GregS_72

So I've never had my '72 454cu.in. on the highway and it is down to bare frame now as I restore it. The original Muncie M20 came packaged with the car but needs a rebuild, so I'm at a crossroad... rebuild the Muncie or go 5speed trans with overdrive. Would be cool to have the numbers matching drive train back but also want a comfortable highway cruiser. I found a RPM calculator on the web and it says I should expect about 3000 RPM at 70mph with 3.36 gears. So those of you with the original 4 speed... what is that driving experience like? Manageable for short highway runs? Thanks!

qwank

5 speed. keep the original transmission packed away safely

DSchaefe

AGREE

My 350 with 5-Speed and 3.70 gears does 1800 rpm at around 70 mph

spedaleden

Here is proof Tremec 5 speed TKO 3.55 rearend gear.





It also save the motor, accessories and gas. Getting 22MPG with 300HP at the wheels

calif phil

My 4 speed with 3.73 sucks on the highway. Go 5 speed

Scottd

I hate my Muncie. It feels like Im shifting a dump truck. My highway RPM's are downright uncomfortable. I wish I had the money for a Tremec.

Jeff_Keryk

You want original or modern OD transmission?
The modern trans shifts better, is stronger and has the benefits of overdrive!
The original came with the car and is period correct.
I want original, but that's just me.
It's your car...

scrappy76

Theres another post going on right now talkng about what is Old School. This is where I would show my old school colors.
I am old school. nothing better than listening to my big block/side pipes cruising at 70 mph, 3000 rpms. I love the sound,vibration, I have considered changing my rear ratio, but just do not want the trade off.
I vote rebuild the 4speed, and keeping it old school.

GregS_72

sending you a PM

It's a tough one for me. I'd likely do the modern OD trans without a moment's hesitation if money were no object, but it is an expensive mod for sure. I might have to go old school on this one and pretend I don't know any better!

GregS_72

Hope you had two hands on the wheel at 100 mph!

Gordonm

Go 5 speed. I liked it so much I removed the 5 speed and went with a T56 6 speed. Plenty of gears and low cruising rpm.

Big Block Dave

If the money is in the budget, then 5 speed all the way.

If budget is of a concern, getting that muncie rebuilt will cost significantly less.

spedaleden

I do a lot of road trips, car has been to NJ, TX , KY, TN, OK, PA, IL, WI, MN. so a 5 speed made sense for me. I would of gone 6 speed if possible. I keep my 4 speed in the basement. I think overdrive in these cars is the best upgrade. If your not going 80 on the highways around here, go will cause a collision. Driving around town 4 speed was great

Remember the car is quieter on the highway with 5 speed, motor is not screaming. If you like all that noise. leave it in 4th and when you get tired of it (When the wife is with) go to 5th. Best of both worlds.

Just my 2 cents

c3_dk

What transmission do you have, and the 5th ratio?

I have a 69, 3.70, 4 speed, but bought a T5 (WC) 1988 Camaro 0.63 in 5th that I will install in the car soon.
Today @70, it have 3400rpm

gcusmano74

c3_dk

http://www.ebay.com/itm/89-CAMARO-FIREBIRD-MANUAL-BORG-WARNER-T5-5-SPEED-TRANSMISSION-GM-V8-1352-196-/321591757083?pt=Motors_Car_Truck_Parts_Accessories&hash=item4ae05cc91b&vxp=mtr

GRIZ73

I rebuilt my Muncie 4 speed and put a Gear Vendors Overdrive behind it followed by 3:55 gears. The motor is a 496 BB with 635 hp. GVO goes for $3,000.00 which is less than the 5 speed. This combination allows you overdrive in 2nd,3rd,and 4th gear. It is rock solid and more fun to drive than anything I have been in.

bj1k

The Muncie 4 speed is not a problem for me but the stock shifter has to go. That's what makes it feel like you are driving a truck. It will be replaced with a Hurst Competition Plus shifter . A world of difference in smoothness.

DSchaefe

Tremec, I don't know the 5th ratio

lopozza

3000 rpm at 70 with 3.36 gears is great for about 5 minutes, then not so much. 5 speed you can get a lower first and a higher top end. Best of everything. Save the Muncie for future generations.