19newport72

Hi I have a 1972 newport. I rebuilt a 440 for it let me know if you guys need the specs to make a good decision here. I'm going to finish putting a 69 A-833 4 speed in the car. My cam in the car required a 2500 stall. (Thought that info may help) I'm running stock gears right now. (2:76) in a 8 1/4 rear end. That will be swapped out for a 8 3/4 this summer. What gears should I run? The max speed this car will see is 55. I won't drive it far. Long story short my brother has a 79 camaro and swears up and down he will smoke my newport! So I need to make sure I do this rear end right! And yes I will be using sure grip. I'm thinking 3:55 or 3:73 gears. What do you guys think? Thanks for any help.

78D200

Why is the max speed the car will see is 55? Is this a one time race down a drag strip? What will the car be used for? Daily Driver? Weekend cruiser? Weekend warrior? A mix of everything?

For all around good performance without running down the highway at 3500 RPM, I'd go with the 3.55 gears. If you want performance only, go with a set of 3.92 or 4.10 depending on the power band of your motor.

PK1

For stop light, 0-60 or 1/8 stuff use 3.73. Keep in mind there is a balance between gearing and traction. Some folks prefer a smaller rear gear because the leverage of the deep one will cause traction problems so the advantage is lost in wheel slip. You have a big torque motor so keep that in mind.

Gorts 5th

im running a 3.90 rear gear it's fine for my 318 but i can see a big block smoking the tires with this gear
a new port is a heavy car isn't it
to beat that camaro you may need tall gears but not to tall 3.55 what's your final drive gear in the 4 speed
with my 518 the od drops my highway rpm's down too 2000 but i think you got a 1-1 final drive ratio.

19newport72

Yes my final drive is 1:1. And the reason this car will only see 55 is because that's the highest speed limit around my house. I don't drive the cars much and I don't care for beating them much. But this one is more of a weekend warrior. I was concerned that 3:73s would just make burnouts. So maybe 3:55s? This car will never go on the highway(65 cruising) it will cruise around down which is all 35 mph besides one road is 55. Unless I'm opening it up obviously. And yes this is a big car but I will say when I had it running last summer even with that auto the 440 would light the tires up easly. With 2:76 gears. But that was only one tire. It moved that boat very well!

440roadrunner

The answer depends on how you are going to drive the car, any mileage you expect, and the SIZE OF the rear tires.

I have fairly tall tires, about 28" on my 67 Dart, with a Ford 3.89 9" axle. It runs over 3K RPM at 70 and for the way I drive the car is just right.

So here's what you need to do:

1--Look at the size of the rear tires, or if you are thinking of changing them, use that size. Google them up on the www to find out the size

2--Decide what the cruise speed you are going to see (55 seems way low to me) and decide what RPM you are willing to tolerate.

3--Plug those figures into a www calculator, there are hundreds. Google. This will tell you the final ratio.

PURPLE HORONET

If the car will only see 55mph an no highway use, why just settle for a all around gear. 456 and get-er-done

pro-tech

3:91 is a good gear for a large car. that car weighs probably 3000 to 3500 pounds so up against a 2800 Lbs camaro you need all the help you can get. A low gear but not to low. It doesnt sound like much of a race at 35 to 55 mph. LOL

19newport72

Obviously this car can do over 55. You guys mention cruising speed. I won't be cruising at 55 in my town unless I drive up and down the same road all day. I'm looking for a gear ratio that won't have me shifting constantly like a rice burner. Ill check out the calcs mentioned. Sounds like my best bet. If I can do 120 mph top that's plenty. But I want to hold a decent rpm around town instead of the engine screaming doing 55 mph..... This car will never cruise over 55 mph. I won't drive it on the highway. My brothers camaro has 3:42s and they seem alright. The 350 is just too weak. That's why I'm thinking 3:55s because my 440 has a lot more power

TVLynn

That Newport probably weighs closer to 4K lbs "B" is around 3500. 2.76 or 2.91 gears are great if you like running 100 mph across the desert 3.55 is the best compromise. The car may be faster if you keep the auto.. Make sure your A833 has the HEMI 18 splines. Maybe some street drag radials on the back

John Van

Hmm, A big block and a 4 speed in a heavy car, forget the 8 3/4 rear and step up to a dana 60. been there,done that! For what you seem to want any ratio from 3.23 to 3.73 will work.

19newport72

The car weighs about 4200 pounds LOL! Now that's a tank. I drive the car easy whenever I drive it which is maybe once a month. But I just want a car that will get up and go fast when I want to. My cam rpm range is 1800-6000 10 to 1 compression edelbrock intake (can't remember which one) I think the performer. Holley 770 street avenger. 440 source connecting rods. 906 heads with only pocket porting but ill probably change those out for my 915s eventually. Hooker super comp headers. 3 inch duals. And thanks for the input. I'm leaning towards 3:55s. I don't want to go to crazy or else I think the car will just burnout instead of grip on stock tires. I like the stock appearance but it obviously sounds nowhere close to stock. Hopefully the weight goes in my favor also to help grip good.

19newport72

Why do you think I should go with a Dana 60? I have one sitting in my old cummins truck and I thought it was good for nothing! Or maybe that's a 70? I can't remember everything.

19newport72

How could the car be faster with auto?

Gorts 5th

Well out of the hole you can side step the clutch and sit and spin.
and the auto will always out shift a 4 speed.
my 518 has a 2000 rpm stall and when i mash it to the floor from a dead stop she squats and launches. no tire spinning just pure acceleration.
and when she shift's it's like a second, and shes in the next gear, no pause in pulling due to having to depress the clutch.

Archer

19 -

Unless you are really, REALLY good at clutching (and even if you are), a properly setup auto, including a manual valve body and an appropriate stall on the converter will usually engage and shift quicker than a 4-speed, for the reason Gorts gave.

Now, there are going to be differences of opinion on this, but that notion has been around for some time.

The 3.23 or 3.55 are most likely your best bet.

Archer

Gorts 5th

Archer is right
i agree 3.23 or a 3.55 gear will be in a ideal range.
if you get a overdrive trany, 5 speed with a 0.69 final drive stay with those mentioned gears so your rpms are at a moderate level,
with out my od my highway rps would be around 3500 that's just crazy

19newport72

I had a TCI 727 in it with a 2000 or 2500 stall I can't exactly remember. And the motor was actually a truck motor I bought a while back but when I tore it apart to do the first rebuild I found out it had 6 pack rods in it. I wanted to put a 6 pack on it so I figured why not go with the original 6 pack rods. Well that idea went bad I put the wrong balanced stall in and it threw the stall off balance after maybe 20 miles of driving it which cause the stall to eat the main seal and pump bushing up. Then it started puking fluid out the front of the transmission and when I dropped the pan I got nothing but metal chunks and shavings. I agree 100% that auto will shift faster than a manual and the car did squat pretty good and grabbed. But I rarely drive my cars and I don't plan on racing them but hey sometimes a rice burner needs to know what real power is! And I want a 440 4 speed so I figure this is my best route besides buying a new car and rebuilding another motor for it. Anyways. Thanks everyone for the help when I get the car back together and drive it a little ill make my decision between 3:55 and 3:73! Thanks

jacilynn_s

need some info first what year is the engine? I ask because if its a mid 70s engine with the cast crank instead of the forged putting big tires and gears on the back with manual transmission is gonna put tons of stress on an already weak crank.

OTOH you detuned the engine with headers and a holley/eldebrock alluminum intake so your max torgue is gone so you may need the extra help from the lower gear ratio anyways.

Headers are good if your running open exhaust 3in pipe otherwise the reverb cancels out and increases backpressure at the reducing cone giving you the same performance as a 1 1/4 manifolds. Cast iron manifolds with a 2 1/4 opening have no reverb so on street you get better performance.

Holley carbs work good for 6 months then are pretty much toss as the gaskets and plates warp making them less than useful. Eldebrock is making carter carbs as their performance line up to 750 cfm so why not go with a proven good carb.

Aluminum intakes do not have the crossover. This is good for drag strip racing where your engine is already running plenty hot. Street driving this creates a dead spot when you hit the throttle. A dual plane cast iron intake, also availabe from eldebrock. does not have this problem.

High stall converters are generally built for the forged crank big blocks and not the cast crank. You mentioned the coverter tore the front pump and seal apart which is typical for running the wrong one. The forged crankshafts are much stronger than the cast cranks especially in the rear. Too much torgue on a cast crank can snap the rear of the crankshaft clean.

Mid 70's engines were low compression. I have seen many, far to many, engine rebuilds with wonky cams in these engines, lots of dress up bolt on parts, and they still have next to no power as nobody changed the pistons to higher compression. 8.5 compression is low. 9.2-9.5 is what you want on these engines. If your running the original compression and heads on a mid 70s you can up the compression a bit by using the thin steel headgaskets on rebuilt heads from a 67 engine. It will up you to 9 - 9.1 compression.

Low gear ratio in the rear is nice idea. few problems to contend with though. An 8 1/4 mounting pads are actually different than an 8 3/4 because of the spring angle. You would need to put in 7 degree shims to angle the front of the 8 3/4 up to not vibrate. Its easier to cut the welds and reweld the pads on than it is to put in enough shimes to bring the angle up.

Small tires in the rear are another problem. You need a good set of tires in the rear. My advice is to use stock rims 15/8 ( you may need to get these made as they are like hens teeth to find).

Tires i find goodyears are the best available in normal sizes. you want one that the grip area sitting on the rim installed is no wider than 10 inches across which will just fit into the wheelwheels without major modifications. Put on a simple dogdish hupcap or a period correct wheelcover and its a sleeper.

Or you can do like most go with a tiny tire on aluminum rims, loose your teeth from the road jar and cuss and swear as the air never stays in your tires.