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Get Mach1 into 12.5 second zone
#1
Hi all
Does anyone here drag their 71-73?

With stockish 429, mild cam, headers, toploader, 3.5:1 axle & Quick Times I got my Mach1 down to 14.11 @ 98mph. Fun but hardly impressive!

I'd like to get it into the 12.5 second zone with either 351C or 460 and still be streetable. Anyone got a car running around this level that can give me some suggestions?

Regards
Dunc
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#2
Stock 71 351C-4V w/4 speed, 3.70 gears, 214/224 .510/.536 cam was good for 13.5. You should be able to crack into the 12s with that 429 with a rebuild and a more aggressive cam.


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#3
You can't have your cake and eat it...

What was your 60' time?

I would think the easiest starting point would be adding more gear and a locking differential. How much rear tire do you have?

Jeff's (his user name escapes me) car runs pretty hard if I remember, he could probably give you some suspension pointers. Your issue will be getting that 429's grunt to the pavement without going up in smoke.
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#4
I don't know a lot that would be helpful as I am not familiar with your car. That being said to run mid 12's in a 3700 pound car you need about 450 horsepower and pretty close to perfect driving technique on the track.

My 2015 Mustang GT with no engine mods can run as low as 13.3 (so far) but that is me beating the hell out of it with the traction control turned off, but that engine lacks torque at the bottom end and it just is hard to launch consistently due to soft bushings in the rear suspension. My 73 is over 600 HP and has yet to run a true 1/4 due to fuel issues. My fuel pump just can't keep up. Larger pump, lines and probably a fuel cell are in the works. I did get an 1/8th mile run in at 7.285 but my reaction time was poor and I was running out of gas at the lights

Tires. You need good tires with lots of footprint to hook up and go fast. Stick shift cars typically run better with bias ply drag tires and tubes. Automatic cars do fine with the Drag Radials. I run drag radials and a stick and it is really easy to spin more than intended. More tire is more betterer. Wink Tire pressure should be far lower than on the street.

Traction device- I like the Cal Tracs, but there are a ton of ways to do it. I like the Cal tracs because they are easy to adjust and don't result in changes to the car that can't be undone. If you don't have frame connectors, get them, the stress of a hard launch can twist the body.

Launch hard, leave fast you can't get those times unless you are driving the car hard. This means also that you are going to find weak links. Get a new driveshaft and yokes if you aren't already running at least a 1350 U joints and run the ones without grease zerk fittings, the fitting makes a weak point in the body of the u joint. Aftermarket axles get real close to necessary when you get to this power level.

lower gear ratios such a 3.89, 4.10 or 4.30 are just about entry level for drag cars.

Make sure you have a good rev limiter, esp if you drive a manual transmissioned car.

Lose weight, no need to have a spare tire in the car when you run, or anything else that you can leave out, like the passenger seat

Drag racing shocks do help with weight transfer, but I would not drive on the street with them-some people do and swear that it is not a problem.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#5
I will be putting the 351C back in over the winter. It now has 10.5:1 static cr with a Lunati cam of around 0.55" lift & 235 degrees duration with a Performer Air Gap & 750 or 850 Holley. It should run fairly strong I would think.

My thoughts on the 429 involve converting to 460, Icon flat tops for 11:1cr & a Comp Cams 274XE. But that will be later in 2018 or 2019.

I have been thinking about putting 3.89:1 gears in the rear as the tires I use on the track are Hoosier Quick Times in 275/60/15 which are over 28" tall. This would put gearing back to how it currently is on my street tires of 235/60/15 with 3.5:1. I can tell the difference in acceleration but it needs the QTs to hook. Maybe I should have bought 275/50/15 QTs.

60" times have been consistent around 2.3 seconds. I learned to baby the car off the line before getting the QTs and I have not dared dump the clutch hard yet for fear of twisting the smallblock size input shaft. I have a torque biasing diff.
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#6
Your launch is holding you back, though your reasoning is sound. Your 60 foot times should be down in the 1.6-1.7 range to get to the times you want. The toploader is pretty stout and while you might twist an input shaft it is more likely to would brake a u-joint. If you do not have a driveshaft safety loop, you need to get and install a good one before doing a clutch dump. A front u joint failure without a safety loop can cause the shaft to come up through the floor and cause horrific injuries.

I think your tire choice was fine.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#7
Thanks Jeff, some good advice. I do have a safety loop & Strange S/S 31 spline shafts. I also just bought a 1 3/8" input shaft to swap in when I change engine. I think I will take a look at the prop ujs. Cal tracs would be good I guess as all the 10 - 11 second Super Stockers use them round here. I didn't think my car would be fast enough to benefit much over ordinary traction bars. Frame connectors sound good.
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#8
Wouldn't the simplest, cheapest, quickest way to get lower times would be to use a shorter track? You'd be halfway there! Just sayin'...

Let me check your shorts!
http://midlifeharness.com

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#9
(11-02-2017, 06:05 PM)midlife Wrote: Wouldn't the simplest, cheapest, quickest way to get lower times would be to use a shorter track?  You'd be halfway there!  Just sayin'...

The math checks out  thumb

What's the compression of the stockish 429? The simplest (on paper) ways would be more bang in the cylinders either by running the thinnest head gasket you can for a compression bump or getting a cheap nitrous kit. A small nitrous shot (<100 shot) is relatively safe on any engine, especially if you have less compression than desirable (I would assume you are in the 8-9 static CR range based on the ET).
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#10
(11-02-2017, 05:51 PM)Duncan Mach72 Wrote: Thanks Jeff, some good advice. I do have a safety loop & Strange S/S 31 spline shafts. I also just bought a 1 3/8" input shaft to swap in when I change engine. I think I will take a look at the prop ujs. Cal tracs would be good I guess as all the 10 - 11 second Super Stockers use them round here. I didn't think my car would be fast enough to benefit much over ordinary traction bars. Frame connectors sound good.

Just a thought, I'm still running a small input shaft transmission and have dumped the clutch more than a time or two.  So far no twisting issues for me.  I suspect your current power level is low eenough that you would be fine to give it a good hard run.

As to Caltracs, I think they are better, but that does not negate the value of other traction bars underide and slapper bars  work well for many people

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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