Is the engine healthy overall now? Do you know the compression ratio, and was it rebuilt? Cranking compression good? How heavy are you? Does your converter really stall 2600? Are you using a spread-bore adapter with the DP4B or is your manifold a Performer 383?

Thats MPH is a little weak for what you have in my opinion, but the carb and intake may be holding you back too.

That cam should be able to get you into the 12s (but maybe not too deep), but it will probably take more converter and a better intake/carb setup to get you there.

the engine is healthy, but gasket leaks, mainly the oil pan and rear main seal, have the bottom of the engine pretty dirty.
the T-quad is used with an adapter to the DP4B, but has been blended and polished [80 grit cartridge roll] to the intake.
the SSH25 only has a 472 [i think] lift, and around a 230 or so duration at 50, which i believe could be improved on, as well as possibly advancing it 4 degrees or so from the straight up position it is now.
cranking compression is within 5lbs on all cylinders at 170lbs. i believe compression ratio is 9:1.
i'm thinking a 3500 [or so] converter would be an improvement. the converter stalls at 2600 according to my stewart-warner stage 1 tach, which may or may not be accurate.
the 13.99-14.10 times were from many years ago before i started playing around with the distributor advance curve and timing. those times were also with my brother aboard.
i can't remember the weight of the car, but from what i recollect, it was around 4000lbs with a full tank of gas, weighed at the local truck stop.
i was going to weigh it this year, but "stuff" got in the way, and i didn't get it done.
i still might be able to do it yet before winter, as the weather looks pretty good [although pretty cool - mid 40's to mid 50's] for some time to come.
bad thing is, there are no tracks within at least a 2-3 hour drive from here to see what improvements [if any] i have or can make.
i have been considering one of those "dragy" devices to use for obtaining a kind of idea what this boat can do.

According to what I can find the SS-H-25 is .485 lift and 238 @ .050. It looks very similar to the DC 484 Purpleshaft, and it probably is what they copied.

170 PSI with that cam tells me your engine is indeed healthy and likely 9:1 CR or higher.

What type of adapter are you using, 4 hole or open? Do you recall how much total timing you had in the distributor when you ran 98 MPH, and did you run on slicks?

If we assume your weight is 4200 lbs with you in the car this is about 323 HP. Thats down somewhere between 50 and 100 HP from what I would expect your setup to be capable of. I would guessa healthy 383 with that cam and good i duction and exhaust should make about 400 HP, but no more than 425 and no less than 375. At 400 HP you would trap about 105-106 MPH. 375 HP would be 103 MPH, and 425 HP would be about 107 MPH. These MPHs won’t put you low 12s but they would put you well into the low 13s and potentially into the mid 12s with the right converter and chassis setup.

I think theres 50 HP somewhere in your current setup that you can unlock. If your timing was way off before (like 26 degrees total or a super slow curve) this may have cost you 20-30 HP. But I would also look closely at your spread-bore adapter also. I’ve never seen anyone really test these on a dyno, but it is the first thing that sticks out to me. If it were my car I would find a cheap ($200 or less) good used carb or borrow one to try. Any 750+ CFM vacuum secondary carb or any 650+ CFM Holley Double Pumper. This will eliminate the TQ and the adapter as variables that could be holding you back. Other potential losses are fuel supply issues (fuel filter after your mech fuel pump only), or if you’re using a drop base air filter that is too close to the choke horn.

No matter what you need a straight threw muffler , Magna flow is what I have, just my 2 cents

There's a lot more in the current combo if you just get a higher stall converter and a Performer RPM or Holley SD intake manifold.

383 definitely needs at least 3200 stall in a B body. Advance the cam +6 to 102, I guarantee that will really wake it up and with stock heads you won't miss much if anything way up top.

The 484 is a perfect cam for a 440 the old .471/.474 purple shaft was a great 383 cam with a stick or some stall.

I don't know what the @ .050 was on the .471/474 cam but it definitely wasn't as big as the .484/ even though the running durations were both 284. The DP4B is better than the Performer but not as good as the newer RPM. I ran a street dominator on mine with a big Race TQ and a set of shaved and ported '67
915 heads. Ran pretty good with a 4 speed.

The best 383 cams (back before everybody went to rollers) I used was either the Crower 271HDP (224/232? ...it's been a "Minute" , lol) for an Automatic...I had mine cut on 108, Or the Ultradyne 231/239 on 108 in +6 for a 4 speed. Both were about .480 I /.500 E

i agree on needing straight through mufflers, plus what was also mentioned, a higher stall converter.
the times quoted was with the stock distributor, having the lazy factory advance, so there is definitely improvements to be made there.
also, the times were run using hard street tires, which had spin at the line which was expected.
i believe my wife's car has finally sold, so that is one object out of the way, however, i just got a phone call from my doc saying i need injections in my back to stave off a future operation, which i will not have happen regardless. i know too many people that have had back surgery that made things MUCH worse for them than before the surgery, so i'll just have to figure out a way around that "fun"..........

FWIW...I've had 2 back surgeries and both went great. One when I was 20 and the other when I was 28. Being older certainly changes things, but just throwing that out there.

My first knee-jerk reaction when I think about something like that is a 3500+ lb car needs way more than 383 cubes on the street.

That's probably cuz the last 383 I did was back in '79... and it was a major under-performer... quite the pooch, unfortunately. I'd hope I would have learned something since then and could actually make one that runs respectively.

Maybe it is time to find a 400 block and make a pump gas HP stroker motor for your car

I agree

It would have to be equipted with some really poor 3" mufflers to affect a 12 second car. Back in the day I had original Flow Masters on my street car with 3" exhaust. One night I removed the exhaust. It weighted 70lbs. Car ran 11.66 @117with exhaust. Then it ran 11.61@117 70lbs lighter back to back. On a side note it had the same converter you do. It also had a very small cam 214/224. Going to a larger cam resulted in no ET decrease but 121 speed. going to a 5300 converter 2 weeks later it went 11.05@122. If your car was mine? Better intake and looser converter first. Maybe borrow a pair of shorter tires. Next would either be head work or a good pair of aluminum heads. If you have a well tuned TQ it should be fine. Even the cam isn't that far off, a liitle small but the cars is heavy and not much gear. The 98 mph seems low. How good is the valve job? It's all in the details. My 360 Challenger is 9.0-1 (runs on 87 octane), ported 2 barrel 360 heads, 220@.050, LD340 intake, 650 holley, TTI headers and 2 1/2" exhaust, dyno max mufflers, 3.55, 2.47 1st gear 4 speed. This is my wifes street car, never meant to be a racecar. In track testing it's gone 12.72@108 with exhaust and air cleaner using 275 BFG drag radial. It's limited by lack of starting line ratio. With a 4.30 and slicks, full exhaust/air cleaner 12.52@110. It weighs 3775 w/ me
Doug

Your car is very well sorted out and hooks up big time. I don't think a normal persons car would do that well.

I ran some old 3" 2 chamber 40 series flowmasters on my cuda back when it ran 11.40s at 117 mph. It ran the same w/ or w/o them. They didn't become a restriction until the car went into the 10s w/ a much rowdier motor.

Not to argue but my experience with Flow masters has been WAY different , Muffler change on a Pont 455 picked up .4 , my old Chevelle LS 6 from 13.20's to 12.70s .

No, I hear you. I've seen some results posted similar to yours. Not sure what the difference is.

I agree straight through is the only way to rock for max performance, and if you run a long muffler with a 20+ inch case they are not nearly as loud as the standard 14 inch deals. But I really don’t think 3 inch Flowmasters are costing him 50 HP at his power level either, maybe 10-20 but I suspect closer to 10.

That said it could depend on the model. I can tell you that a bad set of turbo mufflers, like 3 inch Hush Thrush turbos, can cost you BIG power (like 50+) on a typical 500 HP 440 type setup with alot of overlap and duration. But this is partially because they neck way down inside too.

I honestly don’t think your last trip to the track is a great comparison point. With improper timing and street tires you may find you pick up alot already. But I feel your pain, the closest track to me is also 2-2.5 hours. Theres only one way to know though.

There is a HUGE difference between a set of Dynomax Super Turbo mufflers and a set of Dynomax Ultra Flows even on a 450-500 hp engine. Saw this firsthand w/ my dad's road runner. He was 70 years old at the time and noticed it the first time he drove it w/ the turbo mufflers...he asked me what happened to it? lol

talked to the doc yesterday about the latest MRI i had done last week, and he said there is a lot of things going on in there.
some spinal compression, bad discs, and a LOT of arthritis, among other things.
he suggested trying a couple of steroid shots injected at the hospital while doing an ultrasound [i think that's what he said] so the shots were placed correctly.
i guess i'll try that, so they will schedule that and let me know when it will get done.

"I honestly don’t think your last trip to the track is a great comparison point. With improper timing and street tires you may find you pick up alot already. But I feel your pain, the closest track to me is also 2-2.5 hours. Theres only one way to know though." [GTX MATT]




according to the "butt dyno", working on the factory distributor has made quite an improvement so far, by just being conservative on closing up the weight slots, going with lighter springs, and dialing in more initial timing. still more there with the weight and spring combo, i'm sure.
the cam, in my opinion should be advanced at least 4 degrees.
for now, i'm sticking with the DP4B and the T-quad, as the carb is dialed in very well. that doesn't mean i won't try different metering rods or jets just because, to see if there may be any more improvement there.
i have also considered shorter tires as well, when trying to find improvements, instead of swapping out the 3.91's. back in the day, we did that all the time when playing at the now defunct Nu-Be 1/8th mile track, at times going REAL short when running 2.72 and 2.94 gear sets.
what is the consensus about using something like the "dragy" device to track changes made before going a long distance to a track ?
there are a couple of back roads that one could safely "try out" any changes made without endangering anyone in the public, although traction would be more than likely worse than an unprepped starting line.