ok guys I need help from the Camaro masters on here.... I'm building a 67 coupe with a basic gm 350 long block and want to use a Muncie 4 speed for the "shifting" feeling what's a good rear ratio to use in the rear end for take off as well as decent fuel mileage?
Best answer... love mine and have an extra set for the 69 restoration that is on deck. Watch the duration or "lope" on the cam as a 4 speed and 3:31's tend to "buck" at slow speed like idling down a driveway.
After 10 years of building the 2.98:1/2.99:1 1st gear 4 speed, it is still my number one seller. Many guys have coupled this low 1st gear 4 speed with a 3.08:1 diff gear, some with a 2.73:1 diff gear, and my personal favorite combination is the 2.99:1 with a 3.31:1 diff combo..
I went from a 3:08 to a 3:55,, Although I love the 3:55's , the 3:08's were a much better hwy gear. I'll be keeping the 3:55's and adding a Gear Vendors OD.
Donnie, the first order of business is to decide which Muncie you are going to run. The wide ratio (M20) transmission has a lower first gear with a wider spread between gears, so it will be easier to get the car rolling with something like 3.08 gears. The M21 and M22 are close ratio transmissions. They have a higher first gear making it harder to get rolling with a 3.08 ratio, but the rest of the gears are spaced closer together, All of them are 1:1 in 4th gear. Listen to what Jody has to say... he's the resident transmission guru.
It is basically all personal preference and how YOU will be driving as well as where(mostly highway and interstate use or all country back roads)
I myself had a built 350 with a M-22 and 4:10's. I loved it! Between the motor, tires and gear ratio - I had a rocketship. Did I get good gas mileage? Nope. Did I care? Nope Did it suck on the interstate for what little interstate driving I did? Hell yeah, but for my style of driving I did 90% of the time on back roads, I wouldn't have changed a thing. If I was doing more interstate driving, probably would have knocked it back to a 3.73 or worst case 3.55 once I had a taste of the 4:10 ratio.
Probably no one would agree with me here, but that is my point. It is all personal preference and type of use.
Infact, I liked that set-up so much that I mimicked it on my current build keeping the ratios as closely as I could to the M-22 but now have a 6-speed T-56. Still driving mostly on back roads with 4:11's, I am mostly in 4th gear. Can get it into 5th on the highway at speeds of 50ish. Only time I can get into 6th is on the interstate.
I but now have a 6-speed T-56. Still driving mostly on back roads with 4:11's, I am mostly in 4th gear. Can get it into 5th on the highway at speeds of 50ish. Only time I can get into 6th is on the interstate.
^^^^, IMHO the ultimate tranny. I went from a 4L60E with 3:73 car to a T56/4:10. With a .50 6th I am doing just under 2k RPM at 80 mph on a 27" tire. On the street its a 4 speed. 5 on the Fwy and 6th if I can "sustain" 65+ mph pending traffic.
With any manual 4 speed or non OD automatic the final gear ratio is 1:1. In those cases you either gear down or go with a Gear Vendor if Fwy RPM's are a significant portion of your cars use. If its just a street or back roads car than 4:xx are fun.
Several options. 5-6 speed manual, OD automatic or GV for 1:1 transmissions
As said, all personal preference. For the OP, 3.55:1, or 3.73:1, would be good.
Just remember, the higher the numerical ratios are, the quicker the accell, and less time in the gear selected.
If your planning on a lightweight flywheel and clutch then 4:10 for M20 and 4:56 for M21 or 22. Me, I have no problem with 3200 to 3500 rpm for extended periods on occasional road trips but, some guys hate it in which case you just drive slower.
Currently running M20 with 3:73 with a lightweight flywheel/clutch. It's works and is fun but 4:10 would be better around town.
My old config was an M20 with a 3.73. It got me out of the hole quick. Fairly evenly spaced gearing until the shift from 3rd to 4th. Noticeable RPM drop during that shift.
Current is a M22 with the same rear at 3.73. Don’t get out of the hole as quick, and if I made a hard launch that actually hooked up, there’s going to be some breakage. Most likely in the shearing of teeth of first gear. For me, it will be a solid car again with a 4.30 in the rear. One change offsets the other.
The M20 took 6 grand launches with a 1.59 60 foot time for years.
This video will give you an idea of the old config. 1/8th mile pass. Through top of third and just into 4th at end of eighth. It’s the sound....and the levitating keychain. Heh.
Just my .02 I have a M20 with the factory 3.08 gears sitting behind a mildly built 350 and I love it. It's not a race car and I didnt intend on making it one. It's fun to drive I can just cruise around and still has plenty of snap to get you in trouble if you want it. My 68 coupe was left to me after my father passed away and I just wanted to enjoy the car without beating it up.
I've read in a couple of different places that an ideal combination is around 10 when you multiply your first gear ratio times your rear end gear ratio. That being said (previously), it's all subjective. Your tire diameter also affects things.
I have a T56 with 4:10 in another car with a 27" rear tire
1 2.66
2 1.78
3 1.30
4 1.00
5 0.74
6 0.50
IMHO a perfect combo. At 80 mph in 6th I am at 19xx RPM. With the 2.66 1st gear it is great and definitely not a immediate 1-2 shift.
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