So my truck is not as fun to drive as I hoped. It's a dog pretty much and drinks gas like no other vehicle I have ever owned. Just finished a bunch of work on it to make it reliable so I am keeping it for sure. But, it definitely needs some changes in the power train to increase the fun factor. There a are a few things I am looking at changing - not necessarily all at once or even at all, just trying to bounce ideas around and see what others may think.

So first off, the granny low NP435 is rough - three usable gears. 'Nuff said. Yeah, this thing was built when trucks were used to do actual work and I'm good with that but not at such a grunt level. Seems like the NP435 was designed for tractors and adapted to trucks. Highway driving is the worst - the gear spread is too wide to keep it in the power band. And after enough miles, rowing that giant stick can get tiring.

Besides the trans, the engine is really inefficient. It's a stock, long block 400 (very low comp.) with an MP .484/284 cam and an Eddy Performer RPM hi-rise intake. (p.o. built it that way) Small tube headers into dual exhaust but it all goes into a single muffler. Currently has a Holley 600 on it. Rear gears are 3.23.

I am looking for better all-around drivability - mainly, crisper throttle response, better highway manners and some increase in mileage. So what changes will yield the best results? I know the cam is big factor - no cylinder pressure, not enough rear gear, gear spread in the trans is too wide. Of course I can change the cam but then I still have a stock lo-po long block with an 'RV' type cam and the same driveline. How much better will that be?

I have a bunch of factory small block stuff including a a 1990 roller cam block. I'm thinking a flat top piston 360 or 408 would be a big improvement over the 400 across the board. The 400 will absolutely need new pistons to make it perform better which means the motor has to come out. I could build the 360 and swap it in when it's done without being down for too long. Fuel injection is on the list of priorities too.

And the trans. I'd like to keep it a stick. What would be the best option here? I have an 833 OD on the shelf that needs a rebuild. I would need a bell housing but they seem somewhat readily available. I have seen a few NV4500s for sale on CL for relatively cheap but given that I don't really like the NP435, I'm not sure if that is a good choice or not. I believe the NV4500 MAY bolt up to an NP435 bell so that could save some coin.

In addition, I also have some empty rear end center sections around that could be built any way I wanted so I'd probably match the gear to the rest of the combo. The current 3.23 does me no good with the way the truck is built. Takes about 30 miles to get up to speed.

So what would be the best bang for the buck? Or, what's the first thing that should be changed that will make the most difference? I think it's trans. Trying hard not to have the whole truck apart and spend huge amounts of money but it may be unavoidable at some point to get what I want.

Not really looking for specific answers about this part or that but rather looking at the whole picture in relation to the stated goals. Honestly, I am almost a little reluctant to post this since it's pretty subjective and kind of vague but I figured I'd give it a shot and see what happens.

So what would you do?

Thanks for any input.

- Greg

Its not the trans holding things back, cam is a big one, that cam is way wrong for your ride. A newer desighn fast lift cam with about 200*@.050 single pattern with as much lift as possible and 108LSA would work waaaay better with the low compression. The 600 holley is too small, 400 inches should have at least 750 CFM, small carbs tend to get real rich on too big of an engine when the RPM climbs so jetting at least probably needs significant adjustment.

I built a stroked SB for a customer with mag heads and small cam in a 4x4 85 with 3.23 gears and it pulls like an animal even with a bob cat on the open trailer behind it going up mountain passes. The cam was just a little bigger but the compression was 9.5 ish. It is an 727 with a low stall converter, about the worst trans for performance.

With 3.23 gears the granny gear could be used to take off, don't know why thats a problem. I had one with a 360 TBI engine and used it from dead stops even with the 4.10 gears.

like Dave said.

You won't find many moparts members who like the 484 Street Hemi cam, me included. That cam is more suited to high compression motors.

Its already been mentioned...

That Cam is killing that engine..

Carb is small too..

a833 would be Ok with a 360. Would bolt to the newer np435 dual pattern bellhousing too. Think late 80s.

nv4500 will NOT bolt to a np435 bellhousing.

Don't know how you guys are using 1st gear to take off unloaded in a np435 since its barely synchroed. I only used mine in my 83 and 88 in the woods or hay fields. 3.23s in the 88 and 3.55s in the 83.

nv4500 in my 92 is awesome. Shifter is closer and ratios are different.

You will thoroughly enjoy a 360 magnum , nv4500 combo with 4.10s

Let's quantify what the problem is. What mileage are you getting? What size tires? Is the speedo and odo accurate?, lifted? Etc.

No go on the 833 if 4wd, the only vehicle that used that combo was some early gm diesels. You're not likely to find one for the tail housing.

Is the dist tuned with a good advance curve? Carb jetted right?

I have a mild 440, 435 trans, 4.10 with 37" tires, 1 ton running gear in a heavy 4x4 trailduster that sees mostly street miles. Sure 1st gear is useless and shifts hard, sure she only gets 10 mpg with a tailwind but shes still lots of fun to drive once you get use to shifting that trans. I can break loose all four tires on pavement. Yours is a two wheel drive, short bed, figure that big block out and she'll get fun.

Good closed chambered heads(63-64 cc) and thin head gaskets will help.
As stated bigger carb and some retuning is needed.

I have to wonder what the truck actually does run like. I've owned more then a couple 400ci with the 435 trans, and they will flat whoop a 360 in the same truck. Maybe your tires are too big, what size tires do you have on your 4x4? Big tires will kill the fun and mpg in a hurry, especially with 3:23 gears. 8-10 mpg is pretty standard in a 4x4 Dodge truck. If you are expecting a race truck, everything is wrong.

The carb is small, the cam is wrong, I suspect the dist curve is out of spec, and I suspect you have very big tires on your truck. I'd start off with smaller tires, a bigger carb (dialed in), and dial in the dist. Then give us some real numbers. Gene

Truck is 2WD. Can't remember what the tires are off the top of my head, maybe like a 235/75/15 or so. Yoko SUV tires.

The truck drives OK I guess but it could be better. The trans drives me nuts. Honestly, first gear is useless, it's not synchronized and is like a 6:1 ratio. I've used it a handful of times it's not practical for regular street driving.

The main issue with the trans (for me) is the gear spread. Lets say you're around 45 mph going up a longish grade in traffic and in third gear. For whatever reason, the car in front brakes. I'm over 3 grand at about half throttle and I have to shift out of gear. Then I am in no mans land - if I go to 4th, the RPM drop is too big to keep momentum. If I go back into 3rd, I'm over the normal RPM for that speed. I don't like that dance.

The 600 cfm carb was a recent addition. I had a 3310 on it and it seemed to be better overall it actually did get a little better mileage and ran smoother than the 600 so maybe I will change it back.

Just think the whole combo is not very well thought out and needs some major changes.

In that scenario a cam swap would help a lot as you would have TQ down low to still pull when you hit 4th, it would not feel soft down low.

I have been through this scenario. I sold my orange shortbox for the same reason. horrible mileage. may have got 7 mpg. tuned well. just a pig on fuel.
my opinion...probably wont be popular. low blocks are not for trucks. especially a 160-ish hp 400. pitch it put a 440 in it or a good magnum motor.

I will never run a stock low block ever again unless its for a resto.

OK if you need to spin 3000 in third to go upa grade with your current tire size, something is wrong. A big block should be able to lug that in fourth easily.

Wow that's bad.

As said by a few the big prob with your motor is the low compression and that cam. first thing to change is that. next is the exhaust. Free it up let it breath, very important. yeah the trans sucks but you need to make the engine run right first. Change the cam and exhaust get the distributer curve right and set up the carb. the 400 is going to use some fuel but it should not run like a pig. unless you want to start with a whole new engine that's what needs to be done to the 400 to make it right.

Ever driven anything with an NP435? They were put in trucks that actually did work. Again, for me at least, they are not practical for regular driving.

Here's the results from the Wallace Racing RPM drop calc.

Click here for the calculator.

Gear Shift Drop Calculator
RPM: 3,000
Rear Gear Ratio: 3.23
Tire Diameter: 28"

Gears in Tranny:
1st Gear Ratio: 6.68:1
2nd Gear Ratio: 3.34:1
3rd Gear Ratio: 1.66:1
4th Gear Ratio: 1.00:1

After 1st Shift: 1,500 RPM. 50.00 % RPM Drop
After 2nd Shift: 1,491 RPM. 50.30 % RPM Drop
After 3rd Shift: 1,807 RPM. 39.76 % RPM Drop
1st Gear is 11.59 MPH at 3000 RPM
2nd Gear is 23.17 MPH at 3000 RPM
3rd Gear is 46.63 MPH at 3000 RPM
4th Gear is 77.40 MPH at 3000 RPM

A few have mentioned timing. Distributor is 'new' (reman) one light spring, one heavy. 18 initial and 38 total. Has vac. advance, did not verify how much the vacuum is adding but the canister is new and works (verified with vac. pump). New Champion #14 plugs, new Taylor wires, new rotor, MSD Blaster 2 coil, new engine harness, ballast resistor. Before I changed the carb to the 600, the plugs were a nice light brown and the firing ring was right in the middle of the bend of the ground strap. It's right or at least as right as it could be with the current combo. Timing is not the issue.

If I stick with the 400, the cam will be changed for sure. I guess I'm just trying to figure out whether a cam change alone is worth the effort without doing anything else?

Full dual exhaust in these trucks can be a little tricky with the gas tank along the driver side. I'm sure it can be done, just another hurdle to contend with.

Could probably use another 2 degrees initial but certainly needs about 4 degrees more total and that should be all in by 2000 or 2500 at the latest.

Dual exhaust is over rated an equal cross section single flows more and retains heat better. Make sure you have good merge points and you should be fine with a single 3 or 3.5 inch pipe.

Go back to the 750 and lean out the jets till it starts stuttering and go back up one jet size.

Open your plug gap to about .045 with that ign it should produce a hotter spark and light the crappy low speed mix better.

Thats about all you can do without tearing into it.

I am convinced in the cam making a huge difference. Get a custom made cam, the few extra $ will be worth it but even a small summit cam advanced a couple degrees will be better than what you got, I just hate tearing into my junk and sort of fixing the issue. It will reduce overlap, close the intake earlier for more cylinder pressure and open the exhaust later for a little extra push on the crank before releasing cylinder pressure. It will result in more power everywhere you need it and you may no longer beconcerned with the RPM drop. A big RPM drop ain't as bad when there is TQ down low to take over after the shift.

Have I driven np435? Yes quite a few. But if your engine can't maintain 45 uphill in a 2wd ramcharger, something is wrong. My 77 crew with a 360 can do that with much taller tire.

I agree. My 440 74 power wagon pulls like a beast in fourth going up a hill with 33-12.50-16.5's. It's mostly stock. 40 over flat tops, edelbrock performer intake and street avenger 670 carb (what I had at the time that worked).

Fuel mileage is roughly 15mpg. If I drive it like I stole it, I can guarantee it'll get about 8. But I have a heavy double return spring on the throttle. Keeps me out of the pedal.

Good luck with that 400! I hope you get it sorted out. A big block 2wd should be a hoot. No reason a 400 shouldn't perform well. If it were me, I'd throw some Pistons in it. Raise the compression. Without compression, your choices are limited.

Keep us updated!

You get no credibility comparing a 440 with a 400.

I agree that am is waaaaay too big, it's something like 234 at 50 lift. I'd go with a Hughes with in the neighborhood of 208 intake at 50.

You don't need duals but as said above a single 3 or 3.5" will do just fine and not cause as many clearance problems.

For the carburetor I'd use a Holley Street Demon 750. If you're using another squarebore Holley I'd suggest the newest model available. They had better metering than the old standbys like the 3310 or 1850. My Street
Avenger 570 is worth 2-3 mpg over a "tuned" 1850. I think it's the part-throttle stuff that's different.

I know what you're saying about the NP435. My NP420 is about the same. Won't pull a hill in Fourth at altitude but Third is screaming the engine at 40
mph. NP445 or 4530 is a way better gear spread. The NV4500 is nearly the same as the 435 with a Fifth gear so in the scene I'm talking about it's just as worthless. The A833 would be better, just not the OD version. You have to look at the gear splits.

R.

PS: Compression and squish would help a lot. The KB 215s with stock 400 rods and a 3.75 crank would work too, you'd have a lot more torque in the midrange where the 400 is lacking.



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