Sam (Bones) Posted February 18, 2012 Share Posted February 18, 2012 getting ready to tear-down my M20 thought I better start looking for parts it's always easiest to ask here first Quote Link to comment Share on other sites More sharing options...
LS5 Posted February 19, 2012 Share Posted February 19, 2012 Morning Sam, I got all my stuff for the M-21 from a guy Stateside there off of Ebay, I think he goes by Mr Muncie...let me take a quick look I'll edit this after...His prices were good and hade everything I needed and all was original GM and fit perfect and was balsted and coated which save me $$ and time... Darren. Hey Sam. His name is Bruce, I spoke to him quite a few times from up here in Canada, real nice guy easy to work with and his Ebaymotors ID is Teammuncie... hope that helps as you know when I was contacting you on this set up I was haveing a heck of a time finding parts but not now... Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 19, 2012 Author Share Posted February 19, 2012 thank-you!!! Quote Link to comment Share on other sites More sharing options...
714024SP Posted February 20, 2012 Share Posted February 20, 2012 Hey Sam! These are the guys that did mine and built my 12 bolt Tru-Trac. Detroit Gear Box Quote Link to comment Share on other sites More sharing options...
KWick_70MC Posted February 20, 2012 Share Posted February 20, 2012 mrj52 (aka Tim) knows more about Muncie Transmissions than anyone I know. Quote Link to comment Share on other sites More sharing options...
LS5 Posted February 20, 2012 Share Posted February 20, 2012 mrj52 (aka Tim) knows more about Muncie Transmissions than anyone I know. Yeah Kevin, your right I forgot about Tim.. He does know a lot about these trannys...good call. Darren. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 20, 2012 Author Share Posted February 20, 2012 opened it up today, all the reverse gears are chewed-up pretty good, second gear has some marginal looking teeth on it so I'm going to replace everything, it has 98,000 miles on it Quote Link to comment Share on other sites More sharing options...
jacob Posted March 5, 2012 Share Posted March 5, 2012 hope your transmission shifts like silk Quote Link to comment Share on other sites More sharing options...
Murphy Posted March 7, 2012 Share Posted March 7, 2012 M20 question....I'm curious on which spline count is needed on a SBC350, going to convert from TH350 to M20. I'll be getting a new flywheel,of course, but which is recommended??Have found several m20's dated 68 to 71 for around $700..... Quote Link to comment Share on other sites More sharing options...
MCfan Posted March 7, 2012 Share Posted March 7, 2012 Murray, You may find the following site helpful in answering your questions: http://www.chevellestuff.com/qd/muncie.htm Apparently number cast in the tailshaft housing is the one that you need to pay attention to: 3857584 1966 - 1970 Passenger side speedometer, 27 spline 3978764 1970 - 1974 Passenger side speedometer, 32 spline This information from the site above would indicate that your '71 would have received an M20 with a tailshaft housing stamped with "39787" which would nhave a 32 tooth output spline. However it would have also received a matching U joint on the driveshaft. What you probably need to determine is what your current TH350 and drive shaft spline count is if you want to match it. If you have a 27 tooth drive shaft U joint, you will want to get and M20 stamped "3857384" on the tail housing like mine (see below). You will probably only want to consider M20s with a main case casting number of 3925661 for 1970 to 1974 production models. Also, you will obviously need to match your pressure plate splines to your input shaft splines. Note this quote from the site above: "There are 7 different input shaft possibilities on a Muncie. All 26 spline inputs came with 32 spline output shafts and all 10 spline inputs came with 27 spline output shafts." Actually, you should be able to select the best M20 available to you for the price and then match the pressure plate and drive shaft U joint to the input and output shafts, respectively. Sorry this is not a difinitive answer, but it should give you some possible options. Maybe some member that has already done this swap can give you more specific guidance. Good luck. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted March 7, 2012 Author Share Posted March 7, 2012 Murray, Actually, you should be able to select the best M20 available to you for the price and then match the pressure plate and drive shaft U joint to the input and output shafts, respectively. you'll just need the correct clutch disc and trans yolk, maybe a new drive shaft (length maybe different) Quote Link to comment Share on other sites More sharing options...
Murphy Posted March 7, 2012 Share Posted March 7, 2012 All good info Dennis, as usual! I have been reviewing Muncie documentation which is widely available, and am wondering which input would be preferred 10 spline or 26 spline? Since I am basically building from scratch......I can do what I want (with a little advice) as I'm told the drive shaft needs to be replaced anyway. Quote Link to comment Share on other sites More sharing options...
Murphy Posted March 7, 2012 Share Posted March 7, 2012 Was the 26 spline for the BB cars to due HP & torque?? Quote Link to comment Share on other sites More sharing options...
Murphy Posted March 8, 2012 Share Posted March 8, 2012 Talked with a guy today who has been rebuilding Muncie's for 30yrs, his comments were that a 26 spline input was 4 times stronger than a 10 spline input shaft. Also, the respective output spline differences made a huge difference in the overall durablility of the tranny. The advice to me was that using a higher splined shaft was definately the way to go since I'm building basically from scratch in a conversion from a TH350. Just wanted to pass along the info.......... Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted March 8, 2012 Author Share Posted March 8, 2012 unless you plan on some big power...either would be just fine for a street car, don't fall into one of my traps and over think it! Quote Link to comment Share on other sites More sharing options...
Murphy Posted March 17, 2012 Share Posted March 17, 2012 Great advice! It's too easy to over think an issue, having this site with experienced folks to bounce ideas off of is GREAT! Quote Link to comment Share on other sites More sharing options...
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