IF you want to keep it stock looking
IF you don't care about original looks,
there's a ton of stuff to boost the performance
you need to make that, stock or not, apparent & make the right choice
maybe;
get a set of 906 castings 68-70 383-440 HP heads (like it came with org.)
ditch the camshaft you know nothing about
get a good camshaft, for your specific needs & style of driving
get a better ignition box,
go to a Mopar performance chrome box at a min. for the CIE controllers
or an aftermarket controller/Ignition box, like a FOB or Rev-n-ator
get a hotter coil, (coils will cause a bunch of power loss sometimes too)
use low ohm resistance plug wires, like at a min. 500 ohm or less per ft.
lower the better
properly gap your plugs for the type of ignition you have
probably go a step cooler plug too
(depends on your usage & what ignition etc.)
a better manifold like a Edelbrock Performer dual plane intake
(it's closer to a stock low-rise, but alum.)
or better yet* if you don't have any hood clearance issues, you shouldn't
unless you have an N96 Airgrabber hood,
it may have some under-hood clearance issues
*great street manifold Edelbrock
Performer RPM dual plane,
a have a heat shield under the carb,
maybe even block off the heat riser going to the manifold
if it has an electric choke,
disclaimer;
if it has a mech. stove choke
don't block off the heart riser, unless it's only driven in warmer weather
& the choke is disabled
check & see what the fuel pressure is
if the pressure is below 5 psi,
it'll probably never perform all that well
there's a lot of little tricks you can try,
that don't cost all that much
maybe even with what you have now
bump/put a tad of advance timing into it,
a couple degrees advanced
try like in the 15*btdc or try to bump it up farther, until it starts pinging
then back it off a tad/couple degrees
or old school try, with what you have now
set the idle screw at like 2800-3000 rpm,
loosen & turn the distributor slowly 'advanced' it
(you can leave the vac. adv. hooked up)
until you get the highest RPM
you need to have a tach to do it right, you can do it by ear too
(if you got a good feel for it)
& a timing light to know where it is too, for reference if nothing else
after performing that
tighten the dist. back down snug so you can move it with you hand still
but it won't move under acceleration
then turn the idle screw back to normal, shut it off
make sure it will still start normally, if not back off the timing a smidge
then go out & test it
once it's right tighten the dist. back up
& enjoy
all engines like a little different timing
your may like something some other combo doesn't & visa versa
it doesn't cost much if any to try
On the Street Demon,
make sure the needle & seat/float levels are where they should be too
accelerator pump setting too
it could be affecting the performance, if wrong
again like
said above if the fuel pressure is
below 5-psi
you can put a gauge on it inline somewhere fitting out there
that have a 1/8 pipe NPT, to screw a fuel pressure gauge into/inline
or right off the carb fitting
especially WOT (wide open throttle)
it probably won't perform well under hard loads
lots of stuff to try
the heads are the biggest choke point & an orange control box (shitty)
from what I read, what little information we/I have...
engine are just huge air pumps what goes in must be able to come back out
an exhaust blockage restriction or something like that,
may rob power too, feel like a turd especially going uphill
much like a clogged fuel filter does too
could have a restriction in the fuel lines, old fuel lines & old sending unit socks
are notorious for that ****
good luck
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