 6bbl specific
& I have a taller Throttle cable holder/kick down linkage
& a taller spring holder too, from Mancini Racing also...
better alignment for the cable etc.
especially if you have a taller intake or spacer & a taller intake
just spit-balling here, might not be applicable at all
you sure your throttle cable isn't the problem ?
or the hold down has pinched the cable or housing ?
not the springs strength ? possibly {?}
these old org. cables, 40-50 y/o cables have a tendency to be stiffer
harder to pull on, more resistance
a new cable may be the answer too {?}
is the peddle mechanism hanging up inside ?
maybe some lube will help too, it did on my org. cable & peddle
are you sure the gasket under the carb isn't hanging the blades up ?
or something else causing it to be too stiff {?}
seen some strange or weird **** over the years
It'd seem it doesn't really need to be all that strong,
if everything is aligned/working properly & nothing hanging up...
again none of it may apply, just spit-balling
they make them for a B-383 or RB-440 auto or manual
the taller spring bracket seemed to pull back better than
the org. spring bracket wanted to pull down, more than back
if that makes any sense
I always do dual springs too, old habits die hard
of course that's if it's not a 100% OE restoration,
than ignore most all the above
, the lube or sticking may still apply
