I have a 327, muncie 4 speed and 4:10 rear end. The car is fun to drive around town but get out on the highway and its just geared too low. My dilemma is, do I change the gears in the rear end to something like 3:33 or put in a 700R4 with overdrive. The rear end and Muncie are not original to the car. Any opinions?

 

I hear what you're saying, as I have 4.10's as well with a TH350. My plan is to go with an overdrive, since I don't want to give up the terrific bottom end the low gears give. On my car (with 26" tires), the .70 overdrive of the 700R4 will drop the 60 mph rpm's from the current 3,179 to 2,225. That, would be perfect.

 

Do you know if the crossmember and driveshaft will have to be changed?

 

Yes, the driveshaft and crossmember will have to be changed.

 

I believe the hump has to be enlarged--it did on my 55 when i put in a OD auto trans?change the gears to 332 or 308 if you just driving and nor racing is your easiest and best bet i think!!?

 

Changing the rear end gears would be easier and a lot cheaper. However like Camaro69 said, it would be nice to have the low gears to play with and still be able to run down the highway at a reasonable RPM.

 

Guess you have to work around how fat your wallet is. Does an overdrive trans fit your budget? I would really miss not having the 4.10's, and keeping them with having an overdrive is a no-brainer. Fwiw, as far as length and girth, a 200R4 overdrive is a direct replacement for a TH350, and your 327 isn't going to hurt it. Other than needing a different slip yoke than what your manual driveshaft has, it's a slip in fit.

 

Your 327 is not going to hurt a 200R4 that has been updated in the last 15 year. In its original stock from the 200R4 is a pretty weak trans. In most cases is was placed behind motor with less then 140 HP and GM never put extra clutchs in anything back then.

 

Early 2004R's had some weaknesses (like the 700R4 did), but were later improved.
If looking for a 2004R, try to find one of the beefier ones out of a Grand National or an 82 Vette.

 

Turns out I have a neighbor with a 700R4 that has been updated with all new heavy duty parts for $200. Cant pass that up. I'm thinking I might have a Muncie for sale pretty soon.