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What makes a 383 Magnum different from a standard 383?

Mocajava

Mocajava

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I have a good running 383 2 barrel with a 727 in my '69 Coronet. Tossing back and forth between a 383 Magnum (or maybe a stroked) vs a 440. The gas mileage for a cruiser with some grunt with a 440 scares me and I have a "standard", running 383 right now to build from. I also have a 440 block that has been cleaned, magged, bored and honed but no rotating assembly as of yet. A full rotating assembly for the 440 or a stroker 383 will cost about 2400 and I am wondering if I can get by cheaper to start with the 383, turn it into a magnum with the rotating assembly I have and be satisfied. Planning on aluminum heads and that will be added to either one so cost is a mute point. Only looking for about 450-500 HP/Torque and a 10.2-5 compression ratio, just a stout street cruiser with enough to play with. THX Professors in advance.
 
A 440 cam, 906 heads for larger valves and ports, and a 4 bbl carb & intake manifold.
 
he probably already has the 906 heads in his 69 Coronet
 
If you are looking for "450-500" out of a 383, fuel mileage should not be on the table. Juz sayin. And you will NOT do that with "factory stuff."
 
If you're worried about fuel mileage you're in the wrong hobby. Unless you fork out some cash for fuel injection, throw mpg out the window. Honestly, you'll be happier with a 440. They're EASY to make the power you're looking for.
 
Burns69RT said:
If you're worried about fuel mileage you're in the wrong hobby. Unless you fork out some cash for fuel injection, throw mpg out the window. Honestly, you'll be happier with a 440. They're EASY to make the power you're looking for.
Click to expand...

Not entirely true but fuel mileage will cost you at least another $3,000. I'm running a 456 (roughly 500hp) stroker with an 850 Demon DP and getting 20 mpg but only because I have a 2013 Viper 6 speed. If you want your cake and want to eat it to you need an overdrive or 2 haha.
 
I am a little surprised gents, I would think cam, pistons, rods and hi performance heads would be a base to kick it to a Magnum. I do understand what you are saying about fuel mileage with the 383 at 450/500 hp/tq, something has to be sacrificed to get that much. To stroke it would be the easiest way to get that hp and tq and still have street manners (idle,vacuum). Then I am back to the full rotating assembly cost for either engine. Kind of narrows it down to what I want as the end game or better yet, what I will be satisfied with. Will have to do more soul searching and creative budgeting to finalize this decision. THX
 
To answer the thread question of what makes a 383 magnum different from a standard 383 is the standard 383 was rated at 315 horsepower while the magnum was rated at 335 hp. From what I've been told is the magnum used the purple shaft cam and had the High performance exhaust manifolds in place of the log manifolds that gave it the extra hp.
 
Standard was 330, Magnum was 335.
 
Depending on the year the 2 barrel might have a cast crank. But in truth just use what you have or want and just a good running 383 4 barrel.

I have used a 750 DP on a 4 speed AMX and got over 15 mpg in highway driving. At a steady cruise the pumps are not being used. That was better then the car got when I bought it.

I have also used a factory 383 2-4 intake with 400 cfm Carters and got over 2 mpg better gas mileage (in town) then the best tweaked 4 barrel setup. It also could be driven cold with its dual electric chokes. No BB Mopar can do that until it has warmed up, without backfiring. Not to mention the looking cool under the hood.
 
Dulcich at Hot Rod made 450bhp using bolt ons on a stock 383ci and a big hydraulic cam. The ones I have seen over 500hp have valve trains and bottom end designed to hit 6.5-7k rpm. One I saw recently was at 620, but it was built to rev, mega expensive and not pump gas compatible.

My lowly 71 383 does pretty well on gas when I keep my foot out of it, along with tall gears, and tall tires... Not happening anymore with the new setup, revs over 6k and dont drive it much on long trips these days. If you keep the revs down on a 383 it will do better mpg than the 440...less cubes obviously and it makes enough torque at low revs to loaf along comfortably at cruise, while reserving the peak HP numbers for higher RPM range than the 440.
 
Sixpactogo said:
To answer the thread question of what makes a 383 magnum different from a standard 383 is the standard 383 was rated at 315 horsepower while the magnum was rated at 335 hp. From what I've been told is the magnum used the purple shaft cam and had the High performance exhaust manifolds in place of the log manifolds that gave it the extra hp.
Click to expand...


the purple shaft cam was not a stock item in the engines....it was aftermarket from Direct connection
 
There's not a dang thing wrong with a 383.
I had a 383 2bbl in a 64 Polara. Used a set of reworked 906 heads, Crowler 460 / 280 duration cam, slightly modified afb four barrel, small tube headers, stock pistons and bottom end with a 456 Dana rear. Had that car in the mid thirteens all day. That engine was indestructible! Believe me I purposely tried to blow it up numerous times!

They have way better cam combos, hotter ignition set ups ect.now days then what they did back then. Good luck with your build...
 
If it were me, I'd freshen up that running 383, call Lunati and have them spec a cam, pickup some aluminum heads sized to boost the compression a bit, find an RPM intake and have fun. Spend a few bucks on an MSD ignition (worth every penny!).

Cast crank, forged crank, blah blah blah - if 40 years of street idiocy hasn't broken that crank yet, it ain't gonna break now.
 
HT413 I have about decided to do just that! Freshen up the 383 with new pistons, good cam, seals, bearings an RPM intake and maybe a set of the Toth heads. Get the CR up to about a 10.1 - 10.5 and have some fun with what I have. I can have the Toth heads done to a stage 2 to be able to swap to the 440 if and when I ever get that built and add that new EFI system that was talked about in the forums. Thanks for the vote of confidence.
 
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