383 suggestions-dyno
Thread Starter
Cruising
Joined: Aug 2014
Posts: 14
Likes: 0
383 suggestions-dyno
Just had my 383 dyno completed, looking for your thoughts, 78 vette with 383, 230/230 cam 110 lobe. .480 lift, flat tappet cam, average aluminum heads, team g single plane, holley 750dp carb, pertronix flame thrower electronic ignition, 1 5/8" headman headers with 2.5 inch stainless steel true dual exhaust, turbo 350 with b@m 10" 3000 stall, shift kit and b@m transmission cooler with 3.55 gears, dyno was 375 rwhp and 370 torque, rwhp seems ok but torque numbers seem low, is the high stall robbing torque number, like to get over 400rwhp thinking afr 195cc eliminators and higher lifters will make cam seem bigger and flow better allowing 400 rwhp, what's would you do, thanks
Melting Slicks
Joined: Oct 2011
Posts: 2,748
Likes: 90
From: Sacramento California
C2 of Year Finalist (performance mods) 2019
2018 C2 of Year Finalist
Why didnt you put a roller cam in it? What compression are you running?
Headers are small for a 383....The auto will sap a bunch of power. What rpm was the peak number? Thats about 450tq at the crank which is pretty good for your mild build.
Headers are small for a 383....The auto will sap a bunch of power. What rpm was the peak number? Thats about 450tq at the crank which is pretty good for your mild build.
Safety Car
Joined: Oct 2004
Posts: 3,926
Likes: 739
From: Youngstown Ohio
My former 383 had similar rwhp (373 hp), but over 400 rwtq, and I also have an auto trans 3000 stall. As DucatiDon asks, need to know peak rpm number.(Current heads?). That being said, 375 is a healthy horsepower number for such a mild cam.
On a chassis dyno it is very difficult to get a valid torque read with an auto trans. It takes a bit of driving "technique". The TQ converter multiplies torque like crazy when it "flashes", and the trans will downshift when you floor the pedal from a slow start. Then TQ numbers go haywire. I have found (coached by the dyno operator) that you must slowly drive to 3500 rpm, allowing the car to achieve high gear, then slowly (you have to feel for it) achieve full throttle without allowing the trans to downshift, then continue to your desired highest rpm. Even then, you will still see your TQ peak when the converter flashes, since you have a 3k converter.....and it's usually quite high if you have an efficient converter.
On a chassis dyno it is very difficult to get a valid torque read with an auto trans. It takes a bit of driving "technique". The TQ converter multiplies torque like crazy when it "flashes", and the trans will downshift when you floor the pedal from a slow start. Then TQ numbers go haywire. I have found (coached by the dyno operator) that you must slowly drive to 3500 rpm, allowing the car to achieve high gear, then slowly (you have to feel for it) achieve full throttle without allowing the trans to downshift, then continue to your desired highest rpm. Even then, you will still see your TQ peak when the converter flashes, since you have a 3k converter.....and it's usually quite high if you have an efficient converter.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Thats a decent # for what you got if you ask me esp with a flat tappet
Sure the AFRs will make a nice jump in power over most outof the box heads. tpi421Vette in the C4 tech section is a good go to guy for them.
Sure the AFRs will make a nice jump in power over most outof the box heads. tpi421Vette in the C4 tech section is a good go to guy for them.
Thread Starter
Cruising
Joined: Aug 2014
Posts: 14
Likes: 0
Max rpm is 5500 while I break in motor, electronic ignition shuts down at 5500 at break in, also timing is only at 34 degrees during break in, compression is at 10.4 to 1, just looking for a little more, should be satisfied it's a fast car but just want a little more, should I do different cam like a comp cam 294s and average heads or great heads like AFR and no cam change, or nitrous 100 shot, feel like nitrous is cheating, is 375 rwhp respectable
Last edited by Floatplanepilotguy; Aug 9, 2014 at 10:26 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Instructor
Joined: Jan 2011
Posts: 146
Likes: 2
From: Hillsborough NC
FPG - I think you have pretty good numbers, especially considering you stopped at 5500. 1&5/8 headers are good for TQ and the 230 cam; may want to go bigger if you switch to a bigger cam to get more HP.
Before getting new parts, do you know what your quench is and have you port-matched your heads/intake?
Before getting new parts, do you know what your quench is and have you port-matched your heads/intake?
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
That translates to about 500 RWHP. Very optimistic Dyno.
AFR 195 heads with 8019 springs and this cam and 1.6 rockers http://www.compcams.com/Company/CC/c...?csid=152&sb=2
Will get you a bunch more power across the board with identical drive characteristics and powerband.
AFR 195 heads with 8019 springs and this cam and 1.6 rockers http://www.compcams.com/Company/CC/c...?csid=152&sb=2
Will get you a bunch more power across the board with identical drive characteristics and powerband.
Le Mans Master
Joined: May 2007
Posts: 5,025
Likes: 1,120
From: North tonawanda NY
if you want more torque why not go to a dual plane intake? it should certainly deliver more torque on the street. IMHO single planes are great for WOT but second to a high rise dual plane in every other scenerio.... Especially in a heavy car. A dual plane will make it "feel" faster on the street but a single plane will show you quicker numbers on the strip...take your pick.
Last edited by augiedoggy; Aug 6, 2014 at 07:48 AM.
Thread Starter
Cruising
Joined: Aug 2014
Posts: 14
Likes: 0
I would say more like 450hp at crank, minus 20 percent loss equals 375 rwhp, I have spent a lot of $ on this car and i have couple more thousand to complete engine work, just want the best bang for buck with increasing hp and performance, afr heads are $1500 alone, what about profiler-jegs heads, they flow almost as good as the afr and I could increase to 1.6 rockers for the same price as the afr heads, augiedoogy I don't have the clearance under my hood for high rise dual plane,
Safety Car
Joined: Oct 2004
Posts: 3,926
Likes: 739
From: Youngstown Ohio
Would be interesting to know peak rpm for TQ. My 383 had 373 rwhp also with 1 5/8" headers, 2 1/2" exhaust and stock mufflers. Mine had a 230/230 @ .050 hyd.roller cam and AFR 195s. However, peak rwtq was 456. This was at 4300 rpm, right where the converter flashes.
Drifting
Joined: Jul 2013
Posts: 1,299
Likes: 93
From: Tri-Cities TN
Yours is a good example as the AFR heads don't like much split as the exhaust port flows very well.
Drifting
Joined: Jul 2013
Posts: 1,299
Likes: 93
From: Tri-Cities TN