496 Drag Test REDO.............

[vortecpro]

As some of you know we ran this same test in the past when I lived in Colorado, well as usual we got totally screwed by the weather/conditions which made our 496 test a disaster, so I always wanted to redo the test in Texas, so that was the plan, not a year of dialing in the car, but a expedited drag test. One thing I've learned: although the specs look mild compared to a lot of 496 builds, this is a violent piece of machinery in the right hands and I had no idea living in Colorado what this engine is capable of, I knew what the numbers theoretically should equate to in performance. I built a lot of these monsters for people over the years!

The specs:
9.8 - 10.0 compression
GM 445 block
RPM 4340 crank 4.250 stroke
Sct 6.385 I beam rods
Mahle 19 cc pistons
781 GM oval port heads, 1.880/2.190 valves
238/248 578/608/110 hyd roller
Short travel lifters
Isky 8005 springs
Scorpions rocker arms
Rollmaster timing chain
Edelbrock Performer RPM air gap intake
4150 1000 com carb
1 inch open spacer
Milodon pan on this particular engine
Melling M 77 oil pump


The car: My 1968 Chevelle, T350 4.56 gear, (not optimum) 30x9 radial slick. Exact weight will be posted when I run across the scales Sunday.

The results from the first lackluster test were: 10.50 @ 124.5 140 60 foot, 6.61 660 @ 102 MPH Same engine this time drag tested in different conditions.

[67 Nova]

Good lucky Mark.

[vortecpro]

Good lucky Mark.

Thanks, working on it, should have last of the testing done today.
Little river drag strip 4/12/24. 4/13/24 so far
Track elevation 475 feet
76 degrees
Barometer uncorrected 29.68
54% humidity
+ 1558 Density altitude

So far I've been 107.3 MPH in the 660. I will go across the scales today for an exact running weight, somewhere around 3500-3570 I figure. The problem were having is tuning the front suspension to control the wheelies and still getting the car to hook on this marginal track. We are heading for the Concrete Palace today (Xtreme) but 2500-3000 DA is the problem, we got our work cut out.................

[Dave B]

I would think you could run 6.30 with that. Clear back in 90s we build 402 but had mech roller ,oval port heads .It ran 9.80s in old chevelle that was 3300 plus. We had old clutch/ turbo setup ,so it was violent as hell. Midwest air is good at 3000 da.Tdays converters and trans and tire compounds ,you should easily run what we did 34 yrs ago. With near 100 inch more under hood

[vortecpro]

I should mention the 496 in my test makes 650 STP corrected HP @ 6200 RPM.

[Stan Weiss]

I should mention the 496 in my test makes 650 STP corrected HP @ 6200 RPM.

Do you have a dyno sheet you can post? I was going to do a few simulations, this is what I have for your 496 from a few years ago.

Stan

vortecpro_496.gif

[vortecpro]

Stan

I don't know anything about the test you posted above, but here is the 496 dyno test data. You're only going to have 660 foot data to work with, thanks for your time. It would be great if Larry would like to contribute as well! Observed HP @ 6400 feet elevation was 460 HP 23.7 baro approx.

[GARY C]

Stan

I don't know anything about the test you posted above, but here is the 496 dyno test data. You're only going to have 660 foot data to work with, thanks for your time. It would be great if Larry would like to contribute as well! Observed HP @ 6400 feet elevation was 460 HP 23.7 baro approx.

Can you share converter info or are you keeping that under wraps?

[vortecpro]

Stan

I don't know anything about the test you posted above, but here is the 496 dyno test data. You're only going to have 660 foot data to work with, thanks for your time. It would be great if Larry would like to contribute as well! Observed HP @ 6400 feet elevation was 460 HP 23.7 baro approx.

Can you share converter info or are you keeping that under wraps?

I have a PTC 8 inch in there.

[Stan Weiss]

The car: My 1968 Chevelle, T350 4.56 gear, (not optimum) 30x9 radial slick. Exact weight will be posted when I run across the scales Sunday.

The results from the first lackluster test were: 10.50 @ 124.5 140 60 foot, 6.61 660 @ 102 MPH Same engine this time drag tested in different conditions.

Were you able to get a race ready weight?

Stan

[vortecpro]

The car: My 1968 Chevelle, T350 4.56 gear, (not optimum) 30x9 radial slick. Exact weight will be posted when I run across the scales Sunday.

The results from the first lackluster test were: 10.50 @ 124.5 140 60 foot, 6.61 660 @ 102 MPH Same engine this time drag tested in different conditions.

Were you able to get a race ready weight?

Stan

YES, The scales showed my all steel, factory interior, T350 12 bolt iron headed BBC weighed 3470 with me in it, no other scales have shown under 3500 pounds but go with 3470.

[Stan Weiss]

I used 3500 and guessed at a few things.

60 Foot ET = 1.3451
330 Foot ET = 4.0295
1/8 Mile ET = 6.3696
1/8 Mile MPH = 104.4593
1000 Foot ET = 8.4108
1/4 Mile ET = 10.1480
1/4 Mile MPH = 129.8599

In better air close to DA = 0
60 Foot ET = 1.3132
330 Foot ET = 3.9323
1/8 Mile ET = 6.2165
1/8 Mile MPH = 107.1885
1000 Foot ET = 8.2058
1/4 Mile ET = 9.9007
1/4 Mile MPH = 132.9607

Stan

[vortecpro]

I used 3500 and guessed at a few things.

60 Foot ET = 1.3451
330 Foot ET = 4.0295
1/8 Mile ET = 6.3696
1/8 Mile MPH = 104.4593
1000 Foot ET = 8.4108
1/4 Mile ET = 10.1480
1/4 Mile MPH = 129.8599

In better air close to DA = 0
60 Foot ET = 1.3132
330 Foot ET = 3.9323
1/8 Mile ET = 6.2165
1/8 Mile MPH = 107.1885
1000 Foot ET = 8.2058
1/4 Mile ET = 9.9007
1/4 Mile MPH = 132.9607

Stan

Thanks! What exactly is the difference in DA from those two runs?

[Stan Weiss]

I used 3500 and guessed at a few things.

60 Foot ET = 1.3451
330 Foot ET = 4.0295
1/8 Mile ET = 6.3696
1/8 Mile MPH = 104.4593
1000 Foot ET = 8.4108
1/4 Mile ET = 10.1480
1/4 Mile MPH = 129.8599

In better air close to DA = 0
60 Foot ET = 1.3132
330 Foot ET = 3.9323
1/8 Mile ET = 6.2165
1/8 Mile MPH = 107.1885
1000 Foot ET = 8.2058
1/4 Mile ET = 9.9007
1/4 Mile MPH = 132.9607

Stan

Thanks! What exactly is the difference in DA from those two runs?

The way I wrote my software I doesn't use DA. I take your CTq curve and use that. The second run was done with a dyno correction factor of 1.00 and the first run was done with a dyno correction factor of 1.08.

Stan

[vortecpro]

I used 3500 and guessed at a few things.

60 Foot ET = 1.3451
330 Foot ET = 4.0295
1/8 Mile ET = 6.3696
1/8 Mile MPH = 104.4593
1000 Foot ET = 8.4108
1/4 Mile ET = 10.1480
1/4 Mile MPH = 129.8599

In better air close to DA = 0
60 Foot ET = 1.3132
330 Foot ET = 3.9323
1/8 Mile ET = 6.2165
1/8 Mile MPH = 107.1885
1000 Foot ET = 8.2058
1/4 Mile ET = 9.9007
1/4 Mile MPH = 132.9607

Stan

What I need to know is this:

If I run 108.8 MPH @ 2000 DA in the 660, what would my MPH be in negative 400 DA conditions, this every important to me this information, thanks for your help! I will post the data tonight.

Thanks! What exactly is the difference in DA from those two runs?

The way I wrote my software I doesn't use DA. I take your CTq curve and use that. The second run was done with a dyno correction factor of 1.00 and the first run was done with a dyno correction factor of 1.08.

Stan