I'm in the process of planning out the build on my 1971 Roadrunner. Has numbers matching 383 4 speed motor with all factory parts, minus the carter carb and aluminum radiator(previous owner swap). The question I'm pondering over is should I rebuild the numbers matching 383 motor and 4 speed, or put in a 440 with the additional 4 speed I have so the #'s matching drivetrain won't get worn out or damaged? Would like opinions on the pros and cons to both set ups as well.

I don't see a reason to tuck the #s motor/trans away, unless you know you're gonna do something silly and hurt it bad. If you want a 440, go for it. It doesn't make sense to me to tuck away a B and put an RB in its place. Once it is up and running, there is enough difference in parts and fitment that I doubt the 383 would ever find its way back in. If you like the 383, build it and run it.
Travis..

Depends on a few things

-do you already have a spare 383 to rebuild?

-do you care about MPG?

-is one easier to find locally or are you willing to drive to get one?

-do you already have any spare parts for the low deck, like a dizy or aftermarket intake?

As of right now I just have the factory 383 4 speed in the car, and the additional 4 speed. I have easy access to a lot of mopar parts and can find a 440 down here in south texas pretty easily. Just want some outside opinions of which motor is better and to stick with factory motor or go all out build on another motor.

If you're worried about numbers, keep the 383. If you aren't looking to make a buck or don't care what people think, go with the 440 and hold the 383.
Travis..

Is the #'s 383 in bad shape?

If you are going to have to rebuild it anyway, then sure grab a 440. Might as well.

The 383 will make good power and be easier on gas however, something to consider.

Just depends on what you are looking to do with the car.

That's the hard choice. I'm 18 and of course there's that want to build the baddest car on the road but then there's that other side that wants to make a beautiful restoration piece, since the Roadrunner is a pedigree car. Decisions decisions

Take your time and chose wisely the first go around, no reason to spend $$$ twice on similar things.

Is the 383 worn out?

build a 496 in the 383 block and have the best of both worlds, a bad to the bone motor and a numbers matching car. You could build it sorta like the fast guys with some easy to swap stuff like some better tires and whoop some unsuspecting rustangs

No there is nothing wrong with the factory drivetrain whatsoever. The motor and entire car has 100,017 factory miles on it. The only thing we think may be an issue is possibly a burned valve, but other than that the motor starts up no problem. The car was parked in 1977 and has been garage kept ever since, which is what saved the car (no rust). Origionally sold in california, until second owner brought it to dallas and I'm the third owner down here in san antonio.

Rule # 1.....there's no replacement for displacement. Go big or go home. Dave

I build my cars to drive them like they were intended, thrashed on! When I restore a numbers matching car like my 70 GTX, I keep the original engine and trans in the shop and build another so I wont have to worry about damage. I gaurantee, if you have to sell it, having the car with a built engine in it and including the original will not hurt its resale. It also depends on how fast you want to go, if a 13 second ride is good enough, you can get there with a lightly modified 383, if you want 11's or better, go with the 440. My .02 Lee.

I hate to tell you this, but you shouldn't build either motor. I think you should just sell that Roadrunner to, I don't know, me?

Seriously though..its all personal preference. Some people are purists and belive numbers matching is the way to go. My Chargers, Roadrunner, Coronet R/T are not numbers matching...but its hard for anyone to look at the numbers when I am blowing by them like they are standing still. Decide whats best for you...but if you are on a budget, build the motor you have with some nice yet inexpensive speed goodies, and watch out for the flashing red lights in your rearview mirror!

You said you have access to a lot of Mopar parts. Find a 400 block and build a 451/470/500 and decorate it like the 383. Store your #'s stuff and go have fun with the car!!

383's a great motor & you can stroke them to 426, but I'd save it & build a low deck 400 stroker. Either 451 or 472 & kits are available from many vendors like 440 source, Hughes & muscle motors. Use the RPM intake & thunder carb & headers & paint it to look stock. 400 blocks are cheaper & stronger than a HP 440 block, too. That'll give you the stock appearance w/ tons of power. Good luck whatever your choice is.

I have to side with the (bag it) group. Bag up the # matching parts,
oil and spray them up real good so they don't start to rust,
and put the parts up on a shelf for a later day.
Now, go find a 400 and toss in a 512 kit. Put
on some Stealth heads and paint it up like the
original 383 was looking. When you are giving
rides in it , and boiling the tires in all 4 gears,
and they ask you how a 383 makes this much power.
You just give them the old and tell them
to shut the f*#! up and hang on!!!


After that's out of your system, which some of us
takes years, then put the # matching stuff back
in and give it to your kid. If, it's still in one
piece!

543 cube 440 source kit in an RB block. The price is the same as other size kits. You'll be glad you did. Just sit on the numbers matching stuff & in your spare time you might search for a # matching carb/radiator(which would not be aluminum) for your stash.

A lot of guys, will tell you to go for the bigger motor. Nothing wrong with that. I too am in this position. Build the 383 in the car or spend a bit more and get 57 more cubic inches instantly. What I would really like to know is the general performace gain between the two when you compare a similar performace build up. Cam change, good machine work, decent carb (non stroker) what is the real HP difference...50hp?? Is it worth the extra couple hundred bucks for the block, but need all the little parts you need to purchase because the two motors are slightly different. Lets just say on a basic build up, it might cost you an average of $500 difference between the two. You would think with price difference you could take the extra money and put it into the 383 and make up the difference. Not sure. Bet others have opinions on this. I will say, that most people looking to buy a car would be happy to hear it has a 440 in it. But I wouldn't frown if it had a 383 in it either.

I think I've come down to a decision. I will rebuild the roadrunner to factory appearance and put in a decent cam so it gets plenty of torque and over 400hp. This will be my weekend warrior. Then my 1980 Chevy malibu, that is already hot rodded and fast as hell, will be the car for aftermarket parts and dropping in a big block later after I get tired of my 350. Here's a pic of both the cars.