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NEWBIE 383 BUILD calling all help

HT413 said:
You say you had the motor rebuilt already. When and how many miles ago? I don't have the experience any of these guys have, but be careful not to fall into the trap of more more more.

Give us (well, those guys, really) more info on exactly what you have - compression ratio, heads, cam, miles, current condition (blowing smoke, etc). Maybe just simple as new pistons, cam, heads? Sure doesn't sound like a complete remachining is necessary.

And I didn't get the feeling from your original post that you were going racing, so what's wrong with a 500 hp stock stroke 383 with some aluminum heads. It'll destroy most things on the road and the motor alone will be over 100lbs lighter than a stock 440.
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I cant really give you the specs because my dad got it done I know it was a stock rebuild and I would love a 500 to 550 hp 383. im not out to go racing I just want a FUN and strong street car. The motor is in good condition maybe 4k since rebuild its just a complete dog.
 
SMITTYS69 said:
I cant really give you the specs because my dad got it done I know it was a stock rebuild and I would love a 500 to 550 hp 383. im not out to go racing I just want a FUN and strong street car. The motor is in good condition maybe 4k since rebuild its just a complete dog.
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what is the axle ratio currently? changing the axle ratio alone will make it feel less "Doggish". 500-550 hp is getting near or over the 5 figure mark.
 
Sorry the 5 figure mark? The gears are stock so im sure they are 3.23 if not worse.
 
I had a budget of 5 to 7 for motor. So I think 500 maybe out of reach.
if i kept my 383 and balanced the rotating assembly good heads and valvetrain with a good size cam, dual plain rpm intake and 800 ish carb. If a guess was given where would I be sitting power wise? Thinking of somewhere around 10.1 compression?
 
69roadr said:
for that budget you will still have a nice build. add the ratio change, and you could smoke the tires effortlessly
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Thats what im going for. I have noticed there are not to many head choices out there and I have read that 440 source ones require machine work or extra parts to work.
 
Before you tear the motor apart, maybe it makes sense to take a head off and measure how far down in the hole the piston is so you can get an idea on compression ratio. Is it dished or domed? Seems like you're thinking on spending all that cash to replace something you're not even 100% sure what it is. Not being critical, just trying to be helpful.

What if you spent your $6000 and it turned out that 383 just had a terrible cam and taaaaallll gears that it couldn't push. Even at 8 to 1 compression, some decent heads and cam, decent rear like a 3.55 or 3.73, the car would move like hell. Maybe it wouldn't make 500hp, but so what, that's just a number to brag about to your buddies.

Heck, even a cam, valve springs, headers and gear change would put a hell of a lot more power to the ground. Though I agree, if you're gonna tear it down and rebuild, it seems to me that it almost is a waste to not stroke it from a $$ to HP consideration.

And I don't mean to come off like a know it all - cuz these guys here have forgotten more than I know. It's just that I've been wrestling with these very thoughts when planning my build and I finally decided enough was enough lol - the treadmill of 'might as well' never ends.
 
HT413 said:
Before you tear the motor apart, maybe it makes sense to take a head off and measure how far down in the hole the piston is so you can get an idea on compression ratio. Is it dished or domed? Seems like you're thinking on spending all that cash to replace something you're not even 100% sure what it is. Not being critical, just trying to be helpful.

What if you spent your $6000 and it turned out that 383 just had a terrible cam and taaaaallll gears that it couldn't push. Even at 8 to 1 compression, some decent heads and cam, decent rear like a 3.55 or 3.73, the car would move like hell. Maybe it wouldn't make 500hp, but so what, that's just a number to brag about to your buddies.

Heck, even a cam, valve springs, headers and gear change would put a hell of a lot more power to the ground. Though I agree, if you're gonna tear it down and rebuild, it seems to me that it almost is a waste to not stroke it from a $$ to HP consideration.

And I don't mean to come off like a know it all - cuz these guys here have forgotten more than I know. It's just that I've been wrestling with these very thoughts when planning my build and I finally decided enough was enough lol - the treadmill of 'might as well' never ends.
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Very true. It does need to be torn down but it was just to re-seal the motor. I do want a bigger cam because its a stock replacement pupple stick. The pistons are flat top I do know that. I was not wanting to replace anything that does not need to be. Just a good set of heads with larger cam and matching valvetrain. Plus the money I save on the engine can go to another needed part of the build.
 
If I was building a strong running 440, for sea level ( or close to ) use, I would start with stock FORGED crank and rods. Flat top 6 pak type pistons, that have about .015" deck clearance when installed. Total Seal rings. Use a .020 " thick head gasket with Eddy heads. This will give you an ideal squish distance of .035" . 915 heads also work good if ported with larger 2.14/1.81 valves. Use a hyd. cam around .500" lift, 284 total duration. Add a Performer RPM intake, 750 to 850 CFM carb and headers. If properly built, assembled and tuned, this combo would be a killer street motor. Stock elec ignition works well if you limit the dist advance to 18 degrees. Run as much initial advance as the engine can take. Like 16 to 20.

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My 451 is built this way except for: 14 cc dome Ross pistons, 509 cam. Holley street Dominator intake, 13 to 1 C/R. Ported 915 heads with larger valves. Holley 780. I run 12.58@109 at 5600 feet. I don't recommend this much C/R below 4000 feet. It has great street manners, with plenty of low end torque. A pleasure to drive with instant throttle response. Good luck!
 
There are several ways to go so I'll give you some very basic guidelines and let you decide.

383's respond well to a mild cam with a 108 degree lobe separation. A .465" / 280 duration on a 108 works very well but likes some gear (3.7 - 4.1). Rumpety-rump idle and low vacuum is the signature of this type of cam. A 700 CFM Holley on a single plane intake works quite well and will have a power band from about 2000 - 6000 RPM. Headers are a must in my opinion. Very fun combo but not good for extensive low speed driving.

For a more true dual purpose engine you would tone the cam down a bit to a 110-112 lobe separation. The result will be less peak torque but more of it throughout the RPM range. Better idle vacuum and stock type carbs will work much better. The car will also run cleaner from idle on up.

For the best of both worlds you will need cubic inches. Build it mild with a similar cam as above and capitalize on the displacement. Think 500 Cad engine. You can also get away with taller gears to preserve freeway cruising.
 
HT413 said:
Before you tear the motor apart, maybe it makes sense to take a head off and measure how far down in the hole the piston is so you can get an idea on compression ratio. Is it dished or domed? Seems like you're thinking on spending all that cash to replace something you're not even 100% sure what it is. Not being critical, just trying to be helpful.

What if you spent your $6000 and it turned out that 383 just had a terrible cam and taaaaallll gears that it couldn't push. Even at 8 to 1 compression, some decent heads and cam, decent rear like a 3.55 or 3.73, the car would move like hell. Maybe it wouldn't make 500hp, but so what, that's just a number to brag about to your buddies.

Heck, even a cam, valve springs, headers and gear change would put a hell of a lot more power to the ground. Though I agree, if you're gonna tear it down and rebuild, it seems to me that it almost is a waste to not stroke it from a $$ to HP consideration.

And I don't mean to come off like a know it all - cuz these guys here have forgotten more than I know. It's just that I've been wrestling with these very thoughts when planning my build and I finally decided enough was enough lol - the treadmill of 'might as well' never ends.
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X2.. If you don't want to take the motor entirely apart.. You at least have to think about taking a head off to get an idea of your piston to deck height.

In the past, lets say 15+ years ago, there wasn't a strong aftermarket for 383's. People were practically giving them away. If the motor had been rebuilt with stock replacement flat tops and the block had not been decked, the pistons could be as much as .080 - .100 in the hole. This is quite common in 70+ 383 blocks. Since you have the original block, I hope that isn't case.

Whatever you chose to do, I would make damn sure you pistons are at tdc, and you'll avoid a lot of issues with compression and the what if's.
 
Last edited:
You may get more power out of your existing 383 by limiting the distributor advance to 16 or 18 degrees. Then start with 18 degrees initial advance at idle, vacumn advance plugged. Then when the dist centrifugal advance kicks in its 18 degrees, you will have 36 total. This makes a big power difference in a big block motor, depending on what you have now. May need a distributor shop to do this.

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Then experiment with your initial advance until it runs the best with no pinging.
 
Garys1969RR said:
You may get more power out of your existing 383 by limiting the distributor advance to 16 or 18 degrees. Then start with 18 degrees initial advance at idle, vacumn advance plugged. Then when the dist centrifugal advance kicks in its 18 degrees, you will have 36 total. This makes a big power difference in a big block motor, depending on what you have now. May need a distributor shop to do this.

- - - Updated - - -

Then experiment with your initial advance until it runs the best with no pinging.
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The main reason im wanting to do all this is after the rebuild it has not ran good at all. Pop threw exhaust or backfire threw carb. Now it just seems like it loads up under normal driving. Im at the end of my patience with this. So I thought add more power since it will be pulled out for a re seal and engine bay paint.
 
What is your timing set at? Its best to iron out all the tuning problems before you rebuild the engine. Take it to a guy in your area who knows Mopars, see if he can diagnose the popping/backfiring noises. Backfire is usually caused by too lean a mixture. Popping may be caused by a broken valve spring, or valve not sealing. Also check the compression with a gauge.
 
My Only problem is im not aware of anyone in north houston that know's mopars. Everyone I have talked to seems to think bb mopars and all old school cars are a thing of the past. If anyone know a person or speed shop please point the way.
 
i,d start with the Mopar Performance speed secrets book. If you read it you should gain some insight into what it takes for your objective.

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City machine in Rosenberg can hook you up. They do a lot of mopars and Damon Kuhn aka Fugly of Diamondback racing engines uses them for machine work. Easy people to deal with
 
SMITTYS69 said:
The main reason im wanting to do all this is after the rebuild it has not ran good at all. Pop threw exhaust or backfire threw carb. Now it just seems like it loads up under normal driving. Im at the end of my patience with this. So I thought add more power since it will be pulled out for a re seal and engine bay paint.
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Sorry to jump in as a newcomer to the forum, but you are making assumptions about the prior build when your problem may be in tuning. What you're describing sounds more to me like a timing issue. If you can't fix it at the distributor, you may need the cam degree'd. Get an expert tune, and you might save yourself a few $k. If everything checks out fine (which I doubt if it's backfiring like that), then change out the rear end as a start since you are planning on doing that anyway.
 
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