383 SBC combo slower

[Freiburger]

Re: 383 SBC combo slower

You will need the 3000 converter, and it will pick up the MPH when you put it in, with no more gear than you have its taking to long to get up on the motor to make any MPH, so your killing 60 ft and mph.

Think the converter is eating 15 mph?

[Eric68]

Re: 383 SBC combo slower

If it is, there is something "bad wrong."

Actually, the more I think about this, there almost has to be something wrong way beyong changing jets and timing. The MPH is way off what it should run.

[JeffMcKC]

Re: 383 SBC combo slower

I think he has bigger problems than just the convertor, but if its a dog down low it will kill a ton of MPH on low hp high geared cars but not two tons, with a high gear I would over converter it and use the gear multiplication to help out. LOL I would run a compression test and a vacuum gauge to see if the cam is close.

[BACK IN BLACK Z]

Re: 383 SBC combo slower

Just curious where you are shifting at with the 383 vs. the 350. The converter may not be what I would consider optimal, but given the fact that 383s are usually more of a torque monster then a high-winder (I know there are exceptions to that rule).I would think about a 2,400 stall would work fine. You might need to short shift it and see what happens to your speed/e.t. Rear gears should be fine. I am an anti-trick-blow guy so I won't get into the subject of your heads on that combo, but I will say that they might be part of the problem.I was one of the unlucky guys that bought a set of the early flows and they were a train wreck to say the least. alot of folks have good sucess with them, but I like my Darts 10X more. If you go to a bigger cam, watch out for piston/valve issues. IA carb change would be my first step..Johnny

[MadHatcher]

Re: 383 SBC combo slower

Took me awhile to get back with a reply due to W/W ( work & wife)
My best time slip stats: 60 ft 2.026 sec, 330 ft 5.744 sec, 1/8 mile 8.793 sec 1/4 mile 13.686 @ 100.12 mph
650 Speed Demon is jetted stock,70 pri./78 sec. with yellow spring.
Timing set at 15 degrees at 900 rpm. All in by 2,800 rpm at 34 degrees.
As far as the weight of the car, I couldn't tell you. It's a plain jane sport coupe.
MSD box has 6,000 chip and I manual shift it at 5,800-6,000.
Car overpowered the front non-power disc brakes and scooted me thru the beam when I tried to rev it past 2,500 rpm against the converter. Had to leave at 1,500 rpm after that.
I'll tinker with the 650 1st, after that I'll reinstall the 3,000 converter & 750 Speed Demon. I really want this car to deliver when I take it out again this spring. Winter in Ohio sucks.