383 Engine questions

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moparmade43

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Hello guys, this is my first post, I have a 1975 Duster with a 416 that I have built for it, just so you know my background. If someone can give me some computer assistance I can get a pic of it on here for ya. But for my first post, I have a question about my C body. It is a 1967 newport custom with the original 383 4 bbl and only 89,000 original miles. I am going to rebuild it this winter, although it runs fine now, and get some more power out of it. I believe, as I know that many other people do as well, that there can be some good power gains out of the 383. I am looking for the area of 425-450 horse for my big cruiser, and equal torque. I will be installing 3.23 gears in the 8 3/4 and a 2300 stall converter i have on the shelf in the 727. I already have 2.5 inch dual exhaust all the way back off the manifolds with dynomax mufflers and will be installing the 1 7/8 TTI headers also. Now my question is, I believe my 383 has the 516 heads, instead of the 915 heads. Can these heads have larger valves installed, with bowl work and port work and work equally well as the more desireable 383 heads, or should I try to find some 906 heads or 915 heads? Also, what aluminum intake and hydraulic cam will work well with the 383? I am somewhat new to big blocks, as I have always had small blocks, and am looking for some ideas. As I plan on using the original rods and crank, please no suggestions about stroker kits or edelbrock heads, as I am wanting to keep the car relatively original looking, minus the headers intake and carb, and not spend a boatload of money like i did in the 416, lol. I appreciate the advice and sorry about the long post

-Will-
 
He he he, post isn't to big. The one parragroh is a little hard to read. (For me that is. No biggie.)

Could you help me out here a second. Just tell me the weight of the car and tire size. (Ex; 235/70/15)

The big block heads of the early years are not really all to different from each other from what I remember. The biggest changes the factory did were to the ports and valve size. Being your looking for about 1.1 horse power per cube, cam choice is alittle tuff considering the 3.23 rear you want to keep.

I think you can use your stock heads with porting.
 
Hey Will, I'm quite up on the 383's and 440's but before I can answer your questions I got a couple of my own. Personally i love a bigblock that revs like a small block. Do you want to make this Newport a sleeper or, judging by your choice of rear gears, a boulivard cruiser. Which ever head you choose make sure that they have hardened valve seats for the unleaded fuel and my best choice for heads are the 906 and 452 with the 452 already coming with hardened seats. You could pocket port the heads using the templates from mopar, which I've done with good success, but before picking the cam, carb and intake we need some more info. In short do you want to rumble or rumble and roar. Check out this link for good BB head info http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/index.html

Terry:burnout:
 
Car weighs, per the service manual, 4200 lbs give or take. Tires currently are 235/70/15's. I bought a set of cragar s/s wheels with tires already on for a great deal from a local mopar friend. However, on the back I'm planning on running 255/70/15s when the rear tires need replaced.

As far as performance, It will do what it will do, as it will primarily be a street cruiser. The car is probably 400 lbs heavier than a charger? So I'm thinking that with the right power and weight transfer, which is what this car does well, I should be able to startle some 5.0 mustangs and late model camaros.

And to answer your question Terry, Yes I want it to be a sleeper, but the thing that this car does best is run down the interstate. It'll run 85 mph all day long and just floats over the expansion joints, which is why I dont want to go much lower than a 3.23 gear. The duster is my stoplight to stoplight ride.

Would something in the .230 at .050 hydraulic flat tappet be too much for 3.23 gears? My main concern in making the power is the 516 heads, I dont know if I can make them flow as well as say a 906 casting, but whatever head I have done, it will have harened seats and 2.08/1.74 valves. Thanks

Will
 
My least concern is the ehads really. With minor port work they will feed 475hp in a 440 easy. So they can make good numbers after they have ben redone properly for performance. But, having owned a '71 383 Newport (and I'm looking for it's replacement. I love that car more than any A or E body I've owned) I can tell you, the 383 is a small engien for that car. What I would suggest is this: Keep the 516 heads, plan on spending around $1200 on getting them "up to snuff". FOr the lower end, the best recipe for torque is stroke. Call Brandon at 440Source, and order up the 3.915 stroke rotating package (after measuring the bore size!!). It will give you a very nice 470, that will pull harder than any 440, weigh less, and look factory. You will be looking for a cam in the 240-245° @ .050 range. Something even like the XE285HL will be a riot, make good horsepower, and more important, big torque from idle up. I ran mine with the 383 factory stock long block, factory intake, Carter AVS, 2bbl manifolds, and duals. But, I ran 3.55, and had a 175hp NOS hit on it. It was the most fun car I've ever owned.
 
The thing is he doesn't want a stroker kit as he stated in the original post.

I would op for the 452 heads myself and do as they have suggested already. I have used a 280H cam and it worked very well with a 2200 converter and is almost a stock replacement for the HP 383 Road Runners.

I like your idea of the little sleeper, OK well BIG sleeper.(C body)
 
Moper, I appreciate the thought on the stroker, but I'm looking to keep the stock bottom end, with the exception of better pistons. But I will agree with you on the C body, mine is the Newport custom, which is the two door model with the high back bucket seats and more fast back roofline than the four door model. It is something completely different than the A and E bodys, and best of all I can haul a load of people in the back seat and 3 kegs of beer in the trunk :cheers:

BJR- the 280H cam, is that a mopar performance cam or Comp? do you know the duration and lift, and can you use the stock steel rockers, or need adjustable rockers? Also, as far as intake goes, for smallblocks I have always loved the combination of torque and horsepower that the Edelbrock Air gap provides. I need the torque to get the big car moving with the 3.23 gears, but the 383 will like to rev too, So I'm thinking edelbrock performer rpm intake as of now. Any ideas, or is there a better street/strip intake for the big block?

Thanks for all your help
 
moparmade43 said:
Car weighs, per the service manual, 4200 lbs give or take. Tires currently are 235/70/15's. I bought a set of cragar s/s wheels with tires already on for a great deal from a local mopar friend. However, on the back I'm planning on running 255/70/15s when the rear tires need replaced.

As far as performance, It will do what it will do, as it will primarily be a street cruiser. The car is probably 400 lbs heavier than a charger? So I'm thinking that with the right power and weight transfer, which is what this car does well, I should be able to startle some 5.0 mustangs and late model camaros.

And to answer your question Terry, Yes I want it to be a sleeper, but the thing that this car does best is run down the interstate. It'll run 85 mph all day long and just floats over the expansion joints, which is why I dont want to go much lower than a 3.23 gear. The duster is my stoplight to stoplight ride.

Would something in the .230 at .050 hydraulic flat tappet be too much for 3.23 gears? My main concern in making the power is the 516 heads, I dont know if I can make them flow as well as say a 906 casting, but whatever head I have done, it will have harened seats and 2.08/1.74 valves. Thanks

Will
Click to expand...

Okay Will you got a bloody heavy car there so this is what I'd do to give her some bottom end grunt. First I'd diffinately go with the bigger valves and ported the heads then I'd change the rear gears to 3.55, better off the line yet you can still run down the interstate without reving the hell out of it. I think your choice of cams is a little mild so I'd suggest one with a spec. of .240 @ .050, it'll be a little lumpier at idle but come on quicker. Next I'd install a edelbrock performer RPM (dual plane) manifold with a 750 Demon vacuum secondary carb. I'd also setup the engine for 10 to 1 compression.
Oh yea, I almost forgot, I ran the 3.55 gears in a charger and roadrunner and always liked them on the highway.

terry
 
moparmade43,
The cam is a comp cams cam and it is .480 lift and 230 @ .050 280 adv. dur., it will work with stock steel rockers. Adjustable rockers are always better, but this means that you have to change the pushrods also. Your thoughts on the intake is right on, and as for the valves and wanting low rpm Tq. and Hp then I would stay with the stock size valves and bowl port the heads and do a good multi angle valve job, as the smaller valves will make the engine respond better and they will make more Tq. and low end Hp than the larger valves, and your not going to be racing this engine or car so the large valves wont help you if any at all. The velocity will be better with the smaller valves and the higher the velocity the more Tq the engine will make, and this is what you said you were after, also it still will be stock and not just appearing. Larger valves generally work better above 6000 rpm's and this is somewhere that your not planning on going. Most of your time will be spent at about 2500-3000 rpms which is highway speeds.
My next choice would be the M-1 dual plane as it works very well too. And there a bit cheaper than the Edlebrock manifolds.
 
Well I went out to the garage and dug out the old 383 engine that came with my Challenger, to see what heads it had on it. I was hoping they were the 452 or 906 heads, but they are the 346 casting. I don't know much about these heads, would they be better than the 516s, or are they smog junk heads?
 
About the only thing that I can add is I would try and find an 1 3/4" primary tube header instead of the 1 7/8". You will end up with a better bottom end than with the bigger tube headers and I would bet you wouldn't or couldn't tell if you lost any top end power.


Chuck
 
Well, the only reason I say 1 7/8 header is that believe it or not, TTI is now making a set of headers for my C body, and they are only offered as 1 7/8, I believe. After messing with hookers and hedmans in the past on E and A bodies, I have come to the conclusion that I will never buy anything but TTI headers again, They fit that well. But, that being said, do you know of any other headers that are 1 3/4 that would fit on a C body?
 
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