383 stroked to 431

[curious]

i ve heard of a combination similar to the 451 stroked 400. it is a 383 with 440 crank and rods. it has all the same spec's as the 451 but smaller pistons. i have a 383 so i want to try this. any one know anything abut it?

[69CORONET440]

I too would like the "scoop" on a 431. I have a `69 383 that is going to be a 431" 6bbl edl alum heads 10 to 1 comp. gear drive-4sp-8 3/4 3.55 or 3.91 & maybe a N.O.S. Cheater system :^) over the summer hope to get most all the parts and over the winter get it together for an early spring shake down-$$$$ willing! so far so good-

[72Challenger]

Never heard of making a 451 by offset grinding a 440 crank in a 383. Suppose it could be done, but the normal way is to use a stock 440 crank in a 400 block. See our own Mopar Chat member's definitive article at:

http://www.phoenix.net/~atc347/451/

[Dr. Mopar]

Originally posted by curious
i ve heard of a combination similar to the 451 stroked 400. it is a 383 with 440 crank and rods. it has all the same spec's as the 451 but smaller pistons. i have a 383 so i want to try this. any one know anything abut it?

I have performance shop and build 451 and 431 motors quite often. If you are interested contact me at Tothperformance@csonline.net

[451boy]

A 440 crank with mains turned to 383 size should drop right into a 383 block. Use 440 rods (or aftermarket) and custom pistons and you have a 431. A steel 440 crank should have its counterweights turned to 7.250 diameter. This will provide clearance and will drop the weight down so it will balance. Bobweight will be right at 2400 grams once it is turned like this. Not sure what A70's problem was, maybe he was using a cast crank?

Not very many pistons for the 431 combo since it isn't very popular. Ross has a piston last I heard for $550 or so. If you're going to race it I'd spend the money and get the Manley rods. $550 and they are yours. Then you can run a 0.990 pin in the piston and save even more weight. Lots of guys run stock 440 rods, but I don't bother with them anymore. Brand new rods are cheap and are a ton stronger. You really want the 440 rod in there and not the 383 rod. The longer the rod you can put in the motor the better she'll run. It might not be a huge difference, but you're buying parts anyway so might as well buy the better combo.

[JANDJ]

I HAVE A 431 IN MY 70 RDRNR.IT IS AN AWESOME MOTOR! I DID IT BECAUSE OF THE SAME REASON YOU DID, I HAD A COUPLE OF 383S THAT RAN SO I NEW THEY WERE BETTER THAN BUYING A BLOCK FROM A STRANGER.BY ALL STANDARDS MY 431 IT PRETTY MILD AND IT HAS PROPELLED MY CAR TO 10.86 AT 123! I HAVE THE CRYSLER CRANK WITH EAGLE RODS,SMALL ULTRADYNE SOLID(260@.50 586),TWELVE TO ONE COMP.,ROSS FLAT TOPS,INDY SRS,MI WITH 950 HP,I SAY GO FOR IT!!!!

[curious]

whats 950hp?-horse power? if so wow if not is 950 mean 950 high performance?

[JANDJ]

HOLLEY 950 HP CARB

[curious]

how much did the indys set you back? what features do the srs's have. are they hard to install? i ve been strongly caautioned against them due to fabrication needs and expense. every body says unless your looking for more than 600 hp go with edelbrock (simpler chaeper) what gives? whats with external oiling or whatever?

[JANDJ]

WHEN I BOUGHT THE INDYS THE EDELBROCKS WERE STILL A DREAM. I PAYED MORE MONEY BUT I FEEL I GOT A BETTER HEAD IN THE LONG RUN. IF THE E BROCKS FLOW WHAT THEY SAY THEY ARE A GOOD SET OF HEADS BUT I DONT THINK THEY HAVE ANY WHERE TO GO I CAN PORT THE INDYS TO MAX WEDGE PORT SIZE AND THE ALSO HAVE A 64 CC LARGER INTAKE RUNNER , THEY CAN FLOW 350 EASY WHERE AS I DONT THINK THE EBROCKS ARE CAPABLE OF THAT BUT YES I PAYED A LOT MORE. THE EXTERNAL OILING IS A FAR BETTER WAY TO GET OIL TO THE HEADS,SO MUCH SO I RESTRICTED MINE. I HAD MINE CUT TO 65 CC CHAMBERS GASKET MATCHED AND BOWL BLENDED WITH 2.19 AND 1.81 VALVES WITH TITANIUM RETAINERS FULLY ASSEMBLED WITH THE INSALATION KIT HEAD BOLTS, VALLEY PAN COVER (WHICH IS WAY BETTER THAN THE BATHTUB) AND I AM SURE I AM FORGETING SOMETHING BUT IT WAS $2800