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Discussion Starter · #1 ·
I have a 75 Mustang II that weighs 2900 with driver. It has an 8" with 4.11 gears, a manual shift C4 with an Art Carr 4500 9" convertor (spragless). The engine is a 302 with KB116 .200 domes, Edlebrock Performer RPM heads (2.02/1.60 Valves), 1 1/2" headers (long tubes) with 3" exhaust to the rear axle and Hooker aero chamber mufflers, Stealth intake with a 1" 4 hole spacer and a 4150 750cfm holley. The cam is a Clay Smith solid flat tappet with 304* adv. Duration, 258* @ .050, .560 lift and 106* lobe center installed +4*.

What do you think it will run? both 1/8 or 1/4 mile. Will be taking it to Texas Motorplex this weekend for some racing.

The old combo was the same of everything except the cam which was a Lunati Bracket master II cam with 292* adv., 230* @ .050, .512 lift and 110* lobe center installed straight up. The car was running 12.70's
 

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1/4 mile 12.55s probably, your headers are to small in the primary side. You need at least 1 5/8", 1 3/4" would be better. 1 5/8" would probably get you into the 12.2s. Lots of over factors. Tires, track surface, driver skill, weather.
 

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Wow, big change in camshaft... if you're ok with shifting at about 8000, I'd have to agree with dacofa and guess about 12.5... and also agree on the headers, a little on the small side for something turning that kind of RPM... everything else in the combo looks awesome though. What kind of valvetrain components and crank/rods are in it?
 

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What compression? What kind of 60 ft. has it pulled? Does it really stall at 4,500?
 

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Tires, track surface, driver skill, weather.
Don't think driver skill should be a problem with Mr. Econodrag.
 

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i had a 306 with a set of mild ported DOOE 351 heads,victor jr intake, slive claw 650 carb, madden flat tappet cam ,11.3 comp, 1-3/4 headers. the car weight 3100 pounds. the car ran a best of [email protected] with 1.58 60 ft also the car was ran with mufflers and d.o.t tires. so i think you should run high 11.'s
 

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Discussion Starter · #7 ·
On 2006-05-04 22:32, dacofa wrote:
1/4 mile 12.55s probably, your headers are to small in the primary side. You need at least 1 5/8", 1 3/4" would be better. 1 5/8" would probably get you into the 12.2s. Lots of over factors. Tires, track surface, driver skill, weather.
The 1 1/2 headers are all that is avaliable for the car until I can afford to get some custom headers built for the car.
 

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Discussion Starter · #8 ·
On 2006-05-05 00:07, 289nate wrote:
What compression? What kind of 60 ft. has it pulled? Does it really stall at 4,500?
The compression is around 11:1 and the convertor was changed from a 3200 to a 4500 stall. Previous 60 foots were in the high 1.70's and low 1.80's. The convertor will stall 4500 behind the 510hp 306 in the Cougar so I'm figuring it will stall around 4000 in the Mustang II.
 

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What are you running for tires?
 

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Discussion Starter · #10 ·
On 2006-05-04 23:12, Motorhead wrote:
Wow, big change in camshaft... if you're ok with shifting at about 8000, I'd have to agree with dacofa and guess about 12.5... and also agree on the headers, a little on the small side for something turning that kind of RPM... everything else in the combo looks awesome though. What kind of valvetrain components and crank/rods are in it?
Wow! How did you come up with a 8000 rpm shifting point? We will likley be shifting the car around 6500. The bottom end of the engine is stock as far as I can tell with the exception of the pistons. The valve train is double springe with damper set @ 130# seat pressure and full roller rockers. I bought the car from a local racer over the winter. When I got the car it ran mid 8's in the 1/8th so I installed the RPM heads and it went to the 7.80's in the 1/8th. I'm working towards getting so custom fender well headers made for the car.
 

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Discussion Starter · #11 ·
On 2006-05-05 07:01, dfree383 wrote:
What are you running for tires?
26x8.5x15 M/T slicks on 8' draglites and front runners.
The car also has SSM bars, frame connectors, Strange 10 way rear shocks and Comp. Engr. 3 way front shocks.
 

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You have totaly changed the motor with the cam you selected its going to need More Gear to go faster (4.56/4.8
and a little taller tire if you can fit it 28's would probably help your 60' times. IMO You havent stated if you are using a transbreak or not? I"m not sure if changing the cam is going to help your times any and it may hurt it.
 

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looking over everything again you may want to start thinking about a Victor JR. The RPM range for the cam you have now is going to be more suited for a single plane. I would guess you may be looking at a 7000-7500 shift point now. Your starting to move into race car territory.

1) Bigger Headers (at least 1 5/8 - 1 3/4 perfered)
2) more gear (4.56 or 4.8

3) Single Plane (Victor Jr.)
4) Taller Tires (2

5) Transbrake

I would guess the cars potential is at least in the low 11's maybe high 10's if you can get it to stick. IMO


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1984 Mustang GT 460, Powerglide "Still putting it together" hoping for 9's !!
1929 T-Altered "In the works" 8's are on the horizon



<font size=-1>[ This Message was edited by: dfree383 on 5/6/06 12:12am ]</font>

<font size=-1>[ This Message was edited by: dfree383 on 5/6/06 12:12am ]</font>
 

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I think 6500-6700 will be max shift point with that combo. Im guessing you shifted around 6000-6200 rpm with old cam? Im gonna guess at least .3 -.5 reduction in ET from the 12.70 number if running the same air and track surface. Should MPH about 2-3 better....but I dont see your previous mph mentioned. I think all the gain will be on the big end. Of course the timing and fuel tune made need some tweaking too
 

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The tight 106 degree lobe seperation -might- be your saving grace, as long as those small headers aren't too small to keep the scavenging from working right. The Stealth intake will probably limit things up top, but may allow for a better launch.

I see maybe a couple tenths, but not much of an improvement until you can add a Victor Jr intake and better headers. That cam should want a significantly higher shift point than 6500 rpm. I would think it would want at least 7500 rpm, as my small solid (236/248 @ 0.050" with a 110 lobe seperation) wants shifted at 6800. Maybe the tight 106 LSA will bring the powerband down a bit, but it will really come into it's own when the bigger intake and headers allow it to rev on up a bit more.

The converter is another wildcard. The old cam would probably pick up quite a bit on launch with it as well.

However it runs this weekend, have fun!
 

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Discussion Starter · #16 ·
We are going to start this thing shifting @ 6200 and work from there. With the previous cam we was shifting @ 5600 considering it was a hydrulic cam and was pretty much dead over 6000. I think the Performer RPM heads will have no advantage over 6500 RPm's. I will update with times on Sunday night.
 

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Discussion Starter · #18 ·
Ok the results are in. The best et that the car ran was an 12.45 @ 104.5 mph with 2000ft D/A and a 5-10 mph head wind. The 60 foots showed the greatest improvments going from the low 1.90's to the low 1.60's. But since this car is a bracket only car the real susprise is the car made 11 passes over the weekend and with the exception of a couple of passes every 1/8th mile ET was a 7.83 and onc e the driver got settled in to a grove the 1/4 mile times were all in the low 12.50's. Oh...... and we started shifting the car at 6200 rpms and turned the shift point down to 5800 rpm's. I think with bigger headers and a single plane intake the car has potential of going in the 11's but for now running the same ET every round is more important.
 

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Cool to hear !! Sound like a couple more upgrades in the future !!
 

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On 2006-05-05 07:04, econodrag wrote:
Wow! How did you come up with a 8000 rpm shifting point? We will likley be shifting the car around 6500.
I was just considering the fact that I have a more mild combo (289 with 1.94 valve Windsor Jr. iron heads, 9.3:1 comp, 232 @ .050 camshaft, Xcelerator intake, 1.5" headers) and mine likes to be shifted at 7400rpm, and makes peak power at about 6400. The fact that you are running 2.02 valve aluminum heads with a cam that is over 20 degrees more duration tells me that it should make power at even higher RPM than my setup. I think the fact that you're only running it up to 6000 tells me you gave up some ET with the cam swap... I mean you gained 3 tenths off the line, that should've been an easy 6 tenths at the end of the track right? The intake must really be holding it back if it likes to be shifted that low...

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<font size=-1>[ This Message was edited by: Motorhead on 5/9/06 12:34am ]</font>
 
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