Just curious...A friend told me he had a six-speed out of a 2001. Could that be put in my '71 without major distruction to the console or my pocketbook? Would I even want to do that? Another friend has a M-21, freshly rebuilt he decided not to use. What would I gain replacing the M-20 I have now? I think mine is going to need some work soon since it tends to pop out of 3rd sometimes on deceleration unless I hold it in. I can feel a thump ever so often holding it in. What would that likey be? Thanks, Dwain

longhorn294 said: Just curious...A friend told me he had a six-speed out of a 2001. Could that be put in my '71 without major distruction to the console or my pocketbook? Would I even want to do that? Another friend has a M-21, freshly rebuilt he decided not to use. What would I gain replacing the M-20 I have now? I think mine is going to need some work soon since it tends to pop out of 3rd sometimes on deceleration unless I hold it in. I can feel a thump ever so often holding it in. What would that likey be? Thanks, Dwain

depends on what your goals are..

the 6 spd is a nice upgrade.. youll need to change your rear end gears to match in all likelyhood..

here is some info i did on my transmission search.

http://www.direclynx.net/~cthulhu/corvette/trasmission_search.html

the ls1 t56 is the geared the same as the viper in the link above...

be careful when putting in a 6 spd with a lower geared rear end though you could easily reach 10000 drive shaft RPM in 6th gear (5000 engine rpm).. you must make sure the drive shaft you use is properly balanced for these speeds.

i would not recommend going from the wide range m-20 to the close range m-21 in a street vehicle.. if you want to drag race your car and have a 3.70,4.11, or 4.56 rear end then I say go with the m-21..

Any idea as to what is making my m-20 pop out of third on deceleration? And the cost to fix?

well.. it could be as minor as shifter alignment.

could be a broken or bent tooth on the gear.

if it isnt shifter alignment..

then youre going to pull the trans.. might as well rebuild it..

and if it is a gear... they are expensive..

rebuilding my m-21 (which needs new gears..) would cost about 1700$ converting to 6 spd is 2300 (including new transmission)

im springing for the extra 600$ for better gearing and more enjoyable driving.

So, a m-21 tranny rebuilt for $500 doesn't sound like a good idea? I plan on changing the engine to something better than the original 270hp in it now. Why exactly would I not want to go to the m-21? Pardon my ignunce. Axe yo momma how she durrin.

because the first gear ration in an m-21 is 2.20:1

compared to 2.52 or 2.56 in the m-20..

lets assume you have a 3.08 gear ratio..

your drive ratio in first gear is going to be 2.2 * 3.08 = 6.776 .. this launch ratio sucks..

you dont have anywhere near enough power to have a good launch with this gearing.

just for the sake of argument.. lets assume you have a 3.73 rear end.

you launch gearing would be 8.2 ... which is still too low for a low torque engine.

desirable is between 9 and 11.. 4.11 gearing gets you to 9.04

this will give you great bottom end acceleration but your top end will be horrid 3700 rpm to do 70 mph in 4th gear.

look at my transmission search link and look at this tranmission calculator below.

http://www.5speedtransmission.com/gear_calculator.html

|UPDATED|10/7/2004 6:57:17 PM (AZT)|/UPDATED|

I actually have a six speed in my '78 and I'm lovin it. I would stay away from the LS1 T56(Six Speed)... I don't even know how you'd go about doing that. But! The LT1 six speed is a relatively simple swap. The bellhousing bolts right up and centerforce makes a flywheel, part number 700107 to use the LT1 camaro clutch with our two piece rear main seal engines. Sweet deal! But... you would have to chew up your old console, so if you want a stock look, forget about it.

|UPDATED|10/10/2004 4:31:05 PM (AZT)|/UPDATED|

my six speed shifter comes up right where its supposed to.I just modifyed the shifter