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Here's the thread on Muncie transmissions versus the rest of the universe.
Let me start by saying give me an M20, let me make a few mods, run it and tell me that there isnt anything sweeter for the money. They are simple, and with the right mods (big bearings, torq locks, rigid center plate) can be pretty stout.
I remain a fan.
Scorp
If you like the Muncie gear ratios and have rebuilt it correctly with the 21st century fixes, there's no problem with a Muncie for street use.
On the other hand it's the 21st century and 5 and 6 speed transmissions are available which do offer more performance. Overdrive is a great thing.
Sure overdrive is great, but adds weight, and when your driving the shit out of your car, all you need is a good 4-speed/shifter, which is where the fun is at!. In 5th, and 6th gear the air drag takes over, and then you are just cruising. NASCAR does pretty good with 4 gears.
You don't need a transmission jack to take a Muncie out either, and it can be removed/repaired, and installed in minutes, which I know has been done many times between heats at the track by some people.
Quote:
Originally Posted by Rick_L
Yes to both posts #1 & #2. The Muncie M20 is a good tranny no modifications necessary. In fact I prefer the Corvette Muncie shifter to the Hurst, just feels nice. If Muncie had an overdrive then there would be less interest on my part for a Tremec. Muncie shifter position is not conducive to the bench seat in forward position and my Nomad RPM’s were to high at highway speeds being the reasons for me to seek a Tremec. Muncie M20 and Tremec TKO 600 gear spacing is good. But I found the Muncie M21 spacing too close for normal street driving. True the rear end ratio has a lot to do with the tranny gear spacing. My preference for M20 with 3.55 gears vs the M21 with 3.73 because of the stronger multiplication in 1 st gear and a bit nicer at highway speeds.
But now that I have the Tremec with forward shift position, I’m glad I made the switch. I find the shifting smoother with less effort, excellent gear spacing and less revs and noise on the highway. But it’s not a fair comparison between two designs that are 50 years apart.
The Muncie was hard to beat, strong with a couple gear ratios. Through the years I used and ended up collecting a few: I have 2 in cars, 13 rebuilt ones on the shelf, 2 more waiting on some case machine, another 8 or 9 in parts. They are m20, m21 and m22 units. I’ll obviously never use them all, but weren’t expensive when acquired.
The last few years I’ve moved on to T56s and Tremec magnums, having a couple each in cars. I really like the close ratio magnums, with the gear spacing and the ease of shifting, and a 700ftlb rating doesn’t hurt.
I think it's hard to match internal shift rails with forks attached directly to them and just a small socket for the shift lever with an external shifter with sloppy rods that go out of adjustment as they wear. The Tremec design is far superior to any Muncie imo. If you want to cut weight, stop eating cheeseburgers. :D
Clearly if ALL you do is race you don't need an overdrive transmission. There's a lot of stuff you don't need like radios, A/C or power anything. But most guys aren't building race cars, they're building performance cars for the street that you can drive on the highway at 80 MPH and have a lot of the comforts and conveniences of a new car. That's where the overdrive transmissions and all the modern electronics really shine.
Interesting thing on weight. Sure Tremec weight is way more than Muncie. But the 50’s and 60’s cars were way lighter than the performance models today. My 65 vette is under 3000 lbs a new one is like 3600, my 68 Camaro was 2960 lbs and new Camaro is over 4200 lbs. Using a modern LS/LT and Tremec, will eat the lunch of same tri five with a big block and Muncie. So much can be gained from drive trains from the past 50 years from the heavy weight cars produced today shoved into tri fives.
I don't know what "way more" means, but I know a T56 weighs 115 pounds, a TKO weighs 105 pounds, and a muncie weighs about 85 pounds. That's only a 20-30 pound difference and if you were really concerned about weight it could easily be made up elsewhere. And like I said, a race car doesn't need overdrive. Not many of us are building race cars.Quote:
Originally Posted by Gmvette
The weight difference is partly due to engines being aluminum now, but a lot of it has to do with all the power options and safety equipment too. A 12-way power bucket seat is way heavier than a manual power bucket seat. Then you have power window motors, power door locks, better stereos with multiple speakers, sound deadening, lots more wiring and electronics, safety features, and a lot more. When you look at the difference between a '68 Camaro and a 2019 Camaro, there's no comparison when it comes to the interior comforts and options. All that stuff adds up.Quote:
My 65 vette is under 3000 lbs a new one is like 3600, my 68 Camaro was 2960 lbs and new Camaro is over 4200 lbs.
If you're building a car to race, weight matters. If you're building one to cruise and handle well on curves, it doesn't matter as much. I used to think about how much my Nomad is going to weigh, but I don't really care anymore. It's not a race car. Fretting over the weight of a street car is like fretting over gas mileage of a race car.
My 67 SS 350 with a Super T-10 and a 12 bolt with ps, pb, disk brakes &alum intake tips the scales at 3360, my 74 Z28 with 4 speed is 3750 with AC, I think new ones are about 4400.Quote:
Originally Posted by Gmvette
A twenty to twenty five percent increase in tranny weight is substantial. The size of a Tremec TKO is about the same percentage over a Muncie. I’m not sure how one compares to the other in torque capacity, efficiency and longevity. The 30 pounds added if done all over the car quickly gets you over 4200 pounds. It would just seem to me putting more power in to a street rod only to counter act it by making it overly heavy defeats the purpose. I like spirited driving as well as the next guy but weight is counter intuitive to that goal in MHO. Newer heavy cars seem to handle and perform great. But think how much more enhanced they would be with less weight. Drive trains are not over all heavy, but anti crash structures and DOT dictates puts on the pounds.
If you are trying to build a "silk purse out of a sows ear" of course weight doesn't matter. But, a portly car will never out accelerate, brake, or corner faster than a lighter one. It's like pulling a trailer behind a car when you add 1500 pounds for all the convenient gizmo's. I weigh 175 at 6'2, and a lighter driver would be faster. You really notice the weight difference in a kart, motorcycle, bicycle, walking/running, or even a horse. I don't know how I could possibly carry around even an extra 100 pounds every day. I know I could accelerate, turn, or stop faster, plus it would hurt more to fall down.
Yeah, but for 25% more weight you get 25% more gears too!! :D The T56 is a better deal because you get 50% more gears for only 35% more weight! :eek:Quote:
Originally Posted by Gmvette
It all depends on what comforts and conveniences you want. If you want PS, PB, PDL, PW, power seats, a big amp, 6 speakers, subwoofers, and A/C, you can't do it for nothing....they all add weight. Sure a lighter car will accelerate faster than a heavier car with the same HP/torque. So you either lighten the car up or increase power to improve performance....what are you willing to give up to do that? I don't understand what "overly heavy" is when you want all of those power things. All you need to do to counter them is add power if you want. My Nomad with the BBC and all that power stuff should have around 6.5-7 lb/HP and 5.5-6 lb/ft-lb of torque. That should move it along just fine. :cool:Quote:
It would just seem to me putting more power in to a street rod only to counter act it by making it overly heavy defeats the purpose. I like spirited driving as well as the next guy but weight is counter intuitive to that goal in MHO.
You can always buy a new car with the least options, and rip out the seats, A/C, stereo, and everything else that adds weight if you want a light car. That's basically what they did with the new Z/28 Camaro. It's all a tradeoff. And I'll bet the added options outweigh the DOT safety things on new cars.Quote:
Newer heavy cars seem to handle and perform great. But think how much more enhanced they would be with less weight. Drive trains are not over all heavy, but anti crash structures and DOT dictates puts on the pounds.
Bottom line is if you want a race car, build a race car. If you want a cruiser that performs well with all the comforts of a new car, build it that way. That's what I'm doing.
Total BS. All you have to do is have a higher power to weight ratio, big brakes and tires, and a great suspension. My Nomad will easily out-accelerate a sedan with a 350, out brake one with stock brakes or a tiny disc brake kit, and corner better than one with a stock suspension. You say "never"? What horseshit. LMAO!:DQuote:
Originally Posted by 55 Rescue Dog
Not really. The rule of thumb for the drag strip is 100 lb weight reduction = 0.1 sec et improvement. You won't notice unless you're running a strictly competitive class. It's just when you do that 5 or 10 times that it's noticeable.Quote:
A twenty to twenty five percent increase in tranny weight is substantial.
That's very interesting Anut. So if you take a C4 and make it a 1000 pounds heavier, put on smaller front tires than a C4, with a big motor perched on top, with the rear track narrowed, it will take a corner like a C4 Corvette? I've autcrossed my 13 cop Tahoe just last year, which is similar in size with same wheelbase as a tri5. I know how a heavy vehicle is reluctant to change directions. It did pretty good, but didn't need more power, handled good with all the computer controlled stability/ABS/traction,but most definitely needed less weight. Had new Goodyear cop tires too. As far as Muncie transmissions go, I know that would be more fun than the 4-speed auto I'll probably use on my 55 C4. You might give a little more thought into a roll cage with all the power you have.Quote:
Originally Posted by chevynut
PS...that Tahoe at 5200 portly pounds, could easily spank almost any tri-5 in an autocross, down the road, and especially across the median, unless it was a stock try-5. Certified for 149mph, and 45 mph in reverse. One thing they did to these cop trucks, for some reason was to block out disabling the stability control which ruins all the fun in the snow. The only old Chevy I've seen in the snow forever, was a couple years ago, and that was a ratted out 58 Biscayne.
Attachment 9770
Rescue dog that is a neat Tahoe. Does it have 6.2 liter, 4WD? It looks lowered, what’s the wheel size? Looks like it could be part of Trump’s escort.
It is a law of physics an object in motion tends to stay in motion. Cut that weight down and it is less pronounced. Try to change direction and the same law of physics still applies. Add in the friction as turning and you have a bigger fight against weight. Same applies an object at rest tends to stay at rest, increase weight and the force to over come goes up by multiplication factors. So simply adding power to a porky (weight wise) car as chevynut suggest does not equate to the same outcome.
About the only thing in this thread I agree with because we proved it 35 years ago at Lawrence Drag strip with sand bags.Quote:
Originally Posted by Rick_L
It is 2WD PPV (police pursuit vehicle), the 4WD is an SSV. It has a 5.3 engine, 6 speed, 3.08 locking diff. They sit lower than a stock Tahoe. The Goodyear tires are a unique size 265/60-17 V-speed rated, and are still used on the new Tahoe. They are government priced at $1300 a set, plus installation which I did myself. I run Michelin x-ice winter tires on the stock cop wheels.Quote:
Originally Posted by Gmvette
At the Michigan state police car testing, I think the Tahoe could do 1G in a corner. Another fun thing with an ex-cop vehicle, is the left lane is always open, and you get to go first at the stop signs. I had a 90 9C1 Caprice ex-patrol car before which was much more fun to drive, probably because is was like 1400 pounds lighter, and it is the same wheelbase as a 55, Tahoe, Chevelle, GTO, 442, Impala SS, etc. I have had many of them, and loved them. The 96 Impala SS was the best GM ever built on that 116 inch platform, except that it swelled to a porky 4200 lbs. They stopped production after that to produce the even heavier trucks everyone wanted at the Arlington, Texas plant. Sad.