Help!Close or Wide Ratio 4-Speed Tranny for racing?
 

I always thought the Muncie Close ratio 4-speed trannys were better for takeoff but I heard the other night on barrett jackson auction they said they were worse and a wide ratio had a lower 1st gear for better takeoff off the line.Is this true and what are the advantages of the close ratio if that is true.I always thought people ordered cars with a close ratio to go drag racing.Did the close ratio cost more when you ordered a new car over the muncie wide ratio?Thanks

Wide Ratio for sure, run as much first gear as you can. A 2.20 first gear for drag racing is a waste. Car will always bog, or blow the tires away. have to leave on the valve spring to make it work. The only good thing about the close ratio is less drop on the shift keeping the engine in its power range. You leave more on the starting line without a good launch.

Close or wide depends on your rear gear. You wouldn't want a close ratio with a 2.56 rear and you wouldn't want a wide ratio with a 4.33.

Wide ratio is better for the street and racing. Pontiacs have a wide torque curve and you don't need closely spaced gears.

Close ratio were used if you ran really deep rear gears, like 4.33+. Also, close ratio has less RPM drop between 3rd and 4th gear, which is good for road race.

From the factory, wide ratios usually came in cars with lower numerically rear gear ratios, and close ratios came in higher numerical rear gear ratios.

If you have the traction, a wide ratio with a 3.90, 4.10 or 4.33 rear gear is a great combination. Depends on engine size/power, car weight & tire size.

if you do the math, the ratios first through third are the same, close ratio Muncie VS wide ratio, just the drop and wide ratio is between 3rd and 4th.
First gear ratio with a wide ratio trans and 3.55s is the same as the close ratio with 4.10s.

Most all out drag racing 4 speeds have a first gear ratio around 3:1, but they use clutch technology to slip slightly on gear changes

Thanks for all you replies.Very helpful.

Both wide and close have the same 4th gear dont they?

yes both are one to one

A wide ratio is going to have a weaker first gear but otherwise will make life easier for the rest of your drivetrain.

Thanks for everyones help on this

For any kind of RACING with a strong level of torque, neither a stock m20 or M21 is going to hold up long. The goobers announcing BJ need to clue into to properly announcing the cars. Documented born with original engine, transmission, rear?

What car /engine/clutch/rear gear are you running? My M20 has held up great, no problems so far on slicks or street tire. I have run a variety of clutches and flywheels, heavy billet with dual disk to center force dual friction and aluminum, my current combo.

400 ram air IV with centerforce and currently 3:55 and close ratio Muncie but want to change to 3:90 or 4:10 since I drive it on street also.I was wondering if anyone knew if you could get a close or wide ratio muncie with a ram air IV from the factory since they came with the 3:90 gear and 4:33 was the optional gear.My GTO didnt come with this ram air IV motor it has now.Hate to change the tranny to a wide ratio now since the close ratio has been all rebuilt recently.Thanks

M21's and T400's were only transmissions avail with RAIV's. Engine required 3.90's or opt 4.33's along with heavy duty cooling. When roundport 455HO's were introduced, Pontiac installed M22's behind them, trying to keep warranty issues down. The M22's worked well except in a few instances. The 2.20 first gear wasn't the best in 3.31 geared 455 HO cars. Some 3.31 geared cars owners suffered burned up clutch discs in light driving. In 70's class racing, have heard of a few racers that tore up M22 after M22, until they went with Nash 4spds or converted to automatic.

Maybe doing the math when you are comparing a wide with a 3.55 and a close with a 4.10 but your statement is totally wrong when comparing transmission to transmission.

"Wide" on the early GTOs was 2.56 and "Close" (on a very very few GTOs) was a 2.20 first gear ratio.

The gear ratios were NOT the same. "first through third are the same" WRONG!

Tom V.

I just got a hold of the guy that rebuilt the tranny and he said my close ratio had a 2:20 1st gear and the wide ratios he rebuild have a 2:56 1st gear>i guess he would know what he is talking about.

If you use a wide ratio (which I think makes sense if the rear is 3.73 or less), make sure you use the one that has a 2.52 first gear. It has a 1" cluster pin versus the 15/16" on the trans with the 2.56 first gear.

Pretty easy to look up the gear ratios of 'close' and 'wide' ratio Muncie transmissions.
Wide - 2.56 or 2.52, 1.88, 1.46, 1
close - 2.20, 1.64, 1.28, 1

why don't you do the math first Mr Engineer, the actual numbers are not the same but the ratio spread from each gear to the next is the same, except for 3rd to 4th


1.88/2.52=.746 1.46/1.00=.78 for the wide ratio RPM drop each gear 1.64/2.2=.745 1.28/1.64=.78 close ratio