Engine What Cam? 289

Discussion in 'Classic Mustang Specific Tech' started by 65FBE2, Sep 8, 2012.

  1. i dont think the cam is the problem, unless you have a wiped lobe or another valvetrain problem. id replace that carburetor. holleys are junk too. the combo actually looks pretty good, except i would put one of these carbs on it.....


    the difference will be night and day.
  2. I think the rear end gears need a little more go-go, 3.5 or a little lower. Also, sounds like a valve train issues if it won't rev over 4200. Have you checked the valve spring requirements and made sure they are up to the task? Also, could the pushrods be bumping or rubbing anything? Wiped lobe is an interesting possibility also.

    Sounds like airflow through the carb and heads should not be the problem.
  3. there is a lot more to carbs than just airflow and jetting. putting more gear in wont help it not noseover at 4200 rpm. if there isnt a valvetrain problem, its likely the carb because that combo should easily pull past 6k.
  4. No the gear won't help the engine run over 4200, for a 289, I'd put more gear in a rear end, that's all. It should not effect gas mileage that much.
  5. Hmmm… I'm a big fan of the C9OZ-6250-C cam, too.

    Your gearing and axle ratio should be excellent. the carb should be a good match, as long as it's working right.

    The F4B intake was Edelbrock's copy of the Cobra high-rise, which is a pretty good intake even by today's standards. If yours is a Performer RPM, you'll be fine, but if it's the plain Performer, it's no better than the stock iron intake, inferior to the RPM or F4B.

    Your cam, I believe is the Comp Dual with Advertised Duration 265/273, Lift .472/.486, is roughly comparable to the C9OZ-C. A guy near here used a similar setup, with the C9OZ-C. Port-matched his iron heads, stock distributor tuned to BOSS 302 specs. Engine turned 323.5 hp @ 5300 rpm.

    Pony Carbs was capable of excellent work, it was their customer service that sucked.

    What distributor are you using?
  6. 65FBE2,
    Here's a dumb question: Are you certain that your throttle/carburetor is opening fully? I could be as simple as an incorrectly adjusted throttle rod.
    My $.02,
  7. Ok, so here is what I am going to try, I just ordered a Blue Thunder Cobra intake to keep the engine looking period correct. I have a 750 HP carb from my last project just sitting here so I am going to try that. I'm sure it's to large but it should answer the question if its a carb problem. I will let you all know the out come. By the way, the motor nose over at 4600 but will keep reving. I don't go past 6000. But the power just seems to stop about 4500 rpm. The rear gear is fine as is. In fact I switched from a WC T5 to a T5Z tranny just to get the 2.95 first. The 3.35 was just to low to be good for much unless I was drag racing. That's not my intent. I own a Infinity G37 as my daily and I want this thing to be somewhat near the same power level. Right now I would say its 100 HP less.
    I am using the stock distributor with Petronixs I. All the advances are working. I have timing set at 34 total 15 initial. Has anyone had an issue with this distributor?
  8. I like the Pertronics way better than points, so I think that's a good choice. If you have an ignition problem you should get stuttering or the engine cutting out at high rpm. You haven't described those symptoms so I would guess it isn't an ignition problem. I agree with the others that point toward the intake - my understanding is the Performer isn't very good. Between swapping intakes and the carb you should learn a lot. However, before you spend more money you should really look at the numbers and details. Look up the Performer flow information, compare to your head - that will tell you if the intake really should be limiting you. I guess now you should be looking at the flow numbers for the Blue Thunder Cobra intake and comparing those to your head flow numbers. If you want the stock look have the intake ported so the flow matches your heads.

    If you make the changes to the intake and carb and don't see an improvement I think you should look at everything. You say you had the heads ported. What do they flow and how many cc are the intake ports? You need to have all the parts in the pathway be matched to each other, so you should know these details in order to make the engine work as well as possible. Headers would be a much better choice than stock exhaust manifolds to get good performance. You say the cam was installed by pros - I would check it anyway. Make sure it is installed degreed correctly. You can check the oil to make sure a cam lobe hasn't been wiped, but based on the symptoms you describe - just running out of steam at ~4,500 rpm - I don't think that's the problem.

    I don't think you need gears with a manual transmission 3.25 aren't bad. Your problem should be more getting traction. A 289 with any sort of well-matched mild performance upgrades should walk a WRX unless the WRX has been upgraded; then all bets are off. I would expect the WRX to get 1/2 to a car at launch and then the V8 catches it and walks away as it starts to hook well in 2nd or 3rd gear. 40-80 mph bursts should be owned by the V8 car.
  9. I will be checking back on this, as it is a very interesting thread...And, +1 on the wide open throttle thing, that actually got me too, for a short while.
  10. I think its the carb. The autolite carb is a good carb, but not a true performance carb,
    . I've fiddles w/ Edelbrocks, Carters (same), Rochesters (2Jet), Webers, and Holleys, I like Holley's the best. I have a performer RPM cam, I like it, but I wish I had lower gears than 3.00:1. Maybe even a hairy cam w/ Rhoads lifters.
  11. These heads were worth 40 HP with out porting according to Ford back in the 70's. Now they don't measure up to the new heads out there but they are far better than the stock 289 head. They have larger intake ports and 1.94/1.6 valves. The performer intake is a copy of the Ford cast iron except it has larger ports. I my head I believe it's the carb as its the only thing that makes sense. Although the intake is not optimum, I don't think it would make the engine just nose over like this. The thing runs fine but just feels like your dragging a stump after 4,500 rpm.
    By the way I've been messing with these cars for 35 years and I to have been bitten by the throttle not opening fully. I assure you that has been checked and not the issue.
    If it does turn out to be the carb, I'm going to be tick off as I believed Pony Carbs when they said this was the best-performance carb made for a 289. I guess I needed it rebuilt anyway for the parts shelf. I have rebuilt all the stock parts I took off this car so that someday, due to the rarity of this car, it can be returned to its stock form.
  12. Well, problem solved! Get yourself a good 650 Holley, shelve the stocker, and go smoke the tires!
  13. That graph says it all. The Performer is a dog of an intake. I think your intake and possibly your cam ARE holding you back. Look at how Ford and Shelby made power with a 289. The Edelbrock Performer intake and, to a degree, your cam, don't mesh with the philosophy. The "stump puller" philosophy a lot of media and internet car builders who have never driven a fast car, ever, push on everyone for what they call "street cars" may work for the 1969 351 Windsor in a truck but it doesn't work for a 289.

    You have reasonable heads for a 289. I'd switch to a Performer RPM and something similar to the HiPo 289 cam, or better.
  14. OK, I'm resurrecting this old post with an update. Over the long winter I switched to the Blue Thunder (copy of the ford cobra manifold) intake and a new Quick Fuel 600 dp carb. I also added a Petronics III cast distributor. I wanted to eliminate the stock distributor as a possible problem with something with a better advance curve. Guess what, the thing runs like sh** . After changing the carb back to stock Autolite and it still ran poorly, I found that the new distributor has a problem. It ran fine over 2000 but would not run decent below that. Would not start when hot. So I switched back to the stock distributor with an Ignitor I installed. Now it starts fine. Back to the update on performance. I found about 50 HP with this new combo. Still light from what it should be and I'm now sure it's the cam.
    When it had the Autolite 4100 carb 480 cfm on it. It runs its best as far as drivability. That said I drank the coolaid that Pony carbs was selling when they said this was the best carb for a mild 289 for performance. It definitely was what was holding the performance back. The new intake seems to have done nothing for performance with his carb. The performance was about the same as before but when I put on he new double pumper the engine woke up! Like I said it seems to have found about 50 HP. It's still 50 HP short of what I expected and I am sure that the hydraulic cam I have is a little lazy.

    Now I have a new problem. Engine sputters at low rpm when put under a load. If you accelerate hard I runs fine. It only sputters between 1000-1600 rpm under light acceleration. It seems to be going lean and this is still in the idle circuit on the carb. I have opened up the jets a little at a time until it starts to run poorly and it still has the sputter problem. I reset the jets using a vacuum gauge and set them to the highest vacuum at idle while the engine had a load on it. (AC on and lights on). The engine has about 12.5 in of vacuum and idles fine. Any Ideals? FYI when I switched carbs to the 4100 or to a 750 Holley it still sputters but not nearly as bad. I think I have akimbo of problems here. This problem did not exist with the old manifold and carb installed.
  15. One more comment on the new problem, I did put in new plugs gapped at .04. Could the gap be the problem? What do others do for a plug gap with ingnitor I ignition?
  16. Someone else who knows more about tuning than I will jump in, I'm sure. I would have to use a wide band O2 sensor to set up the carb. I'm not sure how you know that it's lean vs. rich, etc. Reading plugs is not easy or straightforward at all IMO.

    As far as plugs 0.040" is not a bad number. For points you want 0.035". With higher energy ignition you want a wider gap. The gap should be based on the coil and dizzy. Did you replace the coil with a hotter coil when you went to the Pertronix?
  17. this is one reason i dont like double pumper carbs for the street. it sounds like you are getting too much fuel at low speeds. it might not be the accelerator system doing it, it might be the power valve system. that is why i would have gone with the 600 edelbrock carb instead. they are easy to tune, and usually work great out of the box. as to your issue, start by looking for vacuum leaks, fuel leaks, check the size fo the pump jets, the size of the pumps themselves, etc. you might also push the initial timing to between 10 and 14 degrees.
  18. I used to think this same thing before I bought an AED. Holleys metering is all jacked off. the CORRECT non holley double pumper for the combination wont have those issues.

    I would check the plug wires with that low rpm high load stumble. Ive had wires do that and then all of a sudden clear up on top.
  19. I did try a different coil with no change. I will try the wires next. It seems to me that because all the carbs tried seem to have the same issue to a lesser degree. It is most likely somewhere in the ignition that is amplified by something out of whack in the carb. The only thing in the ignition I haven't changed is the wires. Stay tuned and I'll let you know what happens
  20. accell has some decent wires for $40ish. the msd wires are awesome but cost twice as much.