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Discussion Starter #1
Well, I took the plunge and ran a couple of 1/4 mile passes last night with the '67
(my first time ever). I can easily say it's the most fun I've had in a long time.
But of course, now I've got the inevitable question: How can I get more?

I turned a 16.84 (82.9 mph) and a 16.65 (83.45 mph). Using some basic math
formulas lifted from Car Craft, that calculates out to between 175 and 195 HP
at the rear wheels. I think there's a lot more in the car, but I'm not sure how to get
to it. I know my drivetrain is the weakest link in the chain, but would changing to
a higher stall converter and shorter rear gears give me more rear wheel HP?
Or would it simply change the shape of the power curve and just give me quicker
launches? I'm looking into getting some time on a dyno, but I'd like to get your
opinions first.


My buildup (couldn't fit it all in my profile)
Engine:
289 bored 0.060 to 298
flat top hypereutectic pistons (approx 10:1 CR with the stock heads)
stock 289 iron heads CNC ported by PowerHeads (1.90/1.64 valves)
CompCams roller tip 1.6 rockers
Isky Mega 264 cam (can't get the cam specs right now - Isky's site is down)
Performer (not RPM) intake
Edelbrock 1604 (600cfm) carb
MSD Ready-to-run billet dizzy w/Pertronix 40kv coil
14x2 open element air filter

Exhaust:
K-code manifolds
H-pipe
dual resonator/bidirectional muffler

Drivetrain:
stock C4
stock torque converter
stock 8" 2.79:1 open rear
 

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Do you have to 60 foot and 1000 foot splits. A 2.79 open rear usally is not a real performance type. Did you have traction problems and/or bogging? Since you have a C4, how did you choose shift points? I would suspect you spend a lot of time out of your power band and never used your topend HP.
 

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I agree that 3.55 gears will help. I would throw some headers at it also.

Prior to installing my RPM intake, T5 and slightly larger cam, my car registered a 14.6/98 on a G-tech. That was with stock valve, home ported heads. With the right rear end, I would think you would do the same or better.
 

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Discussion Starter #5
Run #1
60: 2.669
330: 7.235
1000: 14.140
1/4: 1.847

Run #2:
60: 2.550
330: 7.098
1000: 13.960
1/4: 16.651

No bogs, no wheel spin, WOT all the way and I let the C4 do the shifting.
At the line I kept the brake on with my left foot and run the motor up to
about 2000, released on the 2nd yellow. I have no tach in the car.
 

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Discussion Starter #7
My total advance is about 43 deg. and it's all in by about 2800 rpm. It's basically
the factory setup for the MSD dizzy. I'm running 22 deg of centrifugal advance,
15 deg of vac adavance and about 6 deg initial.

The exhaust is not stock, but it was available back in the day. I got it through
Mustangs Unlimited, it's pictured in their catalog. Basically it's the H-pipe
into two in-line resonators that both go through the same transverse muffler
mounted behind the rear end. I believe it's all 2" pipe.
 

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Discussion Starter #9
Hmmm. What did you use for weight numbers? According to my registration, my
curb weight is 3926, driver adds 320 (I know, I know....). Using 4226 for the weight
and 175 for HP, I get 16.8 for the ET, right in line with the track timeslips. Of
course, my setup is a long way from what that calculator is assuming...
 

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I agree, you need a 3.25 or 3.55. The 2.79 won't allow you to get the most out of the engine setup you have. New rear gears will make a world of difference.
 

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What do you mean by no whel spin? You are burning no rubber? If that's the case then that's not right. With your set-up you should be peeling the tires. 2.79:1 rear end's are bad, but there not that bad.

Greg.
 

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3926 seems a little high for weight considering a 66 coupe weighs 2760 LBS. I don't think they added 1,000 lbs to a 67.

I would double check your curb weight or look in your trunk?

Greg.
 

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I would suggest a starting point is timing. You're suggesting 43* total but are including vacuum advance in to that total, it should not be. You need to set/adjust your timing to ~36-38* total w/o vacuum. The line should be plugged when setting timing. A total of 38* could be comprised of 12* initial and 26* centrifugal. As always, the total advance is predicated on many factors, just insure no pining.

You mentioned 22* centrifugal + 6* initial. My guess is that you actually only getting ~ 28* total. The difference between 28* and 38* can make a hugh difference in performance on your set-up.

If you are unsure about the total advance under load, plug the vacuum advance, set the timing as described, and make a run w/o the vacuum advance. I suspect you'll see a big improvement.

good luck,


If you
 

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Discussion Starter #15
The only way I can break the tires loose is by goosing the gas around a corner.
I've yet to do any sort of burnout in this pony. And I'm running like 215's on stock
steel wheels. But I never expected to do burnouts with a 2.79.
 

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Discussion Starter #16
Well, maybe I'm missing something then. But when I measured the timing with a light, granted
it was under no load, I read over 40 deg of advance at about 3000 rpm. This jibed with the
sum of the vac, cent. and initial advance. Before I got the MSD dizzy, I had major detonation
problems and so had dialed back the initial timing to where it is now, between 6 and 8 deg.
But if I recall, the MSD manual said that the max available _centrifugal_ advance was
somewhere in the high 20s. To me, this suggests that the vac advance is alwasy contributing
to the total timing. What happens to vac under high RPM and WOT?
 

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What happens to the vacuum advance under load? That depends whether you use ported vacuum from the carb, or direct intake vacuum (my perference). It also depends on the stregnth of the vacuum diaphram in the canister. I'd disconnect the plug the vacuum, dial in 38* total and make a run. As always, check for pinging.

Another thing, you need to know what rpm you are running and shifting at. If you are letting the C4 shift automatically, you could be getting 4500rpm shift points. A sound motor should be good for 5500+rpm. BIG difference in 1/4 mile times..
 

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Your car is too heavy. should be closer to 3200 lbs than 3900 lbs.
You should be able to do a massive burnout with that set up. I can get smoke with my set up pretty eaisy: Tired 302 with stock cam, home ported heads, Edlebrock performer, Holley 600CFM, Hooker headers. H pipe, 2" exhaust, Electric fan( static fan deleted), MSD breakerless conversion and 2.79 rear with P225's

Check your tune and get a performance carb.
 

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The weight on your registration is most likely the gross vehicle weight (weight of car plus max load). I would guess the actual weight to be <3500lbs with driver. Plugging that into your calculation drives down the HP numbers, confirming a engine/tune problem.
 
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