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why does my 383 suck? >> now a crack??

I have a dart headed 383. I don't like it. I still say trucks need truck motors. They are heavy and need their engines built for torque. This is why my low compression stock headed 454 will blow the doors off my 383. I have read more than my share about engines but have also built a 10 second camaro, numerous winning dirt track engines and more than my share of truck engines. Until he specifically states what sucks I stand by what I say. Not every engine needs a tunnel ram aftermarket heads and a solid roller. Much of the crap you read on the web is just that, crap. Nearly none applies to trucks. The best suggestion would be to have it tuned on a chassis dyno to correct fuel and timing before making any other change. My bet is it will make a significant improvement for less than the price of a 6 liter swap
 
80' 427 said:
the weights are messed up on that dist. You can see the one on the left has no bushing. Timing will go along way to fixing power. Get a curve kit for your dist and put on one med spring and one light spring. When do you hear this pinging exactly?
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ok, I'll get on that and get the timing set, hopefully tonight.

The pinging is most pronounced at mid to low rpm's when there is any kind of load on (pulling a trailer, going up a hill, headwind at speed, etc) and I give it more than about 1/2 throttle.
 
That is what I figured. What sucks? Low end towing power? Can you limit vac advance?
 
I appreciate all the head info guys and I do plan on trying to get the most out of the engine, but it really sounds like my issues are more fundamental than that so I'm going to try to take care of the basics first I think. Still good info for when I get that far though.

80' 427 said:
They are heavy and need their engines built for torque. This is why my low compression stock headed 454 will blow the doors off my 383.

Until he specifically states what sucks I stand by what I say. Not every engine needs a tunnel ram aftermarket heads and a solid roller.

The best suggestion would be to have it tuned on a chassis dyno to correct fuel and timing before making any other change. My bet is it will make a significant improvement for less than the price of a 6 liter swap
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I had this motor built because I was under the impression that I'd get a lot more torque over my stock 350. Obviously going BB would have been better, but was I misinformed?

"sucks" meaning overall lack of power I expected to have I guess. I can't maintain highway speed. pulling just a small trailer with a wheeler on it feels harder than it should. I've never even used the OD on my NV4500 because I lose speed (gearing is an issue as well, I know). It just feels like an underpowered dog all the time. I'm not trying to spin high rpm's but for every day truck stuff and some light wheeling it's just not getting the job done.

I've never had it on a dyno but I have taken it to a couple of different places to have it "tuned" and it's never run great. Once I get some of the basics figured out with you guys helping I guess that would be the next step.
 
80' 427 said:
How big of a trailer? What gear?
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Saturday I picked up a yard of dirt (according to the garden place about 2200lbs) in my trailer. Cruising along at about 40mph in 4th gear if I gave it any skinny pedal at all it would ping like crazy.
 
I would guess that engine is almost 9 to 1. I need to look up the carb but I am guessing you have lots of things against you.
 
That carb is the fat one so it should be OK if it is working OK. What axle gears? Have you tried unplugging the vac advance and bumping the initial?
 
80' 427 said:
That carb is the fat one so it should be OK if it is working OK. What axle gears? Have you tried unplugging the vac advance and bumping the initial?
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axle gears are 3.73 with 35" tires. Not ideal, but shouldn't be this bad, right?

I have not tried unplugging the vac.
 
80' 427 said:
Really? You think heads and exhaust will fix a lugging problem?
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No man I don't, if you go back and read what I wrote, I said these things make 383 shine, but gotta Figure out the pinging issue first. Two different issues we are dealing with in this thread. You're focused on one and I focused on the other. Nothing you're suggesting is incorrect, for what you're focused on and that's the improper tune, and I think the info I gave isn't incorrect for (AFTER) the tune issue is corrected to make the thing shine like it should.

Don't need a quarrel here between us lets help Ashman out with his truck.
 
Those Gears/tires sure aren't helping. Fix your dist, try unplugging the vac advance and bumping the initial. Look for better geared axles. You have od, you can get away with lots of gear. 6.0s don't lug well either so I don't think you would fix anything.
 
ashman said:
axle gears are 3.73 with 35" tires. Not ideal, but shouldn't be this bad, right?
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'85 in my sig turns 871RPM at 25MPH in 4th(3rd, whatever you want to call it). Based on your specs, in 4th, you are turning 895RPM. And yes, when I don't feel like shifting, I will run it like that, if I'm unloaded and on flat ground.

As long as my timing and fueling is decent, it won't ping.

Based on the bushings missing from the advance weights, I think I'd worry about timing before I worried about anything else.

Also, that picture of the carb shows the bolt being backed out aways. Unfamiliar with those carbs, but assuming that's a gasket-sealing bolt, I'd probably snug it up, and check all the other ones while I was there...
 
dyeager535 said:
'85 in my sig turns 871RPM at 25MPH in 4th(3rd, whatever you want to call it). Based on your specs, in 4th, you are turning 895RPM. And yes, when I don't feel like shifting, I will run it like that, if I'm unloaded and on flat ground.

As long as my timing and fueling is decent, it won't ping.
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yeah, I expect lugging occasionally since my gearing is off, but if the timing, etc is set up correctly I should never ping, right?

Based on the bushings missing from the advance weights, I think I'd worry about timing before I worried about anything else.
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yup, looking like this might be part of my timing issue.

Also, that picture of the carb shows the bolt being backed out aways. Unfamiliar with those carbs, but assuming that's a gasket-sealing bolt, I'd probably snug it up, and check all the other ones while I was there...
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yeah, I noticed that too when I posted the pic. I'll go around it and snug everything back up.

am I hooked up to the wrong vacuum port on the carb? How much of an issue is that?
 
So exactly what kind of pinging are we talking. Like back out of right away for fear of killing innocent bystanders type of pinging?

Or just back out for a second because its mild?

Or keep in it and it goes away pretty quick?
 
blazinzuk said:
So exactly what kind of pinging are we talking. Like back out of right away for fear of killing innocent bystanders type of pinging?

Or just back out for a second because its mild?

Or keep in it and it goes away pretty quick?
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I back out pretty quickly, it's pretty bad. If I do try to keep on it it'll just keep going and get worse.

I did try flooring it once and it did go away for a few seconds then started coming back.
 
Well most motors if you load them up enough (especially without something like an ECM that can pull timing or add fuel) you will get pinging, but under normal circumstances cruising at 60MPH in OD (at what, 1600RPM in your case?) and giving it some throttle shouldn't induce pinging. It's pretty arbitrary, much is going to be based on how the engine is setup. Piston design, head design, compression ratio, fueling, timing, all factors.

As to vacuum, I'm of the mind that unless you need to pass emissions, vacuum advance should always be hooked up to manifold vacuum. If mechanical timing is done right, and vac advance comes off quick, it should improve idle measurably (EFI runs 20*+ at idle because you can) and work under cruise conditions, but as soon as you hit the throttle, it won't be a factor.

I know there are other ways people look at it, but if there is no vacuum, there is no advance (or minimal of course) and the only time you have meaningful vacuum levels are low engine load, when you need and can use the additional advance.
 
The problem is when it is a high emission dist with like 20 of vac advance. Crushing going to light load can get you into detonation because there is still plenty of vac. I like a small can with only 10 deg of advance. Remember a lot of those dist worked with egrs to limit part throttle detonation.
 
I am also of the opinion that any detonation is bad.
 
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