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Just thought I would share my dyno results after I dropped in my new Holley carb. I didn't seem to find too many dyno figures for cars.
1969 427 390 Gross HP, based on my reading this would be around 310 Net HP at the flywheel, just an rough estimate ( maybe closer to the 300 figure)
The car dyno'd in a 246 RWHP with 1500 lb's of tractive force. I am unsure how translate tractive effort to torque
Dyno max HP reading was pulled in 3rd gear.
The car has a mild cam (Comp Cam K11-242-3 Cam kit), apart from that it is stock including original headers and 4 Speed M20 Box. The cams were installed 10 yrs ago.
So I estimate approximately a 20% drivetrain loss.
I still believe there is maybe a little more power to be had in this current setup perhaps 20 HP, I believe I have the original valve springs any may have some top end valve float.
It will dyno a bit higher in 4th gear, about 10 hp. 255 rwhp is about right for what you've got. I dynoed my '71 454 (360 hp gross, 285 net) back when it was all stock except a mild cam and got 250 rwhp in 4th gear.
I ran my 70 LS5 on a dynojet, mostly for diagnostics. It made 295 hp and 356 ft lb on 1st pull, and 286 hp and 369 ft lb on 2nd pull. I am currently running points ignition that was dying around 4600 rpm, which is why it was diagnostic session. Up until the spark died at 4600 AFR was good, and numbers were still climbing.
Running stock intake and carb. The stock heads got a little porting on both intake and exhaust. The valves are swirl polished ones all dumping into port matched exhaust manifolds going out stock diameter pipes to Dynomac Super turbo mufflers. The cam in unknown spec hydraulic flat tappet. Running replacement flywheel and stock m20 trans with stock accessories (water pump, alt, PS, AC) turning the fan clutch.
In in a couple weeks going to Pertronix ignition, and may run again to see how it does, depending on test drive.
I also dynod my 71BB last week. I got 394.04 HP@ 5180 RPM and 429.19 LB.Ft @ 5250 RPM. Using 89 Octane gas and 95F ambient temperature. I found it kinda disappointing first but according to the dyno guy, was not bad at all. What you guys think? 454 + 0.030 Original motor, 10.00:1 CR, Oval Alum heads, Mild cam, A/C, Hydroboost, P/S and Fair Idle. 0.567/0.578 lift 224.6/230.6 Duration.
pretty good actually, considering it has a smallish cam.
Had a mild 460 in an 85 stang, , ran 11s but never hit the 400rwhp mark. Broad torqueband/proper gear!
My 69 427 with Headers and cam as the only modifications made 330RWHP and 399RWTQ before I stroked it to a 496. The 496 with roller cam, aluminum heads and Holley DP and LS6 intake made 440RWHP and 500RWTQ.
Been told my cam is way too mild of duration. But I can drive it in traffic while enjoying A/C and making 17 inches of vacuum at idle. I like to have some lower end torque.
Just thought I would share my dyno results after I dropped in my new Holley carb. I didn't seem to find too many dyno figures for cars.
1969 427 390 Gross HP, based on my reading this would be around 310 Net HP at the flywheel, just an rough estimate ( maybe closer to the 300 figure)
The car dyno'd in a 246 RWHP with 1500 lb's of tractive force. I am unsure how translate tractive effort to torque
Dyno max HP reading was pulled in 3rd gear.
The car has a mild cam (Comp Cam K11-242-3 Cam kit), apart from that it is stock including original headers and 4 Speed M20 Box. The cams were installed 10 yrs ago.
So I estimate approximately a 20% drivetrain loss.
I still believe there is maybe a little more power to be had in this current setup perhaps 20 HP, I believe I have the original valve springs any may have some top end valve float.
Thanks,
NJ
As many mentioned, your numbers aren't bad.... A 4th gear pull would have been better but... I would also be very suspect of stock valve springs....That being said, even a healthy stock LS5 is DONE making power by 5000 rpms...
I have a mild 454 in one of my other cars and even with lightly ported oval ports, old school Comp 270H cam and a Performer intake, it is DONE by 5200...
You can definitely count on 18-20% drivetrain loss in a C3, especially if it has full accessories and a 7 blade clutch fan.... My auto car calculated out to 30% loss...and I've been on 2 engine dynos and a chasis dyno to calculate the loss.
I also dynod my 71BB last week. I got 394.04 HP@ 5180 RPM and 429.19 LB.Ft @ 5250 RPM. Using 89 Octane gas and 95F ambient temperature. I found it kinda disappointing first but according to the dyno guy, was not bad at all. What you guys think? 454 + 0.030 Original motor, 10.00:1 CR, Oval Alum heads, Mild cam, A/C, Hydroboost, P/S and Fair Idle. 0.567/0.578 lift 224.6/230.6 Duration.
That is outstanding numbers for your combination honestly.....
My 69 427 with Headers and cam as the only modifications made 330RWHP and 399RWTQ before I stroked it to a 496. The 496 with roller cam, aluminum heads and Holley DP and LS6 intake made 440RWHP and 500RWTQ.
NJey1985- Some of the other posters here helped me when I was checking my dyno performance about a year ago on my 68 convert with NOM 454. Definitely look at upgrading your valve springs to squeeze out a few more rpms. A set of medium priced roller rockers will also help and are an easy installation. Obviously a bigger cam will help. I recently removed my belt driven fan, since I also had an electric fan on my aluminum radiator and just the fan change gave 15 rwhp. It's easy to get hooked on "dyno racing", but if you enjoy doing the mechanical work and if your budget allows it, you can have some fun seeing what more you can get out of your engine. Good luck.
The dyno sheet from my diagnostic session. Ignition was dying around 45-4700. Was only running 8 deg initial timing, and could have gone higher but wasn’t the point. I will be installing my points eliminator kit soon (ordered today) and will hopefully cure the problem.
08-31-2018, 07:16 AM
1969 427 390 Dyno Results
