Thread: Does This Combo Sound Right To Anyone?

Tweet

Displacement: 383 cu. in.
Carburetor: Holley 750 double pumper
Heads: Air Flow Research 190cc Street
Intake: Air Flow Research FloPower RPM
Camshaft: Comp Cams 280° Magnum hydraulic, with 280° of duration, 230° of duration @ 0.050 in. lift, and 0.480 in. lift
Headers: 1 3/4 in.
Distributor: MSD
Timing: 34°
Comp. Ratio: 9.5:1

MAX HP: 471 @ 5500
MAX Torque: 515 @ 4500

Anyone have desktop dyno or good with numbers and can tell me these HP/TQ numbers are close by any means? Really Appreciate It Thanks Alot.

~Chris

look on the left says virtual engine dyno download away..lol

It sounds close but your horsepower numbers might be a little high and your torque numbers should be real close. If you could flow a little more air in your heads youd be about right.

Originally posted by Rx7
MAX HP: 471 @ 5500
MAX Torque: 515 @ 4500

Oh no, that poor little RX7! That thing will scream!

Isnt that bad boy rotary powered not Chevy powered! Just curious either way i agree it will scream.

Your low on compression for aluminum heads and 230 duration.

your low on cam lift. AFR heads max flow at @.600 lift.

When i used H-flat type cams I always used 1.6 rockers to at least get them into the low to mid .500's

I say it looks good, but i personally would get the 195's or a CNC chamber brodix RR 200. Also your compression is fine unless you want every last inch of power out of it, and id call around to different manufactureres besides Comp, theres alot out there besides them.

I consider anything less than 10.5 low static compression with aluminum heads and cams in the 230 degree range. You need to sit down and figure out the DCR compression ratio.

383's are real torque monsters. I originally was worried about installing too big of heads. So instead of installing my 248 cc Brodix -11's race ported with 2.15/1.625. I bought the ported Dart pro1 227cc with 2.08/1.625.

Three years later and 22,000 miles I often wish that I had installed the larger heads. I'm running 11.2 compression on 91 octane pump gas with my solid roller setup.

The higher CFM the headsflow the less cam is required to make the same amount of power. I also now run valve lifts in the .635/.644 range

I also run a calculated 11:1 in my daily driven 73 Nova. Its a 350, RR200 Brodix heads and the works to be short about it. And i could probably actually get away with 87 octane if i kept off it. Ive done 90 before and had not a sign of any detonation even under load when it was 90 some degrees out. I completely know the DCR factor. But if this isnt a car going for every last little hundreth then i say its not a big deal. My DCR is in the mid 7's and my car to say nicely is no pooch. Ill get some numbers for ya this spring/summer. If i had another half point of DCR i doubt it would make the world of difference ya know. What are we talking about there maybe 2% increase? My neighbor runs that same generic cam with an 8:1 truck 350, with old crap smog heads in his wifes camaro and the car is pretty quick, and sounds great, he thinks with tuning and such it would go 13's, so i can only assume that with 9.5:1 it wouldnt be bad. My point is if the motors together then 9.5:1 would be fine. sure 10:1 even 10.5:1 would yeild you some more power but at the sacrifice of running 89 gas and possible detonation in bad circumstances. Its your call.