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Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2951812
08/08/21 06:12 PM
08/08/21 06:12 PM
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fast68plymouth Offline
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Unparkerized cam....... probably MP.

The MP lobes are smooth and stable, which = more rpm before the lifters get upset.

I would absolutely expect the MP cam to rev higher before the valvetrain got unhappy than the XE275HL.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Made it to the track, a little disappointed. [Re: fast68plymouth] #2951823
08/08/21 07:03 PM
08/08/21 07:03 PM
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Arizona, USA
gsmopar Offline
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They let you run in shorts?

Re: Made it to the track, a little disappointed. [Re: fast68plymouth] #2951839
08/08/21 08:06 PM
08/08/21 08:06 PM
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Ontario, Canada
500ciBee Offline OP
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Originally Posted by fast68plymouth
Unparkerized cam....... probably MP.

The MP lobes are smooth and stable, which = more rpm before the lifters get upset.

I would absolutely expect the MP cam to rev higher before the valvetrain got unhappy than the XE275HL.

That makes sense.
Thanks!


1970 Super Bee prostreet. 383, SMR 727, Dana 60 4:88. Building a 512 low deck.
Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2951865
08/08/21 08:48 PM
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Originally Posted by 500ciBee
Originally Posted by bee1971
[quote=500ciBee]

Ok thanks! That answers that. More incentive to start collecting parts for the stroker.
iagree
That is what I would do, 400 stroker motor rule up devil boogie


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2951878
08/08/21 09:11 PM
08/08/21 09:11 PM
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Prospect, PA
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One sure fire way to turn a 383 into a turd, install a fast rate hydraulic cam. Like PRH said, the lifters will not allow a 383 spin high enough to make use of the cam size. I agree with doing a swap to a solid lifter on the cam to simply check. But the valve springs need to be right too. My 383 is similar to yours. MP 280 cam. It will spin 7000 rpm (not that It should, but it is so much fun). If I had to shift it at 5500, it would be totally neutered..

Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2951881
08/08/21 09:28 PM
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Originally Posted by 500ciBee
My expectations weren't very high. Just thought by improving the 60" by a few tenths would lead to a few more tenths off at the end.
4.88 gears
33" tire
3500 stall
Don't know what the weight is. Tubbed with a cage. Not much interior.
Shifted at 5500

https://youtu.be/8xeiaGZZCdc


You do seem to be going through the finish around what you shift at. But 4.88 gears, even with 33" tall tires, seems like a lot for a "stockish" 383.

Going to a bigger carb (750 to 850) to improve street drivability seems like the wrong direction to go.

Tuning the carb can sometimes provide surprising results. But it takes patience, tuning parts (jets, squirters, pump cams) and an understanding of how they interact. There are some good, old Holley tuning books out there that I learned a lot from.

Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2951922
08/09/21 12:54 AM
08/09/21 12:54 AM
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If it was my car I'd put a SFT cam in there somewhere along the lines of a Mopar 0.528. I don't think I'd actually buy a Mopar cam anymore since they are super expensive and the the QC is spotty but just something in that range. With 4.88 gears you might want even more cam than the 528 but it is only 383 cubes and you mentioned that you wanted some bottom end torque. Actually I'm having a hard time figuring out your combination since you have a dual plane intake and 4.88 gears. Those two things usually don't work well with each other but I suppose the 33 inch tire kind of mellows out the steep gears.

I'm not positive what the issue is with your combo but it could very well be that the hyd lifters are heading home just when the rest of the combination is getting ready to party. All it takes is one part in the engine to quit early and the whole combo slows down. Of course you could also have some other issue such as fuel delivery, ignition, etc. Lots of things can kill the power.

Re: Made it to the track, a little disappointed. [Re: AndyF] #2951979
08/09/21 10:06 AM
08/09/21 10:06 AM
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Quote
you could also have some other issue such as fuel delivery, ignition, etc. Lots of things can kill the power.


Since the ignition and fuel delivery were good for 13.0@109 before, it’s unlikely they’re the problem now.
And that was with the cam going away.

109 was enough speed to run well under 12.50.
A converter swap alone would have had the OP reaching the performance goals, although it wouldn’t have done much for the drivability.

Since the OP states the lift on the old cam was close to the new cam, the old cam was probably a MP509 cam........ which would def make more HP up top than the XE275HL(248@.050 vs 231@.050).

The Moroso chart shows difference in speed between 109mph vs 101mph, at around 3600lbs to be roughly 85hp.
The question at this point is, how much of that speed gap would be made up by just having the valvetrain be stable for the full 1/4 mile run?


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Made it to the track, a little disappointed. [Re: fast68plymouth] #2952008
08/09/21 11:16 AM
08/09/21 11:16 AM
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Couple of thoughts/questions

1) Something is off with your combo - you are not trapping much more than what a basically stock 383 should trap in a stock weight B body, with stock converter, 4.10 or less gear, etc. That would be a good running stock 383, but nonetheless its been done. With headers and good exhaust a stock cam would make the same MPH. You have more cam, a better intake system, and what must be a healthy short block with 175+ PSI. Sounds like this is not a low comp 383 either.

2) You may have too much converter - didn’t look like you came up on the converter much on the line but it looks like you’re only dropping to about 4500 on the shifts, I would think it should be coming down a bit more than that from only a 5500 RPM shift point (it looked like you pulled second at more like 5200). Are you sure the converter isn’t looser than 3500?

3) I wouldn’t condemn the cam yet, but if you want to go back to what you had if you had the 509 Mopar cam the Racer Brown SS-H-44 is supposed to be very close

4) Did you degree the cam? Did you make any change to the fuel system? Did you change the pushrods, or check your lifter pre-load? Your pushrods may be too short and causing additional issues.

Last edited by GTX MATT; 08/09/21 11:27 AM.

Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
Re: Made it to the track, a little disappointed. [Re: fast68plymouth] #2952009
08/09/21 11:18 AM
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I’m with Fast, cam and single plane intake. I had the 509 in my 383 and ran 117 mph but about 400 pounds lighter stock vert and 4.88s

Last edited by cudaman1969; 08/09/21 11:20 AM.
Re: Made it to the track, a little disappointed. [Re: cudaman1969] #2952041
08/09/21 01:18 PM
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I know this isn't that same but, I have a comp cams xe275hl in my stocker, 69 340 daily driver that I do randomly take to the track for fun as I'm a performance guy. Mine will not rev either, it's the cam. I've changed springs and shimmed until my hair falls out diff pre load etc etc and done everything you can try twice. 5,700 it's over with. Runs 12s but sucks. If I put my solid st21 in the exact combo it will rev up. . The xe275 is a killer daily slash low rpm deal. You fight the same issue I have as a 340 has zero torque. The cam works really good until it don't right where a 340 is wanting to go. Change cam to a solid and don't look back. Just my 3yr combo experience with the same cam.

Re: Made it to the track, a little disappointed. [Re: AndyF] #2952044
08/09/21 01:35 PM
08/09/21 01:35 PM
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Ontario, Canada
500ciBee Offline OP
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I'll give a bit of a background on the car. My dad bought the car about 16 years ago pretty much the way it is. It was built to handle big power and the previous owner had planned to put a stout stroker in it. That never happened and he sold the car with the 383.I believe it was put together with spare parts that he had. For a variety of reasons my dad didn't get around to building another engine. I have the car now and have a 400 block to work with. I swapped out the cam because it had a rounded off lobe. Thought the new cam would help the lowend which it did but didn't expect the topend to drop off so much. Eventually the car will run as fast as it looks. Right now its all show and no go. grin


1970 Super Bee prostreet. 383, SMR 727, Dana 60 4:88. Building a 512 low deck.
Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2952073
08/09/21 03:03 PM
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I agree with the above posts by Fast and Bee1971.

I had an XE cam in my 470. I'd heard people bash the XE line for years but, was one of the lucky ones that could get one to rev past 5500rpm or so. The car pulled clean to 6200 without issue. Put a set of ported heads on my car with different springs. Picked up around 40-50cfm in head flow and the car went no faster. With the new springs, the lifters were not happy starting around 5400-5500.

I did similar to what most have tried with these cams and thought I had an issue but, it's the cam. I've never seen anything like it in the past. When people say "hit the wall" or "it's done at x rpm", it's no lie with the XE cams. My car sounded like it had a rev limiter on it, it truly would not rev past 5500-5700 rpm. Can't remember where I saw it but, there was an article I found where they dyno'd one of the XE cams and ran into similar issues. Tried a whole bunch of different things with little success. It was interesting to see the curve when the cam get's unhappy.

Called Dwayne (Fast) earlier this year and had a SFT ground.

The XE cams, for the advertised power range, really work well but, they are done when they say they're done.

Re: Made it to the track, a little disappointed. [Re: parksr5] #2952436
08/10/21 12:38 PM
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with a stock bottom end 383 in my charger, stock 906 heads including springs, DP4B intake, 850 T-quad carb, SSH-25 hydraulic cam installed straight up, 15% initial, 36% total timing, B&M hole shot converter 2600rpm, home brewed shift kit, 3.91 gear, 27" street tires, and 4000lbs plus, shifting at 6000, my charger runs 13.95-14.15 depending on the air.
just a comparison for the OP to consider for tuning upgrades.
beer

Re: Made it to the track, a little disappointed. [Re: fast68plymouth] #2952440
08/10/21 12:50 PM
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Originally Posted by fast68plymouth
Quote
you could also have some other issue such as fuel delivery, ignition, etc. Lots of things can kill the power.


Since the ignition and fuel delivery were good for 13.0@109 before, it’s unlikely they’re the problem now.
And that was with the cam going away.

109 was enough speed to run well under 12.50.
A converter swap alone would have had the OP reaching the performance goals, although it wouldn’t have done much for the drivability.

Since the OP states the lift on the old cam was close to the new cam, the old cam was probably a MP509 cam........ which would def make more HP up top than the XE275HL(248@.050 vs 231@.050).

The Moroso chart shows difference in speed between 109mph vs 101mph, at around 3600lbs to be roughly 85hp.
The question at this point is, how much of that speed gap would be made up by just having the valvetrain be stable for the full 1/4 mile run?


But he hasn't had the car to the track in 8 years so lots of things could've changed. Fuel filters could be plugged, parts can fail, etc. The performance isn't there and it could very well be the fast rate cam blowing away the lifters but it could also be something simple like a bad coil wire.

Last edited by AndyF; 08/10/21 12:52 PM.
Re: Made it to the track, a little disappointed. [Re: AndyF] #2952467
08/10/21 01:45 PM
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Good point about the 8 year interval.

An ignition tester should be able to verify that system is up to snuff, along with flow testing the fuel system(electric pump) to make sure it’s keeping up.

At this point, it makes sense to perform those tests.
But the motor not wanting to get past 55-5700 or so is pretty much par for the course with those cams.
You’d basically be verifying you don’t also have another issue to contend with.

Frankly....... the drop in performance with the new cam/intake/carb is pretty ugly......imo.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Made it to the track, a little disappointed. [Re: fast68plymouth] #2952489
08/10/21 03:05 PM
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I would hate to see a guy go to the effort of changing the cam when it was just something simple like a tank of bad gas or the gas tank vent is clogged. So I guess my advice is to verify all of the simple dumb stuff before tearing the engine apart.

I might be overly sensitive to the issue since lately I've had a bunch of customers come in for "EFI problems" and none of them turned out to be EFI problems. One guy had a broken valve spring, one guy had a loose connection on his coil wire, one guy had old gas in the tank, etc. In all cases the engines ran poorly and since the cars had EFI they just assumed that the "EFI system was acting up". And the last guy that came over to have me look at his EFI system had the timing retarded by 12 degrees. So not an EFI problem after all, just hadn't ever checked the timing.

Last edited by AndyF; 08/10/21 03:28 PM.
Re: Made it to the track, a little disappointed. [Re: AndyF] #2952588
08/10/21 07:22 PM
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Ontario, Canada
500ciBee Offline OP
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Thanks for the input everyone! I'm certainly leaning towards the cam being the culprit. I've got a MSD 6AL ignition box (no rev limiter chip in it) with a MSD Pro Billet distributor. I have the fuel pressure regulator set at 6.5psi. It seems to bump up to 7.5 when I launch. The gauge is next to my right knee in the video. I used fresh 94 octane gas. The plug wires are old but I checked them out this spring and the all tested within spec.
I'm not trying to ring out every last tenth in the car. Probably won't be back at the track until next year. I won't change the cam. It drives around town well now and can do burnouts with a 21.5" wide tire. grin Couldn't do that before. Was a little disappointed because the car seemed faster. Hopefully someone else can benefit from this thread.


1970 Super Bee prostreet. 383, SMR 727, Dana 60 4:88. Building a 512 low deck.
Re: Made it to the track, a little disappointed. [Re: 500ciBee] #2952626
08/10/21 08:34 PM
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Thinking a little more on those lifters. Is there a possibility of them pumping up and lifting a valve or two off the seat at 5500. Reason being my 383 had the 509 with crane anti pump ups and I set them at zero lash. 4.88 gears 29,5 tire 117 mph, 11.65 you can figure the rpm out. Easily would have went faster with a high stall converter. (Had a Street Hemi vert)
Just looked at the Wallace calculater 6887 rpm. Never needed a tach, shifted by feel. It screamed they all thought I had a small block Chevy, were they supprised.

Last edited by cudaman1969; 08/10/21 08:47 PM.
Re: Made it to the track, a little disappointed. [Re: cudaman1969] #2952665
08/10/21 10:11 PM
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500 - I enjoy the camshaft around town , cruising and stoplight to stoplight

Idles awesome , great vacuum , torque off idle and just stabbing the go pedal at say 30mph and having the car sideways with an automatic
Will destroy the tires off idle just stabbing the pedal

Fun , YES

I went as far as taping a vacuum gauge to the windshield , checking fuel pressure
Tried every Mopar ignition module blah blah

Different carbs - Pulling plugs - Jetting

Timing - Distributors

Most on this thread commenting , helped me chase something in reality that wasn’t fuel or ignition related

I just couldn’t accept the fact a 383/432 Stroker was dead by 5400 RPMs - Again like a rev limiter honestly


1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
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