Carbureted 302 Dinosaur drag performance help

gearheadmn · 07-06-2003

Greetings, all. I am a long time drag racer, but haven't done much Ford racing work. I have a friend who just completed at Mustang II 302, which we ran on the 1/8th mile for the first time yesterday. Results: 9.0 at 80 MPH

. Not what he expected. He built this engine with the "advice" of others, before contacting me. I already have been given some possible input on this, but "there is wisdom in many counselors"

.
2900 lb. car w. 302-.030 over, 14-1 compression, 1966 289 heads, 2.02 intake valves, (don't know ex. size), amatuer porting, 260 deg. duration at .050, .565 lift, 110 lobe centerline, 4,000 stall, c-4 trans, 3.80 gears, 28 inch tires.
Thank you all in advance for your assistance.

Fordgazm · 07-06-2003

is this an alcohol motor ??And what carb and intake ?? Does the car run strong and well ?

gearheadmn · 07-07-2003

Whoops, I guess that I did forget a couple of details. 780 vacuum secondary on gasoline, Twisted Torker intake with 1 inch 4 hole spacer under the carb. I also need to edit the tire size to **24** inch, not 28. 60 foot times were 2.0. The engine ran clean up to 6,000, then fell flat to about 6,300 before coming back to life again. The shift point was 6,500, though I'm not sure exactly when the trans actually completed the shift. Theoretically this cam should pull to 7,000 +. Fuel pressure is good when not moving, (don't have a gauge visible while driving). 3/8 line all the way forward including the pickup tube, electric fuel pump of some sort in front of the tank, regulator set to 7psi. Bumped up primary jetting to 74, sec. to 78. Plugs still look lean. Went from lightest to heaviest secondary springs with very little change in e.t.
**Also**: Found out that ex. valves are 1.6 inch.

Fordgazm · 07-07-2003

I believe the problem lies in the fuel . What octane is the gas ? 14to 1 is way high for a gas motor 14 to 1 is more like ethanol/alcohol territory . witch would explain the lean plug condition . Anyone else have any ideas ?

gearheadmn · 07-08-2003

I believe that he is running 110 octane, (maybe 114?), and that could certainly be a factor. In fact, I'm a little bit concerned about this horse detonating itself to death. I was also hoping to get some input on the engine combo., from a Ford persons point of view.

Fordgazm · 07-08-2003

I would try to get higher octane fuel , a double pumper carb , bump up the timing and see what all happens ...The rest of the combo seems ok . What kind of lifters is he using ? And are the valve springs correct for the cam ?

gearheadmn · 07-09-2003

I'm not sure what kind of lifters, or if they have any special bleed-down qualities or anything. I believe that the springs are matched well to the cam. The engine builder seems pretty sharp, and didn't totally agree with my friends cam selection right from the start. Anyway, after 3-4 days of frantic research by both of us, he's decided to go to a smaller cam. On a computer dyno, the new cam is building 300 lb/ft of torque by 2,000 RPM, as opposed to 120 with the existing cam. Much better for such a small cube engine in a middleweight car. I'm also convinced that the main jets are still way too small for the compression ratio. Even if we kept the existing cam, I'm convinced that more jetting would wake it up significantly. I'm still not sure about octane. I do need to follow up on that. As far as ignition timing, the engine seemed to run best at about 34-36 total with the current jetting. We ran it up as high as 40, which it did not like at all. Again, richer jetting/higher octane may make a difference there. Thanks for the input.

ro51468 · 07-09-2003

As mentioned here in prior posts, your fuel could be one problem. Take a look at www.vpracingfuels.com and specifically at their C14 that is suggested for 14.1 C/R motors. It also sound like one or 2 things might be happening at the top end, with the most likely being running out of fuel. It sounds like the pump does catch up because you mention it picks back up. As far as spinning to 7000, with the limitation of those heads it may just run out of steam.

What is his RPM at the top end of the track? Crossing the line?

Ron

Lowet · 07-10-2003

I think I would try to bump up the fuel pressure, that carb. should be plenty big the vac.sec. will need to be tuned with that size cam, in that car I think I would run a solid lifter cam with a split dur. but as you said with less total duration. 280-296 advertised ? Good luck with the combo it should screem when he gets it tuned.

gearheadmn · 07-10-2003

Thanks for the input, people. The flow capacity of the heads has been one of my main areas of concern, based on input from other sources. Hence the change to a cam with less lift and slightly less duration. I do think the split duration would probably be the hot tip, but as of this moment the budget dictates the purchase of a used cam with even numbers which will still vastly outperform the existing cam. I will definitely see that we research the fuel quality issue also. Thank you very much for the tip concerning the VP fuels sight. I never even thought of searching there. I will hopefully give updates some time within the next 2-4 weeks to let you know how it all worked out.