i just put 500 miles on my fresh 383 and its not that impressive. this is the kit
http://store.summitracing.com/partde...0&autoview=sku
with this cam
http://store.summitracing.com/partde...K&autoview=sku
and an edelbrock performer eps manifold, edel 650 carb, hooker headers, flowmaster cat delete.

so it seems like it doesnt want to climb much higher than 4 grand, atleast in third gear(which seems like timing)(set at 2 or 3 initial and 33 full)... and sometimes when i apply part throttle, cruising, it sputters for a second(which seems like carb).

I was expecting a lot more power out of this. im draining tho oil tom. and will pun a magnet through it to check for metal dust... maybe the cam wore excessively.

does anybody have any ideas whats going on, what i could change?

 

what heads you have?

thats a fairly mild cam and mild compression with 64cc heads. plus the intake isnt the greatest choice either IMO.

But its probly just needing tuned up alittle. get it running right before passing judgement and then take it to a track

my car felt slow to me at first but it was lean as hell. I rough tuned it and felt better but still slow, but when i raced it it ran 11.6's at 116... i was kinda shocked but at the same time i expected more... it wasnt really tuned yet either so that helps. the next time out i'm knocking on 11.4x's and 119mph. Getting better with tuning.

I'd say work to get it running right first

 

im running ported and polished 416's with a valve job. they are 58 cc chambers so compression would be right up there, lk mid 10's. i know the cam is pretty mild but i was hoping to make ATLEAST 300 to the wheels. do you think thats reasonable?

what could i do to tune it up? what did you do?

 

i think your 300rwhp is abit high for ported 416s... your cam is mild too... ud have to making more than 350hp at the crank to get 300rwhp.

your timing is def off... 2-3 intial is too low. i would start out with 8-10 and work your way up or down. stock TPIs were set at 0 sumtimes and bumping inital to 6-8-10 would make good power. i would try 8 inital. wat distributer u running? if its a vacume advance make sure u have it disconnected while setting inital. should be like 6-10 inital, vacume connected and at 1500rpms in the mid 20's timing, then at 2500 rpm vacume connected should be no more than 36 total.

could be the carb too, tuning will help alot. u need to find the right jets for your setup. are the heads rebuilt? past 4 grand it could be getting alil valve float with the old or wrong springs.

 

yeah basically play with the tune and the carb. get the fueling down. if those heads are ported pretty good and have a little bit of flow to them, there is no reason why you cant hit 300whp with a 383.

with those heads at 58cc, your compression is 10.93 to 1 assuming standard deck to head clearance of .040". thats way high for iron heads. you'll have to keep timing down and run 93 octane gas if your not doing so already. Hell, maybe even throw a few gallons of 105+ octane race gas in the mix

you really need aluminum if your gonna go that high on compression. Thats pretty high with iron heads. taht cam isnt helping either, thats gonna raise the dynamic compression. you will want a cam with more overlap and duration to keep things abit more happy.

 

double post.

 

here is my $.02 ...

if you are going to build an engine for high performance, dont cheap out on any aspect of it, much less the heads.

416's probably (not to say they couldnt if worked over well) wouldnt flow high enough for a radical 350, much less a 383.

i dont know what you paid to have the heads worked over, but i would have went with a set of aftermarket heads. AFR or Dart which probably wouldnt be too much more.

also: if your goal was only 300 RWHP, you could have easily done that out of a 350.

as far as the cam goes, the one you have is really small. i dont know the specs on the heads as far as possible lift and the springs go, but i think a bigger cam would greatly help the lack of power situation.

what i would do now, would be to do some serious carb tuning and dial in the timing.

 

i did the porting myself, and paid 200 i think it was for the 3 angle valve job and assembly. the springs are the ones that came in the cam kit.

ok so i will get a hold of a timing gun and up the initial a bit. as for the carb. what is there to do? change out the jets and what else?

i am also going to be changing out the thermostat b/c its running right around 150 right now. i was going to go with a 180. idk if that could have affected anything.

 

as far as the carb goes, i hate edelbrock. they are a pain to work with and tune, and if you were to ask pretty much any experianced mechanic, the would say holley or demon.

i had an edelbrock on my 1987 LG4 and it was a pain.

i have a Holley on my 1985 IROC and i love it. straight forward to tune, TONS of parts available (most in stock at Advance), lots of product support, extremely knowledgable techs on the phone, and gets the best results with less messing around.

Demon, i have never had one, but they also have a great reputation, but they tend to be a little more expensive and a bit more complex.

as far as tuning your existing edelbrock, check the Carb forum on here, or google for tuning writeups.
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another thought... gears would make it feel faster if they are stock.

 

well i have a holley 750 dp available to me, should i put that on and see if there is any difference? how much worse gas mileage would i get?

 

gas milage is almost all in the tuning when it comes to the carb. if you get it tuned to the "just right" which definitely takes some trial and error, your gas milage wouldnt be any worse than it would with an edelbrock carb (which judging by your posts isnt tuned).

i would say go for it.

 

I assume you're using a vacuum/centrifugal advance distributor. 36 degrees total centrifugal (mechanical) is more typical of SBC's. 33 shouldn't be causing severe problems, though.

What damper are you using? You might not be getting accurate ignition timing data.

416's have the same port sizes as 083 L98 heads. If still the stock 1.84" intake valves, that will hold you back a bit. But, 4000 RPMs sounds much too low for that to be the issue.

Time to verify the basics - ignition timing, carb tuning. Are you sure the cam timing set was installed properly?

 

friend has a demon on his 88 mustang LX on a 302 bored .030 over.... pulled it outa the box put it on... didnt even have to tune it... he talks alot of cr@p but i'll show him. the demon carbs are nice, much more complicated than a holley tho... they are more compact and to me look nicer. still a holley looks good

u need to tune it. def check your balancer. and set the tune... its not just as easy as changing the jets... u need to figure out wat the engine is doing.. running lean or rich.

they say u can put great heads on a cr@ppy cam and still make good power, but put cr@ppy heads on a great cam and u aint got SHlT!

better heads on your setup even with that mild cam should give u enough to get your 300rwhp.

 

ya, its the hei with vacuum and mechanical advance. its a stock balancer, 2 o clock. a professional engine builder assembled it so im expecting that its in right. i put the same cam in my previous 350 and degreed it and needed no spacers.

it never seemed to cut out like it was loosing compression but just wasnt climbing fast at all.

ok well i am smelling gas a lot, and it seems to have trouble starting like its flooding. to change this do you just adjust the 2 screws in the front? which way makes it run lean/rich?