cahorne

My son and I converted a 6 cylinder car to a V8 this year and we took it to the track a few weeks ago. We have another race Sunday and are trying to make a few improvements and would like some opinions.

First Trip out it ran a 8.97 at almost 82 mph. 60' was a miserable 2.14. shifting at 6000RPM.

My first impressions was the 60' was way off and the car should be significantly faster I was thinking 8.50's. Secondly, I thought the mph was relatively high for that time. So how do we fix or improve on it.

First a little more about the car and how we had it tuned and how we launched it.

This is a stock 1987 302 short block with stock forged pistons. We added a Comp XE274 cam, Air Gap intake, headers, Holley 650 DP(67/73 jets). Headers 2.5 exhaust with X-pipe and flowmasters. DOE 351W heads with port work and 1.94/1.6 valves. We checked cranking compression the other night and are seeing about 150 psi. I believe the stock compression for the 87 302 was around 9.0. Initial timing was 18 and max was limited to 33. The transmission is a mildly built AOD with 4R70W components, Mechanical diode, Broader Performance valve body and a stock converter restalled to 2500. It actually stalls to about 2200. The rear end is 8.8 with 3.55 gears and a posi and 31 spline. We are running some pretty old 26X8.5 slicks.

The car pulled very hard and shifted very firm. The launch technique was 2000 RPM and go. Flashing did not work as the car was a dog unless I could get the RPM up quickly. We ran 15 psi on the slicks and they dead hooked.

CHANGES:

I think with iron heads we need more timing so I took the distributor apart and moved the stop so that we can now get 40 total. Its all in by 2500 RPM.

I want to increase the tire pressure to 16 to see if we can get them to make a turn or two off the line to help the car get in the power band a little faster.

I am thinking we should increase the jet size a little to see how it responds. This car is very rich in the idle circuit and I guess I need to check into drilling out the idle air bleeds.

The car has a little hesitation in the carb that I can't seem to solve, even though I have been through the pump, squirter air mixture routine a few times.

Suggestions: LETS HERE THEM

Ford Muscle Forums

hepcat69

i would definately bump the jet size up a bit, 71-71s in the front and maybe 75-78s in the secondaries. seems like a bit too much timing. usually set around 10-12 initial and 34-36 total. bump the psi up just a bit too. maybe start off at 19-20ish and come down until you hook. do you have any suspension work in the rear? other than that, it sounds like the car is plenty capable of your desired 8.50 range. just a little tuning and playing around. just take a timing light, some jets, and a tire gauge and play around with it. and remember, only change one element at a time so you know how your changes effect what aspect of the car's performance. good luck

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Happieness is defined as daylight under the front tires.

fordman460

X2 on changing one thing at a time. Use a log book to help notice what worked or didn't and the conditions at the time. Always check the float level first when messing with the carb. Just some of the stuff that helped me stay on track with adjustments. I will think of more!

hotrodder68

It sounds like a very similar combination as mine.

Mine is non roller 302, 270H comp cam, 670 Holley, Air Gap intake, GT40 heads from 93 cobra (1.85 and 1.5 valves), Broader C4 with 2200 stall and 4.11 gears on 235/60/14 street tires.

I had a 2.17 60' and ran a 9.05 at 78-79mph. I think with slicks I will be 8.70's or maybe better.

It sounds like our times are very similar except you are pulling more mph probably due to the more aggressive cam? I am not sure. I am running all timing in by 2800 with 10 initial and 38 total. I have heard 12 initial and 36 total would be better but I like this mechanical advance distributor better than my old duraspark for sure.


Any answer to your question will be a help to me as well. I want to hit the track again but would like to get down into the 8.7-8.9's next time for sure. I think just lowering the 60' time to a 2.0 or 1.9 would bring the et down .3 and you would be closer to 8.5. The speed bug is addicting though because now I am ready to build a 331-347 but need to just learn how to launch my 302 better and get the most out of it before moving on. You might also want to air up your front tires alot for less resistance. I have heard to take air cleaner off and sway bar too but who knows if it really helps. I will probably air up my front tires, borrow some slicks for the back, take out my spare tire, and cross my finger next time. I am running a 4.11 gear compared to your 3.55 but I am also using small little bgf radial t/a's and I spin a good amount off the line.

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306, AFR185,CR Camshaft, C4, 9'' 4.11 Detroit Locker

Brett Olson

Looser converter will get you up in the power band quicker. That will make the biggest improvement for you. Don't do it by trying to spin the tires. You may pick up MPH but you will lose E.T. Almost all of you E.T. is made in the first 60' so that needs to be solid. Lower rear gears will help also. What RPM do you cross the line. If your dead hooking now...DON"T DO ANYTHING TO CHANGE THAT. When you make changes, you need the car to hook to properly evaluate your changes. Do one change at a time and keep good records.

The tight converter is likely the source of the stumble off the line. You may find a temporary cure by incresing the squirter size. Start with the timing and find the sweet spot and then move on to the jetting. Change 2-3 sizes front and rear to start, then fine tune from there. Tune by MPH not E.T.

slow-poke

DOE 351W heads. We checked cranking compression the other night and are seeing about 150 psi. I believe the stock compression for the 87 302 was around 9.0.

Your compression might be lower than you think. Interesting to compare CC of the 87 302 heads to your 351W heads. I ran C9/D0 castings on a 289 and had to use a 12.5:1 dome piston to get 10.5:1 .

Initial timing was 18 and max was limited to 33.
Quicker curve will help, you might find that this engine wants a lot of timing, I ran a low compression (9:1) 351W with a Ford X303 cam and it made best power with 40deg advance. I would keep bumping it up 2 degrees at a time while observing ET, assuming your ET drops keep increasing the timing until ET slows, then back of 2 degrees. Don't exceed 40 deg.

Better converter would really help.

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65 Fastback: 530 HP N/A 408W, G-Force 5spd

frdnut

Definetly a good mph..My old 302 4 speed/4:11 combo would run 8.80s but only at a tick over 80mph...60fts were typically 2.05ish with a little wheelspin and launching around 4000rpm...A higher stall convertor would help you for sure..My jetting in the 650DP was 67/70 originally which worked fine with closed exhaust..Once I opened the headers I had a slight miss and ended up jetting up to 74/76 to finally clear it up..Probably still wasn't optimum but I had a limited number of jets and just played with it till the miss cleared up....Car looks great!

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1968 mustang 408W Hybrid..Burns gas and rubber!

cahorne

I think you are right on and we think similarly on timing. I have ran a few iron headed 289/302's and always found them to want a lot of timing. Right now I have it at 16 initial and 40 total with no pinging in overdrive.

The converter is definetely a non drag race part, but we did the best we could with the budget, It is better than a stock stall and since it is a street car primarily we will have to live with this converter until it becomes a second car and the gears and converter can both be changed. With regard to the compression the calculators I have used show about 9.0 based on a 60CC chamber, which is what I was told these are, unfortunately I did not CC them while I had the chance.

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6.75 @102 1/8 mile; 10.566@128.35 1/4 mile

cahorne

I think based on what you are saying and what others have said we are not too far off. I am used to low 1.50 60' in my car so I guess I thought his would be in the 1.8 area...wrong.... Anyway the idea behind letting the tires spin a turn or two is to get the RPM going. The car does not make enough torque to totally blister the tires. I guess I am using my experience with my car in that the car will 60' a little better with a turn or two of the tires vs dead hooking. I know it is a band aid for the tight converter but I think it is worth a try.

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6.75 @102 1/8 mile; 10.566@128.35 1/4 mile

cahorne

I read through your drag racing post with a lot of interest because of our similar combos. We should meet up at North Star one night for a little test and tune. I might even have a set of slicks you can borrow.

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6.75 @102 1/8 mile; 10.566@128.35 1/4 mile

68fastang

I wonder if it would lauch better flashing the convertor with the hesitation solved.I know all my auto buddies say they get the best results by flashing.
Your son is a lucky young man to have a great looking ride like that !!

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1968 Mustang 10.8 347,Canfield 195s,Vic Jr,750 HolleyHP,1-5/8 Hookers,TKO 500,4.33's
10.92@121.88 mph NA

hotrodder68

That sounds great. I would love to see what my car would do with slicks on a run or two. I am ready for a 2800-3000 converter for sure.

When funds free up I know the car would benefit from some drag radials, 2800 converter. I am not sure if I would see a change from different jetting but it is worth a shot.

It is a never ending quest...

Feel free to PM me or call me at 972 824 8885 if you want to meet up at North Star. I wouldn't mind going in the next 2-3 weeks with such nice weather.

-Nick

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306, AFR185,CR Camshaft, C4, 9'' 4.11 Detroit Locker