Everything you need to know about gears
Do you need a 12 bolt? Do you need posi traction? How you can properly select the right gear ratio for your car or truck, or classic muscle car.
source
Everything you need to know about gears
Do you need a 12 bolt? Do you need posi traction? How you can properly select the right gear ratio for your car or truck, or classic muscle car.
source
Very good vid as always, I do have to mention the reason for the popularity of the Ford 9 inch is so misunderstood. Ford designed the 9 inch to be quiet and strong, how did they do that, by using a Hypoid gear or lowering the pinion gear lower on the ring gear, instead of on a Bevel gear which is on the the C/L. What this did was to allow for more gear tooth contact (stronger) and quieter running gear set.
But here is where the big misunderstanding really comes in. With the advent of the modern Pro stock car, the wanted to lower the drive train, so the Ford 9 inch was 2.250 lower off the C/L, so now the drive train can sit lower in the car. The gears are stronger yes but they do take more power to rotate.
One of the most over looked rear ends for street cars is the 8 3/4 Chrysler, strong and light and very inexpensive to build for at least 75% of your builds. In the 70s we ran a H/G Nova with a Dana 60 rear end, it had a 7.17 gear which only had 3 teeth on the pinion gear. 10 runs and you needed to change gears.
Did you see the video on calibrating the valve height micrometer?
https://www.youtube.com/watch?v=GfsX1eCG4VU
Never ever ver set up a race engine to run off of the chip and only use the chip to protect the drive train. The cylinder chamber pressure becomes very inefficient and dangerous to the piston when the spark plug only fires intermittently on the chip. Piston damage is a sure thing.
Great info, keep it coming!
Alan, thanks for doing what you do, I like all your content. I wish I had kept my Z-28, it was the quickest car in town back in 1973… It was a '70 model. They put the M22 in those but was also the last year for the 12 bolt rear differential. I think first gear was absolutely useless in my Zed sled. You did a good job explaining why that 2.20 first gear was used in those car's. I think my account thumb nail has a picture of the old Camaro. One more thing, I keep having to subscribe to your channel, is this a problem you have come across.
First gear is a lot different between the m20 and the m21. Well second one third also, but the leave of the m20 is the ticket.
I've got 3.64 in my 10 bolt an 700r4 355cu. Was considering 3.73… my converter is a 1900stall.,I'm using XR264HR-10 comp cam.
Back in the day had a 66 Beaumont with a powerslide & a 12 bolt 4.56's. 55 MPH on the highway with G60-15's!
AG, I put a 3.55 gear in my 73 Corvette and took out the 3.08 or 3.36? The 3.55 is an all around gear, but var would of ran much faster if I had put a 3.73 in it. Turbo 400 trans with a B&M 3,000 stall converter…
You are using the shim to setup the pinion depth into the ring gear…
Gear ratio depends on the weight of car and how much hp and torque the engine puts out, tire size also…
I forgot about trans ratios too… converter stall.
AG, it takes more hp to pull a high gear or lower gear… It takes more for a lower gear because engine runs out of power, too much rpm…
What about the crush sleeve AG? 9" Ford doesn't have a crush sleeve…
The 2.20 ratio is for cars with a lower gear rearend… I always like the wide ratio with a 2.54 ratio first gear… Later 10 bolts are strong as a 12 bolt rearend. Early 10 bolts break fairly easy, especially if they are a single track…
Enjoyed your video, my set up is a 454ci with a NP440/MY6 and 10 bolt posi 3.8:1 gear. The final drive in first is 9.52:1 and 2.25 in forth which is .73:1 all in a 78 nova. I don't think a street car can do much better other than go up to 3.42:1 gear for a better OD ratio. I have a 2.41:1 gear set if I want to go for a land speed record.
I broke alot of muncie trans with a 2.73 rearend… 9" Ford rearend is the best, thats what I run in my fast car with a bigblock! 35 spline axles 10 bolt pinion support Ultra case Strange and axles… 4.86 gear for a 8 sec. car…
Changing from a 2.73 to a 3.55 is like day and night on the power of the car!
Tearend gear needs to be within the power range the car is being driven in AG.
Real cars don't have a clutch or stupid names like rock rockcrusher.
The worst thing you can do is continually use the revlimeter chip when the ignition box shuts off cylinders it creates vibrations in the engine and wears out the engine prematurely. Read the Rehe and Morrison engine building book. They can tell that every time they tear down an engine, the same engine used for same type of racing engine that uses the revlimeter all the time that engine is completely worn out. Then engine that dose not bump against the revlimeter is always still in good shape
Many muscle cars had big block engines with 4 spd transmissions. The same car with a 6 cylinder water heater only came with three on the tree. My Dad always said the 6 cylinder cars needed the 4 spd trans as they did not have the torque the big engines did. I know a guy that had a 68 Mustang with 390 and 4 gear. When out on a date he could drive around in 3rd gear. Proved what Dad said.
Actually, the right rear wheel will unload and spin with an open differential… unless you are launching in reverse.
just gotta say I love the channel and the wealth of info you are giving away for free is invaluable.