[PldBryan]

Looking for some opinions out here. The more research I do, the more unsure I become.

Currently I am replacing my mild 327 with a fairly well built 383. My car currently runs a M20 wide ratio Muncie.

When I started the project I just assumed that I would swap out the M20 and probably go to a M22. As I started to do more research, it seems that there are a lot of guys out there running these behind 400-450hp motors.

I know it all depends on intended use, this is a street car that I will likely take to the track once or twice to see what it can do. BUT, because I only put a few hundred miles on it a year, I like to have as much fun with it as possible and that means that it gets jumped on pretty hard off and on.

Likely it will never have slicks on it but i do not want to have to even think about the tranny whenever I do want to hammer on it a bit.

M22 looks to be about $2K and I have it for the trans but could definitely find some very nice other additions for the car with $2K if I dont really need to update the tranny.

Love to hear your opinions on the M20 living behind up to 450hp.

I will post up some pics of the motor swap as I get into it more as well. After that comes the new 9" setup for the rear.

 

[1quik69]

M20's were put behind BB cars from the factory. I wouldn't see any problem with your 383.

 

[jdoddy]

I run one with my 383.at least that much hp.street use only though,373 gear does good around town and on back roads.3400 rpms at 70 on interstate.

 

[chevy2much]

You will be fine with that setup in my opinion. Besides if you haven't broke it then why replace it.

 

[77-427-5sp]

i loved the one i had they are made cars without much gear at one time i had 235 60 -14 and 4:56 gears very bad combo for a m20 never used gears 1 and 2 on the street would have been perfect with 355 or higher

with big blocks the normal gear was around a 3.08 i think with a m20

after doing this 5 speed i think i would have just kept the m20 and put in 3.23 , but i sold it for 600 and bought the tko for 1500

i told the guy it was a m20 ,but he thinks he bought a m22 and got a great deal on it ,

 

[the FLYER]

before i spent a dime upgrading from an M20 to an M22 i'd go with an OD tranny... if the OD isn't desired then i'd just stick with the M20.



but personally the 5spd OD trans in my car is one of the best additions i could've ever made... calms down a HP engine in OD gear making it freeway/cruise friendly but yet 1st-4th (especially 1st/2nd) the car is a rocket ship...

i'd go for an OD and get the best of both worlds. :thumbsup:

 

[Pandora's Box]

You could get GTO's with 20's or 21's right from the factory. :yes:

 

[the tree man]

If it really keeps you up at night you could sell the M20 while it's still intact for probably 700 bucks easily if it's in good shape and roll that into an M22 or 5 speed and defray some of the cost.If you grenade the M20,which you shouldn't at your power level,that option is done.Sold my M20 for 700 clams and bought the Auto Gear M22.

 

[PldBryan]

Thanks for all of the input!

I heard what I was hoping to hear and feel better about sticking with the M20. I will pull the side panel and check everything out and update it as needed.

Doing this is going to allow me to do a few more things with the money as I have it down this winter.

Can not wait to get it all back together and see the difference in this 383/rearend combo!

 

[the FLYER]

i had many M21's, just a month or a few ago i offed my M20 w/Hurst in trade for a '63 wagon... they do take a beating.

i'd been saving that M20 for over 10yrs in hopes of building a Gasser... so much for that tranny.