Any Transmission Guys here?

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Honey Badger

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Nobody can really give any accurate ideas on what may or may not help you without knowing a few things that have already been asked. There's no need to touch the transmission for anything.

1. What are the current gears? All this is moot if you're already running 3.55 gears.
2. Are the current tires stock size?
3. What load weight if any do you want to tow?

Keep this in mind also. Say you are currently running 4.11 or 3.73 gears. Those lower gears are doing "work" to help the transmission and engine(fuel consumption) to move your truck. If you go to higher gears say 3.55, something will have to make up for the "work" from gear loss. So your options would be to have a heavier foot, more fuel....or not use 5th gear and stay in 4th gear to make up for the gear loss from the gear swap. This would all be true at highway speeds unless I'm vastly underestimating the 460hp/tq.
Yeah. That makes sense. I will mostly just be hauling stuff and driving to work and back. My Daughter is 13 so I have 3 years before I give her my Charger. The old Ford will then be my to work and back home vehicle. I work 1.5 miles from home so it wont be that bad…… I hope. Lol
 

dennishoddy

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Don't go 351M, they are gutless. If you go that route, go with the 400 which is the same block. and much torquier. :thumb:
Spend 7 grand and get a 7.3 liter godzilla with 430 HP and 475 torque crate engine.
Adding a Pro-Charge bolt on kit, you can get 524 hp and 557 lb-ft of torque, for a "starter".
 

swampratt

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MPG and few vehicles I have driven.
1 ton ford van with 300 inline 6 with 4.56 rear gear Carbureted.
10 MPG no matter what.

3/4 ton Ford truck 460 Carbureted no overdrive rear end ratio? 8 MPG trailer in tow 98% of the time.

3/4 ton Ford truck Rear gear? 400" with 260H cam and 2 barrel carb automatic trans NO overdrive.
12MPG I recurved the distributor and tuned the carb to no end.

1 Ton Chevy 1980 Tow truck 4.11 gears granny 4 speed (repo truck) had a 350" stuck in it and 4 barrel Quadrajet carb 8 MPG.
Owner pulled the stock 454 from it because it got 6 MPG in tow duty.

This vehicle did not move unless it was to tow a car or go get one to tow.
I stuck the 454 back into it assuring the owner I could wrangle more MPG than the 350.
He agreed to let me tweak it and if I failed I had to stick the 350 back in.
I was 20 years old.
I removed the vacuum advance and put a quicker timing curve in it and adjusted the APT piston stop on the Quadrajet carb.
12 MPG.

3/4 ton 1994 Dodge with 360" and OD trans rear gear? 10 MPG no matter what.
That truck annoyed me to no end with the terrible MPG for something with fuel injection and an overdrive and light weight 4900 lbs.

If I had kept it another year i would have stuck a Quadrajet carb on it.
Stupid thing was fast though.

3/4 Ton Ford van 3.50 gears OD automatic and 351W HO with a 4 barrel carb.
Stock it got 10-12 MPG. I tweaked it to 14.

My 1984 Ford van 3.50 rear gear not using the OD 302" bored .030 over ported small valve heads
flat top Keith Black pistons 260H cam advanced 4 extra degrees.
2 barrel intake Ported and ported exhaust manifolds 3" single exhaust .
5600 lbs No passengers minimal fuel.
Quick timing curve and well tuned carburetor 17.6 average MPG.
Got as much as 19.8 and as littleworst was racing myself up Pikes Peak 8 MPG.

If I towed my bayliner at 60 MPG i would get 17.6 MPG it I went 65-70 I got 16.7.

2012 or 2014Chevy 4x4 truck 5.3 with 6 speed trans and rear gear? 12-13 MPG stock.
2 different trucks mix in town and some highway.

Towing small Jeep on rented small U haul trailer 8MPG.
I was Horrified with that made me toss stones at the 5.3 GM engine for truck duty.

2018 Ford 4x4 ecoboost 3.5 V6 10 speed rear gear? 24 MPG 2000 lbs of camshafts in the bed OKC to Huston highway.

Pulling my 20 foot pontoon on a shorter trim 12.1 MPG. 65 MPH

My 1957 Chevy 4 door with a bit over 10.5 compression 350" with 750 Edelbrock carb No overdrive 3000 stall TH350 and 3.00, gear AC on, pulling same Pontoon boat to Texoma.
11.6 MPG GPS used. 280H comp magnum cam.

Not the best tow setup.
That same engine with 3.25 gear and tighter converter with 268H cam on a 112 LSA with a Ported cast iron Quadrajet intake got 18 MPG pulling a small bayliner .
14 MPG with a Performer RPM intake.

There is power in the tune Power in the castiron intake due to smaller runners and the heat of iron to help atomize fuel and MPG to be had with your foot out of it.

In all my driving and testing of MPG heat is a big factor.
If I run my engines at 140 °F MPG takes a hit 160 is not much better 185-190 is a sweet spot

In the 200° power takes a big hit and detonation begins so very light foot is needed.
For my stuff anyway.

The 351M I have had and is not too bad but the 400M like was stated will run circles around it.

Last one.
1980 1/2 Ton chevy with original rear springs and a full stack of 3/4 ton springs and a 3/4 ton rearend.
455 Oldsmobile with the small J casting heads Ported. Cam from a 403 Oldsmobile Ported cast iron intake manifold quick timing curve and Quadrajet carb. 15 MPG no matter what. TH350 transmission Rear gear?

Used it for a roofing truck and you could stack shingles 8 foot high in the bed with the 8 foot sideboards we installed. Same MPG 15 and did not feel like you put a load in it. Yea same tune and quick timing curve as many other Carbureted engines I ran.

Best Auto MPG ever for me was a first Generation Civic carbureted and stick shift trans. 53 MPG driving like you stole it.
Car was very light though. 1500 lbs.
 

Honey Badger

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MPG and few vehicles I have driven.
1 ton ford van with 300 inline 6 with 4.56 rear gear Carbureted.
10 MPG no matter what.

3/4 ton Ford truck 460 Carbureted no overdrive rear end ratio? 8 MPG trailer in tow 98% of the time.

3/4 ton Ford truck Rear gear? 400" with 260H cam and 2 barrel carb automatic trans NO overdrive.
12MPG I recurved the distributor and tuned the carb to no end.

1 Ton Chevy 1980 Tow truck 4.11 gears granny 4 speed (repo truck) had a 350" stuck in it and 4 barrel Quadrajet carb 8 MPG.
Owner pulled the stock 454 from it because it got 6 MPG in tow duty.

This vehicle did not move unless it was to tow a car or go get one to tow.
I stuck the 454 back into it assuring the owner I could wrangle more MPG than the 350.
He agreed to let me tweak it and if I failed I had to stick the 350 back in.
I was 20 years old.
I removed the vacuum advance and put a quicker timing curve in it and adjusted the APT piston stop on the Quadrajet carb.
12 MPG.

3/4 ton 1994 Dodge with 360" and OD trans rear gear? 10 MPG no matter what.
That truck annoyed me to no end with the terrible MPG for something with fuel injection and an overdrive and light weight 4900 lbs.

If I had kept it another year i would have stuck a Quadrajet carb on it.
Stupid thing was fast though.

3/4 Ton Ford van 3.50 gears OD automatic and 351W HO with a 4 barrel carb.
Stock it got 10-12 MPG. I tweaked it to 14.

My 1984 Ford van 3.50 rear gear not using the OD 302" bored .030 over ported small valve heads
flat top Keith Black pistons 260H cam advanced 4 extra degrees.
2 barrel intake Ported and ported exhaust manifolds 3" single exhaust .
5600 lbs No passengers minimal fuel.
Quick timing curve and well tuned carburetor 17.6 average MPG.
Got as much as 19.8 and as littleworst was racing myself up Pikes Peak 8 MPG.

If I towed my bayliner at 60 MPG i would get 17.6 MPG it I went 65-70 I got 16.7.

2012 or 2014Chevy 4x4 truck 5.3 with 6 speed trans and rear gear? 12-13 MPG stock.
2 different trucks mix in town and some highway.

Towing small Jeep on rented small U haul trailer 8MPG.
I was Horrified with that made me toss stones at the 5.3 GM engine for truck duty.

2018 Ford 4x4 ecoboost 3.5 V6 10 speed rear gear? 24 MPG 2000 lbs of camshafts in the bed OKC to Huston highway.

Pulling my 20 foot pontoon on a shorter trim 12.1 MPG. 65 MPH

My 1957 Chevy 4 door with a bit over 10.5 compression 350" with 750 Edelbrock carb No overdrive 3000 stall TH350 and 3.00, gear AC on, pulling same Pontoon boat to Texoma.
11.6 MPG GPS used. 280H comp magnum cam.

Not the best tow setup.
That same engine with 3.25 gear and tighter converter with 268H cam on a 112 LSA with a Ported cast iron Quadrajet intake got 18 MPG pulling a small bayliner .
14 MPG with a Performer RPM intake.

There is power in the tune Power in the castiron intake due to smaller runners and the heat of iron to help atomize fuel and MPG to be had with your foot out of it.

In all my driving and testing of MPG heat is a big factor.
If I run my engines at 140 °F MPG takes a hit 160 is not much better 185-190 is a sweet spot

In the 200° power takes a big hit and detonation begins so very light foot is needed.
For my stuff anyway.

The 351M I have had and is not too bad but the 400M like was stated will run circles around it.

Last one.
1980 1/2 Ton chevy with original rear springs and a full stack of 3/4 ton springs and a 3/4 ton rearend.
455 Oldsmobile with the small J casting heads Ported. Cam from a 403 Oldsmobile Ported cast iron intake manifold quick timing curve and Quadrajet carb. 15 MPG no matter what. TH350 transmission Rear gear?

Used it for a roofing truck and you could stack shingles 8 foot high in the bed with the 8 foot sideboards we installed. Same MPG 15 and did not feel like you put a load in it. Yea same tune and quick timing curve as many other Carbureted engines I ran.

Best Auto MPG ever for me was a first Generation Civic carbureted and stick shift trans. 53 MPG driving like you stole it.
Car was very light though. 1500 lbs.
So it looks I will supporting the oil and gas industry for some time to come!! I like the old girl. She is family! Lol
 

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