440 swap or build the 383?

[Scotty76]

Greeetings. I bought a 65 Polara last fall and have been addressing a few things over the winter, it's a fantastic running solid car. I'm not new to working on cars/motorcycles but I am brand new to Mopars, this is the first classic one i've owned, I do have a 91 Jeep and a Ram daily driver. The motor is a 383/4 barrel, it's original to the car. According to what I've found that's a 10:1 motor? I really like the car and the thing runs terrific, no smoke no bad noises, a few minor leaks that I've addressed. However, it is a little bit of a pooch. This winter I was considering the comp replacement for the Mopar Purple 484 cam, 440 source heads, Performer RPM intake and a decent carb. The car will likely see the track 1 time if at all. Current rear is a 2.76 but I'm about to put a sure-grip 3.55 in it. So, I got to thinking - would it be a better idea to do these same upgrades to a 440 and stab that in? I understand there is potentially fab work and the left motor mount needs to be addressed but there are easy solutions for that. I have done engine swaps before so not too concerned there. My question is if I end up with a low comp motorhome or truck 440, am I just chasing my tail? If I can confirm it's from a passenger car 440, what compression ratio where those available with?

So, basically, should I stick with the 10:1 383 or is any 440 likely going to be a better option? Thanks!

 

[polara71]

Stroke the 383.

 

[CBODY67]

The 383 4bbl you have is a 10.0CR motor, just as all 4bbls were back then. It does have the 2bbl cam, though. 252 degrees with .390 lift. The '66 B/RB engined cars got the then-new 256/260 .425 lift cam, with the same heads and such.

A factory 383 4bbl car would have had the 3.23 as standard, 2.76 optional. Which means somebody ordered it that way. Obviously gas mileage might have been an issue back then? But our '66 Newport has a natural cruising speed of 75-90mph, which is right on the front side and at the peak of the torque curve with the 2.76 axle and H78-14 tires. It has HD shocks, too.

Many will recommend building the 440, no matter what. Personally, I like 383s and would recommend using the Summit cam which is the same as the Lunati version of the 383 HP cam. At least one poster in here has it and likes it in his '68 Fury 383 4bbl car. Add the Edelbrock Performer 383 intake and an AVS2 carb of 600+cfm. Some thick-wall headers with a good undercar exhaust system (TTI is a favorite one in here).

You can work the existing heads, adding 1.74" exhaust valves or get new aluminum ones. Your choice. For pistons, Mahle has some modern "mm" ring width pistons. A stroker rotating assy is always an option, for about 452cid or so. So you get the cubes without any issues with the taller 440 block.

Ignition system? When Chrysler was still doing the Mopar Performance electronic ignition conversion kit, it was the best way to get OEM-quality factory parts at a decent price. Included the factory wiring harnesses, so plug-n-play. Now that they are licensing it, not so good. The DUI conversion kits (using a GM HEI module) have gotten good reviews here and elsewhere. Pertronix is another choice. Progression Ignition in Florida has a new distributor which can be programmed via a smartphone, as to distributor and vac advance curves, plus an anti-theft feature. Kind of pricey, though, but neat.

Enjoy!
CBODY67

 

[CBODY67]

440 compression ratios? Earlier ones were 10.5CR. 1971 went down a bit, with 1972+ being 8.2 rated compression ratio. So plan on needing higher compression pistons, which is where Mahle might come in again. If you are going to upsize the cam, higher compression pistons will be needed too. PROVIDED you can get fuel in your area to run the 10.0CR situation, at a price you can afford.

CBODY67

 

[HOT FURY]

Save the original 383 then pick up a 400 to stroke if you want to go with a whole new motor. Stronger block than either the 383 or 440. Otherwise if your rotating assembly is good in the one you have put some better heads, intake, cam, exhaust, ignition, rear end gears, etc on your existing shortblock and run with it. You'll be amazed how much you can wake up your stock 383.

I'm currently in the process of building a stroked 400 and will pull my 383 like I said above. My rotating assembly and some other parts just arrived last week from 440 source!

 

[LocuMob]

I put a 440 in my '66, two so far actually. First one was rebuilt but they didn't break in the cam, and I got a season and change before the cam was flat. Stabbed a .484 Purple shaft in, 440 source heads straight out of the box, Eddy Performer intake, and shortly after a rebuilt 727 manual valve body with a 2800 stall convertor. Car already had 3.55's out back. It was pretty good for a basic rebuilt engine. Found a ton of oil on the 5 and 7 plugs, so I swapped new rings and Con rod bearings and got another season before the other side threw a rod. Went to a '77 low compression 440 with 452 heads, another .484 purple shaft went in, and I installed tti headers and 3" pipes. It's not as snappy, but still fun enough for me. Those engines replaced the stock 383-2 that was a weezy tired old mill, the difference was night and day with either 440.

But I'm going to build either a 383 or 400 stroker engine for another car, using mostly the same parts you mentioned, with a larger cam obviously. All depends on if the 400 I know about is still available. If not, I have plenty of 383's laying around. My goal is a sleeper-ish look.

 

[HOT FURY]

I put a 440 in my '66, two so far actually. First one was rebuilt but they didn't break in the can and I got a season and change before the can was flat. Stabbed a .484 Purple shaft in, 440 source heads straight out of the box, Eddy Performer intake, and shortly after a rebuilt 727 manual valve body with a 2800 stall convertor. Car already had 3.55's out back. It was pretty good for a basic rebuilt engine. Found a ton of oil on the 5 and 7 plugs, so I swapped new rings and Con rod bearings and got another season before the other side threw a rod. Went to a '77 low compression 440 with 452 heads, another .484 purple shaft went in, and I installed tti headers and 3" pipes. It's not as snappy, but still fun enough for me. Those engines replaced the stock 383-2 that was a weezy tired old mill, the difference was night and day with either 440.

But I'm going to build either a 383 or 400 stroker engine for another car, using mostly the same parts you mentioned, with a larger cam obviously. All depends on if the 400 I know about is still available. If not, I have plenty of 383's laying around. My goal is a sleeper-ish look.

lol too bad you dont live closer, I have an extra 400 block along with a 383 & 440 laying around

 

[LocuMob]

lol too bad you dont live closer, I have an extra 400 block along with a 383 & 440 laying around

I'd probably snatch them up if the price was right.

 

[furious70]

How deep do you want to get into it?
Those early 383's can be woken up with intake and headers. Like was said before, it's got a baby cam. The heads are also pretty poor.
A lopo 440 is going to suffer from it's own shortcomings

 

[Scotty76]

Intake, cam, carb, heads, headers, exhaust.

I’m building a 2.5” system for it but for now I’m using the manifolds. I will probably run the TTI headers, I had been holding off because I wasn’t sure what motor was gonna be in it long term.

 

[71Polara383]

There's no replacement for displacement. 440 is going to make more torque. 383 is going to rev higher.

Either one can be fun. Build up the 383. The gear is going to be the biggest kick. 2.76 is miserable. 3.23 is better. 3.55 is good. 3.91 is fun. 4.10 is a party.

 

[Just Carbs]

In the mid-seventies I had a 68 Road Runner 383/auto/3.55 that would not run with my 69 Dart GTS 340/auto/3.55. Apparently, the little Dart 340 made more power than Dodge said it did. Anyway...
I also had a heavy 66 Fury (Sport?) 440/auto/3.23. It was much slower than the other two. Alot slower. And not just because of the rear gear. Too much weight!

Then came the 70 Super Bee 440 six-pack/auto/3.90. Night and day faster than the others, by many buses in the 1/4 mile. And not just because of the rear gear. I thought the car was a monster at the time.
All the cars were bone stock and very healthy.

What I'm saying is that I think the Polara is "too heavy" to be trying to get it to go fast with a little spin happy 383.

So, pick your flavor of big cubes.
As for compression? Well, then everything is going to center around that, isn't it? Or can you find a way to pressurize some air on a low compression big motor under the hood?

I can tell you from experience, after racing offshore 427/454/540/572 chevy blower motors, and a few 440s, that it's a lot easier and cost a lot less money to get a lot more power from a super charger than trying to get a motor to suck the air in by itself. It will cost a LOT of money to build a straight motor that can take the strain on the crank, rods, heads, pistons and valve train for the same power and longevity by comparison that can move that weight.
The stock 1975 440-blower motor don't need no fancy heads, no fancy cam, no fancy rockers, no fancy crank, no fancy pistons, no fancy rods, no fancy exhaust, no fancy carburetors. All it needs is 4 pounds of boost to knock the tires off a 3.23 gear big car from a 30-mph cruise when you step on it.
Getting the tires to hold the motor down, that's another thing to work out.

 

[Turboomni]

My 69 Fury III had a tired 440 low compression engine so I went to a stroked 440 to 505 . Nothing fancy compression wise and the "Big Boned Gal" as I call her will eat absolutely any type gas offered on the street , any time , anywhere and put out gobs of torque easily, and will want more.....gas. I fricken love it. She doesn't have to race anybody and no one has seen anything like her ever or in 40 years if old enough.

 

[71Polara383]

My 69 Fury III had a tired 440 low compression engine so I went to a stroked 440 to 505 . Nothing fancy compression wise and the "Big Boned Gal" as I call her will eat absolutely any type gas offered on the street , any time , anywhere and put out gobs of torque easily, and will want more.....gas. I fricken love it. She doesn't have to race anybody and no one has seen anything like her ever or in 40 years if old enough.

View attachment 649688

View attachment 649689

God I love the 29 roof

 

[Dads300]

If you keep your 383, don’t slap stealth heads on there or you’ll end up with way less than 10:1. Those pre 68 engines have closed chamber heads. If you go to aluminum, you’ll need the small chamber edelbrock or similar. Just a heads up.
Travis..

 

[CBODY67]

When I put 906s on my '67 383 4bbl engine, I still get trace rattle at WOT with the timing set to about 36 degrees total.

As the old Direct Connection Race Manual states, best to run a lower compression ratio with full optimal advance than try to run higher compression at lower advance levels.

NOW, there were many law enforcement entities that used regular fuel (which was 94-95 Research Octane at the time, which equates to 91 pump octane these days) way back when the cars were new. Possible reasoning was that they'd not clatter except at WOT, usually, so no need to spend the extra money on premium fuels to idle around with. Which might also be why the 4bbl motors usually had total advance of 30 degrees at WOT. Yet the 383 2bbls had 36-38 degrees total (in '66-'67 time frame for non-CA engines).

Later, it was discovered by D Vizard that with a good squish action, and no more than .020" between the piston top and the cyl head quench area, higher compression ratios could exist with "pump gas". BTAIM Yet too much advance would make the 8.2CR motors clatter just like they had higher compression.

Enjoy!
CBODY67

 

[weim55]

I would have a question for you, and then suggestion on how to reach your goals:

Old guys like me that reached driving age in the malaise area of the 70s have a point of reference for
“ performance” that is wildly different for younger people from the computer/fuel injection generation.
A well tuned 383 roadrunner is a strong running car to someone like me yet my current daily driver turbo gas VW wagon (that gets 38mpg) would run neck and neck with that old Mopar. My point is if your point of reference of a fast car is something like a current coyote mustang/392 Challenger pretty much anything you do to “hop up” The old Polara is going to leave you disappointed.

Here’s a suggestion: before you start changing anything find a Way to drive or ride in a proper running/tuned old Mopar. A restored stock 383HP would be great on one end at the spectrum and then try on a worked over 440.
Honestly, you may be seriously disappointed with both, and that will answer your question whether to even spin a wrench at all under the hood of that old Polara. If you find you enjoy the experience comparing the two, stock 383HP (which you could easily duplicate for minimal cost) or a complete modified new build, Could be a fun future for you and your 65.

Steve weim55 Colorado

 

[CBODY67]

Yes, "point of reference" is VERY important! The '68 Road Runner with the 383HP, TF, 3.23 gears, and F70-14 tires would usually do 0-100mph in 20.0 seconds (from the road tests back then). That would mean a low 14 second 1/4 mile ET. Not a bad engine combination for that car! THEN or now.

In the earlier 1960s, the benchmark of a "hot car" was a 0-60mph time of approx 7 seconds. That included the 4200lb Mercury Monterey S-55 406 3x2bbl 4-speed with a 3.50 rear axle. Many similar Plymouths and Dodges could do similar, with a TF. Many 383 4bbl cars would do 0-60mph in about 8 seconds. Still . . . good running cars from then or now.

IF it were NOT for the gazillion-speed automatics of modern 4cy cars, most with turbos, the new iron would not be quite as fast. Especially with the 4.50+ low gear ratio in the automatics. Take a Hellcat and put it in front of a suitable 3-spd TF and watch the performance moderate lower with the same 3.2 axle ratio. Might even feel how weak it can be at sub-3000rpms, too! Not to mention the lower top speed without all of the OD ratios!

Used to be that any 400-425 horsepower engine could be a beast to live with, but with all of the modern electronics, not any more. PLUS fuel economy is phenomenally better.

End result, then as now, find something that drives well with minimum throttle input and gets 16+mpg on the road. THAT might take an OD automatic (TF 3spd_OD) with a 3.55 axle ratio, but it'll be fun and efficient to drive. Might even lay some rubber, too. Is that doable with a 383 or stroker 383, yes. Just remember one thing about 383s, they have the same bore-to-stroke and "rod ratio" as the Chevy 302 Z/28 V-8. With the right set of heads, a good cam, and a good undercar exhaust system, you can get lower rpm torque and 5000rpm horsepower.

So forget about 6000rpm horsepower numbers. Those big numbers happen at the higher rpms only, not at 2000rpm cruise speeds. Build a "torque motor that rpms" and you'll end up with an engine that is neat to drive daily and still "get on down the road" with little throttle input.

Even my '70 Monaco 383/330 with TF and 3.23s, open the throttle about 1/2 way and the speedometer needle heads "to the triple digits" without hesitation. It KNOWs what to do and does it. Doesn't need 500 horsepower to do it, either.

Enjoy!
CBODY67

 

[Big_John]

Greeetings. I bought a 65 Polara last fall and have been addressing a few things over the winter, it's a fantastic running solid car. I'm not new to working on cars/motorcycles but I am brand new to Mopars, this is the first classic one i've owned, I do have a 91 Jeep and a Ram daily driver. The motor is a 383/4 barrel, it's original to the car. According to what I've found that's a 10:1 motor? I really like the car and the thing runs terrific, no smoke no bad noises, a few minor leaks that I've addressed. However, it is a little bit of a pooch. This winter I was considering the comp replacement for the Mopar Purple 484 cam, 440 source heads, Performer RPM intake and a decent carb. The car will likely see the track 1 time if at all. Current rear is a 2.76 but I'm about to put a sure-grip 3.55 in it. So, I got to thinking - would it be a better idea to do these same upgrades to a 440 and stab that in? I understand there is potentially fab work and the left motor mount needs to be addressed but there are easy solutions for that. I have done engine swaps before so not too concerned there. My question is if I end up with a low comp motorhome or truck 440, am I just chasing my tail? If I can confirm it's from a passenger car 440, what compression ratio where those available with?

So, basically, should I stick with the 10:1 383 or is any 440 likely going to be a better option? Thanks!

Here's my thoughts...

It really depends on what you want... You can't beat cubic inches, but the engine in your car is already running and in the car.

If you find a 440 engine, it's probably not going to matter what it came out of. Unless it's already been rebuilt, a low compression engine doesn't mean much... and the chances of finding a good 440 that doesn't need rebuilding is slim to none.

So, you've got to rebuild it, that will mean new pistons, so you can decide what compression ratio you want. It's my opinion that a high compression engine is great, but thinking down the road... It might become harder to get decent octane gas. The no ethanol gas around here has dropped octane in the past couple years... So that's some food for thought.

Actually, I'd look at a stroked 400 before the 440... Probably the same price once all is said and done.

If you do go to the 440, you also might want to rethink the 3.55 rear too. A 3.23 might be a better choice, but that's going to depend on your combination.

But here's what I really think... Leave the 383 in it and do the rear change before you decide. That gear change is going to wake the car up quite a bit.

 

[Scotty76]

Here's my thoughts...

It really depends on what you want... You can't beat cubic inches, but the engine in your car is already running and in the car.

If you find a 440 engine, it's probably not going to matter what it came out of. Unless it's already been rebuilt, a low compression engine doesn't mean much... and the chances of finding a good 440 that doesn't need rebuilding is slim to none.

So, you've got to rebuild it, that will mean new pistons, so you can decide what compression ratio you want. It's my opinion that a high compression engine is great, but thinking down the road... It might become harder to get decent octane gas. The no ethanol gas around here has dropped octane in the past couple years... So that's some food for thought.

Actually, I'd look at a stroked 400 before the 440... Probably the same price once all is said and done.

If you do go to the 440, you also might want to rethink the 3.55 rear too. A 3.23 might be a better choice, but that's going to depend on your combination.

But here's what I really think... Leave the 383 in it and do the rear change before you decide. That gear change is going to wake the car up quite a bit.

Can’t argue with any of that. That’s probably the current plan going forward.