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Discussion Starter #1
Here is the build...

1973 Mach 1 (3680 with me in it, no gas)

351 C, .03 over, cast flat tops, 4v QUENCH heads (10.6:1 or abouts?), torker intake, holley 750 VS, Cam is 32-638-5 (comp) specs are: I 246* E 256* both at .05. I is .564" E is .589". Hooker super comps 1 7/8 Primaries, 3" Collector, 3" exhaust 2 Chamber Flow masters. C6 Trans 3500 Stall. Posi 4.11's.

After the 4.11's and Posi, I thought I would have ran a whole hell of a lot better then what I did. My previous best of 14.7 with 3.25 Open dif was beat, but not by what I thought it was going to be beat by. I shifted with my previous best at 5800 RPMs. I used the same tires as before (Not slicks). here is this best time. Today I shifted at 6500 RPMs. I launched at around 2700 RPMs. Any more and the tires would spin (atleast I think that they were) never seemed to do that with the 3.25 Open.

60' 2.909
330' 6.135
1/8 9.168 @81.70
1000 11.787
1/4 13.998 @ 102.16

I just dont get it.
I thought I have heard I could expect mid to low 12's. I barely was able to muster up a 13 second pass....I though well, if I get the 60' down to where this Camaro was (I race it this race) of 1.744 that would help me b over a half second, but still, the MPH is not high....not at all. I am really bumming...I think I need to go drink my sorrows away now...


Nothing REALLY good came out of today....cheer me up, and help me out!

Jeff Given
 

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lower gears, the 351c likes alot of rpm's
 

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What kind of rear tire have ya got? That 60ft. needs some work. What was the finish line RPM? Sounds like all ya need are the right tires.
 

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Discussion Starter #4
OOPS the 60' is 2.309 not 2.909!!

I cant really go too much higher on the gears, for 2 reasons. 1. I already bought the 4.11s, and 2. I have cast pistons, and giving it more RPM could be a catastrophe! What would be a GOOD, REASONABLE goal of a 60' with traction bars, and slicks? Man am i bummed....my dad keeps telling me we will get it down...but 12's almost seem way too far out of reach now....big time bumming now...

Jeff Given
 

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I wouldn't be bumming taking off .8 in your ET with just a gear change. that's a good drop. I agree now that you have gears you need tires to match. Go get that Slomaro.
 

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You have to remember that your working with a heavy car. Try a set of 26X10, or 28X9 slicks on an 8 in. rim. Forget putting tubes in them also. For racing the tubes are just added rotational weight.
Disconnect the front swaybar end links. This will help with the weight transfer. Shocks are another item that can be changed to help with the traction problem. CE makes a drag shock thats not too expensive. They could be added after the rear tires.
You really NEED the tires first. I'll bet it'll run 13.60's with good tires.
 

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I agree with 85Mike. Get the traction issues out of the way, then start tuning on it(carb jetting, timing, plug gap etc.) . With 102.6mph trap speed you are only making around 300-310 hp at the wheels. Would think it should be more like 350hp, that will get you a 12 sec. timeslip for sure.

My 5.0 Bird has trapped 105.3 and weighs 3750 with me in it. Your Cleveland ought to make more power than a 5.0.
 

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I'd agree with the rest of the post's regarding traction. The MPH is a very good indicator of actual rear wheel horse power. If you have, or have a friend with a video camera take it to the track and have them record the launch; with you recording various launch rpm's etc. Then you can compare time slips to the video and track changes in tire pressure etc. Summit sells a cheap log book. June 2000 Car Craft had a great track tuning article where they picked up .8 and 2 MPH with basic tuning.
 

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It definatley needs slicks. And I'm sure you dont want to hear this, but it also needs a looser convertor. My 70 fastback, with a motor combo very similar to yours, clear down to the C6 and 4.11's, ran 12.60's all day long on a 10.5 wide slick. Difference's were I had 1 3/4" headers, a slightly smaller cam (235*, 245* @ .050) and I had a 4200 stall 10" convertor. And I was shifting at 6500 also. The car normally ran low 1.70 60' times.

The CE drag shocks would also help. They're not a bad shock, I ran the same part number shock on my drag granada.
 

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Similar story to Greg Cooks.
Many years ago when I raced my brand X car, I wanted to see how quick it was 'thru the pipes' and on street tires.
It went 12.70's slipping and sliding thru 2nd gear. Kind of a scary ride. In either case, bolted on the slicks, (not huge, mind you, only 10.5's), and went 11.'s. Unbolted the pipes, and went 11.5's..........hmmmmmmmmmmm
 

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What size tire and brand do you have on there now? What are your rpm's as you get to the 1/4 mile mark?
But with a slick you can raise your launch rpm and lower those 60ft times and your 1/4 times.
 

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My racecar runs mid 1.30 60' times and runs low 10's. On the 9 second pass it had a 1.344 60' time. This year I'm leaning towards taking my c4 out and replacing it with a powerglide to try and calm down the launch a little. With the right convertor the et should stay about the same but the 60' will be slower and hopefully not quite so violent and therefore more consistent.

I would think even if you could get your car into the mid 1.80 range it should still get into the 12's easy enuff (around 12.80 or so).
 

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Discussion Starter #16
okay....shooting for 1.8 second 60' times. As for the end RPM I did not even think to look...so I am not sure


Jeff Given

Ohh yea...what is a good slick that can be drive on the street....I wont EVER drive it on the street, but has to be "street Legal". When I get to the track, I will put them on. Thanks a lot!

Jeff Given
 

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You'll want a 26" slick, not the 28". This will give you a more effective gear ratio at the strip. You don't need anything huge either... anything between 8 and 10 inches wide will be plenty.

Yes, the MPH seems awfully low. My guess is the exhaust is a problem. 351C's NEED a free flowing exhaust. A buddy of mine picked up over a full second in the 1/4 by going with a free flowing exhaust. His exhaust consists of cheapo $79 Dynomax headers, 3" exhaust w/flowmasters, and turndowns. (no tailpipes) It sounds tough, and runs great!

If you need nothing smaller than 2.5" pipe. If you have 2.5", and are running tailpipes, you'll NEED flowmaster MANDREL BENT tailpipes. These are only $99 at Summit, and are the best hundred bucks you'll spend on the car. Muffler shops CANNOT do mandrel bending. They crush and kink the pipe where it's bent. The tight bends of a tailpipe crush the living daylights out of it. The Flowmaster pipes fit 64-73 stangs. Get em' if you insist on running tailpipes.

Get a set of 26" slicks and a GOOD exhaust, then launch the car HARD, and it will 60ft in the 1.7's and the car will perform to your expectations....

Until then, your just making noise and spinning your wheels.


Good Luck!
 

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I've run the Quick Time Pro's for two years now. On MY car they work as well as slicks do. I use the 27X11.5's. You should try the 26x11.5's. Jeg's has them.
Don't forget to unhook that front swaybar.
 
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