i am sure you guys have a lot of people asking about power questions so here is mine. I am in the final stages of my 383 sbc and the machinest said the combo should be in the 500 hp range is he crazy or not?.
here is my combo:

78 350 block .030 over
400 steel crank 5.7 h beam rods w/wave lock rod bolts
standard deck with 11.1 weisco forged pistons total comp should be 10.7-1
dart pro 1 aluminum heads with 205/160 stainless valves and 215 intake runners 1/6 erson roller rockers double bar stud girdles
pp single plane intake port matched with 1 inch spacer holly 700 dp
comp cams cl12-771-8 mechanical roller 242-248@50 610-616 lift w/1.6 rockers 110 lobe sep 106 center it also has a rev kit
milodon 7qt oil pan, crank scrape, windage tray, oil pan rear baffle, melling high volume oil pump
msd distributer and msd digital 6 with taylor wires

its a 85 TA gutted with an 8 point cage, subframe connectors and kirkey aluminum seats. I am going to also run some sort of plate n20 kit 150-200 shot. any guess on times all permitting that it has traction?

 

i think that sounds pretty legit... 700 cfm carb tho? i would think a 750 would be needed at least

 

If assembled and tuned correctly it should make 500hp no problem.

 

i have been told that 90% of people over carb there engines. i have a holly tuning guide that gives you an equaison to find the correct cfm per application: cfm calculation 383/2 - 191.50 x 7200 = 1378800/1728 = 797x.085 eff = 678.229 cfm estimate. i guess that really does not explain anything but if you have speed pro series how to build and power tune a holly you can find the calculation on page 25.the first bold # is the ci of the motor and the second bold is the estimated effeciency of you motor.

 

I dont know if that is accurate. I ran it through 2 diffrent calculators and got 822 in one and 936 in the other.

 

which calculators are you using???

 

thats similar to my old set up but i had 1 step bigger cam .630 lift , and the dart 230 heads . with my 700 on it ran 12.3 and with my 950 it ran 11.9. (corrected alt. was 4000 ') the 700 was fine on the street , but after that pick up at the track i never put it on again. and if your on getting 85 % eff. your doin something wrong.

 

You should be able to run atleast a mid or low 11 with that combo assuming you have it tuned well and get traction. So yes that should make 500+HP. Like the others suggested I would think about a 750DP carb at minimum, 850DP might be even better. I would also suggest porting those heads. They flow decent out of the box but respond very well to porting, you would see some good power gains with porting. Those are the same heads I'm using, after porting they now flow 303cfm/225cfm@.600lift.

 

I am a roughly 5000 feet so if i can make mid to low 12s on motor the squeeze should put me deep into the 11s.

 

my friend has a mild 350 in his truck and he used a 750 carb and it ran very well.. 83 shortbed chevy and it went 13.6s at 98mph with just vortec headed, lt1 cammed small block 350. he switched to a 750 double pumper and it picked up well on the street.. hasnt ran it at the track yet tho.

i'd definately go 750 for that 383. its all in the tune tho so as long as u get the a/f right it should work either way