stock 383 mopar

[novadude]

How would a 650 cfm Demon make less power than a 650 cfm AFB if Both carbs have been tuned to deliver the appropriate mixture? I can't see how throwing more parts at this is the right way to "fix" it?

[user-612937456]

Just ordered parts. It was a 750 demon carb BTW after he brought me the box. Edelbrock performer 2186,
Cam is 107 LSA
Duration @ .006 279-296
Duration @ .050 227-241
Lift .486-.473
ICL 102

My understanding is the exhaust valve is undersized a little in these early 383's so the reasoning for the long exhaust lobe.
Discussed two different options on the camshaft and the customer wanted the loopier idle.

This is going to be a guy you arent going to make happy, proceed at your own risk

I don't deal with PITA customers I usually weed them out before I turn a bolt lol. But this is a returning customer for the third time no problem anticipated

Next question is exhaust; I have been advised to use some 440 Magnum C body exhaust Manifolds they are supposed to be much better than the logs that are bolted up now.

Does anyone have an opinion on if there is a significant enough improvement to justify changing them?

[statsystems]

Just ordered parts. It was a 750 demon carb BTW after he brought me the box. Edelbrock performer 2186,
Cam is 107 LSA
Duration @ .006 279-296
Duration @ .050 227-241
Lift .486-.473
ICL 102

My understanding is the exhaust valve is undersized a little in these early 383's so the reasoning for the long exhaust lobe.
Discussed two different options on the camshaft and the customer wanted the loopier idle.

This is going to be a guy you arent going to make happy, proceed at your own risk

I don't deal with PITA customers I usually weed them out before I turn a bolt lol. But this is a returning customer for the third time no problem anticipated

Next question is exhaust; I have been advised to use some 440 Magnum C body exhaust Manifolds they are supposed to be much better than the logs that are bolted up now.

Does anyone have an opinion on if there is a significant enough improvement to justify changing them?

Whose cam is that? I can't thing of a single reason to run that much exhaust timing with a 107 LSA. Just seems wrong to me.

[pdq67]

^^^^^^^^^^^^^^^

Unless it is a CC, "Thumper", cam???

pdq67

[echosixmike]

In my limited experience, all the cast manifolds perform basically similar, with the exception of the max wedge stuff. If he wants some noise, perhaps sell him some headers? The 66 383 should be 516 heads, which normally had 1.6 exhaust valves, and were generally "meh" for performance. The Eddie Performer is nice just from the standpoint of losing weight. S/F....Ken M

[PackardV8]

Classic case of mission creep.

Have Daytona Carb rebuild the Carter. Have a distributor shop rebuild his distributor. Put it back stock and leave well enough alone.

[Dana57]

The base Edelbrock performer Intake with a good rebuilt Theroquad will provide better drivability then the stock set up and also better top end power!
For any low deck of high deck Mopar with stock heads and shifting at 5500 it does not get any better then this!

This gets my vote. I think TQ's are the most underrated carbs.

X3

[user-612937456]

Whose cam is that? I can't thing of a single reason to run that much exhaust timing with a 107 LSA. Just seems wrong to me.

I'll talk to David today about this spec'in a couple different options on the camshaft for me. I brought up the thumpr cam because the customer wanted the usability of the low RPMs but he wanted the engine to sound a lil more radical. This seemed like a good compromise the intake lobe was spot on for what we all wanted out of the engine although David didn't like the exhaust side being so long. But after David work the numbers up we were only sacrificing about 20 horsepower so considering this is not competition Racing Engine the customer was willing to make the sacrifice to get the idle sound he wanted.

[pdq67]

Damn, I hit it!!

A, "Thumper" cam!

He, he!!

pdq67

[Geoff2]

Yeah, the 'Thumper cam', misnamed, should be the 'Crapper cam'......Those cams are for image, not performance.

The extra exh duration will kill off what little low end tq the 383 has, but it will 'sound' great. Sadly, performance will not match the sound......

[mag2555]

That small Exh valve in those 516 heads demands headers if you or your customer demands to see HP numbers peak above 4500!
In fact I would sooner run Headers then a Cam with more Exh duration, I would take full advantage of that big lifter and have comp Cams or someone grind you up a Exh lobe with at least .030" more lift then your running on the Intake side and with a faster opening ramp!

[user-612937456]

That small Exh valve in those 516 heads demands headers if you or your customer demands to see HP numbers peak above 4500!
In fact I would sooner run Headers then a Cam with more Exh duration, I would take full advantage of that big lifter and have comp Cams or someone grind you up a Exh lobe with at least .030" more lift then your running on the Intake side and with a faster opening ramp!

but isn't this engines more limited on the amount of lift. I'm not sure where to stop at but I know you don't want to go crazy on the lift with stock pistons? How much over .500 would you feel safe?

[Carnut1]

7feb04bb25fb0dae22051ab69a3fe4eb.jpg

Long Island east end summer house. I was about 15 years old. Hanging around older city kids in a Newport monolith. 383, 727, dead gears, peg leg, and I believe a 2 barrel. Loaded with dumb teenagers probably weighed 5000 lbs. Totally stock borrowed from my friend's Mom.
Would burn a single in first to about 70 mph and upshift 2nd to 3rd at about 100 mph. Instantly addicted to the high rpm sound. For this project I would rebuild the worn out parts, headers and nice dual exhaust, gears and a posi. Done. Those heads will need upgraded springs with that cam and I am sure will also need guides and a valve job. Thanks, Charlie

[cv67]

wonder if steve dulcich lurks here sure he'd know the perfect setup


love those barges and the sound of a bbm winding up
no say on the thumpr and demon hope hes happy he has to understand it will never feel the same as teh carter

remember as a teen a boss I had rebuilding tquads al the time. Big goofy looking piece but they sure worked wel
he had a pile literally 3 f high and 5 ft diameter of holleys...knew back then I shoulda kept them all went to the junkman.

[cpmotors]

FWIW- 1966 Coronet engine I did. Could use a converter but he still has the stock unit, 3.23 gear.
516 Heads, Howards HR & Morel Lifters, Performer intake with 650cfm Edelbrock.
Test: CP Motorworks chrysler 3837
STP J-607 Corrected Power
Range: 3100 RPM - 5500 RPM

EngSpd: 4300 RPM
STPPwr: 320.6 CHp
STPTrq: 393.5 Clb-ft
AFR : 13.4 Ratio
CoolOt: 164 deg F
Oil_P : 69.4 0-150p
OilOut: 83 deg F
AirSum: 425 SCFM
375hp @ 5500, 409lbs @ 3800 with 36 degrees thru B body manifolds with 2.5" pipes

https://www.youtube.com/watch?v=oVC4Cwv ... 2&index=13