75cc Combustion Chamber Edelbrock RPM Heads (about 40 hp over 906 stock)
are probably the best head/bang for the buck, for the $$$, for street/strip use
make about 30-40 HP more out of the box, than the Stealth Heads
(like 65#+ weight off the front end too)
have better heart shape combustion chambers, that have 14mm x 3/4" angle plugs,
out of the box none ported, 210cc/290+cfm flow at 0.600" gvl 'without any porting'
with porting can easily be done to 330cfm @ 0.600" gvl with a good professional porter
the Stealth head are like 212cc/259cfm flow (about 20hp over stock)
about $400-ish less than the Edelbrocks (40hp less too),
have straight plugs & look more like a stock head, & make less power
the best head about $600 more than the Edelebrocks ($2,000-ish a pair),
they are CNC ported, well worth the extra $600, for porting alone
would be the Trick Flow 240's std port
no such thing as too big, (to an extent, 'too big' that BS old wives tales)
383 likes to rev, they will love the bigger std ports, more flow
even the TF 270cc's flow like 330cfm, have a MW raised ports (75-78cc)
(you will have to grind a small 1/4 moon shape for the intake valve
on the cylinder tops, so it will no be shrouded & effect flow, outside of that, no too big deal)
they don't show much if any loss in bottom-end toque,
& another 20-40 HP over the TF 240's
technecally means, "they are still a too small intake port, for max power"
& it means, they can still be even bigger
(TF's have minimally bigger intake valves than the EDDYs, but smaller exhaust valves
you could run a smaller diameter tube on the headers, you need at a min. inside tube diam.
the size of the exhaust valves)
(BBC canted valve alum. heads, have a rect. port that flows 330cfm on a 396 425hp
no shrouding issues with the BBC, canted valves)
(cylinder wall valve clearance can come into play on a BBM wedge,
with the smaller std 4.250" 383 bore & bigger intake valves)
with the correct induction/intake carb etc., right cam & converter, gears etc.
even on a 383, it will be a beast
motor doesn't care it's an air pump, more air the better
what goes in must flow out, freely
don't buy the BS too big of ports, until you get into the 300cc+ range (400+ cfm)
for a street build, even then it depends on the combo
flow is flow, don't impeed flow, it's a HP killer
MoPar knew that even when they made the MW heads,
they were still way too small, even on the 413, but way better than the std wedge ports
watch the MotorTrend 'Engine Masters' (3) episode/s on Wedge Head compairison
there's several of them, the 3rd itteration was comparing the 240 to the 270
it was still too small to effect the bottom end torque
on the exact same mild 440, they tested the OE 906 iron, vs Stealth, vs the Eddy RPMs,
zero deck flatops, work great, w/valve reliefs,
with the smaller chambers can get 11:1+ compression, with a valve reliefed flattop piston
depending on the headgasket, you can get form 0.018" compressed shims,
to 0.050" Cometic/ML gaskets, the thicker will kill some compression, more quench too
I ran their 0.025" x 4.35" Cometic gaskets (every lil' bit helps)
a std. Fel-Pro Permatorque/Blues is 0.039" compressed
