Chris mathiesen Posted September 8, 2014 Report Posted September 8, 2014 I am currently looking for transmission conversion options for my 1946 plymouth p15 club coupe. I am currently running the stock flathead six. I originally wanted a late model automatic overdrive transmission. I keep hearing there will be a reduction in horsepower. I have seen a few people using the t-5 transmission conversion. Does anyone have any REAL experience with the t-5 transmission conversion? I am open to other transmission swap options as well. My goal is to reach freeway speed of 65 to 70mph. Any guidance would be appreciated. Thanks! Quote
Don Coatney Posted September 8, 2014 Report Posted September 8, 2014 I am not sure what you mean by REAL experience??? Can you expand that a bit? Quote
TodFitch Posted September 8, 2014 Report Posted September 8, 2014 . . . My goal is to reach freeway speed of 65 to 70mph. Any guidance would be appreciated. . . Given a 4.11 or taller rear end ratio and stock size or larger diameter tires, you should be able to cruise at 65 in a stock Plymouth from 1933 up including your car. That is assuming, of course, that everything is in good repair. However driving 60, 65 or 70 in Los Angeles freeway traffic without a lot better braking than my '33 has is not something I would look forward to. If you are insistent on installing a T5 then I think Don can give you "REAL experience" as he has had a T5 in his car for a number of years and many thousands of miles now. Quote
Don Coatney Posted September 8, 2014 Report Posted September 8, 2014 Follow this link and look at all 147 photos. http://smg.photobucket.com/user/DonCoatney/library/T-5?sort=3&page=1 I did it my way without the benefit of a "kit". I understand there are now kits available but I do not have any information about them. Google "T-5" and learn the differences between a World Class and a Non World Class T-5 and decide what is best for you. Use your tire size, differential ratio, and T-5 final ratio to calculate your engine RPM's at any given speed and choose what is right for you. If you want to go this route there is a lot of homework to do before you spin the first wrench. What will you do for a driveshaft? What will you do for an emergency brake? And as Tod said what will you do to improve the braking system on your car? Quote
greg g Posted September 8, 2014 Report Posted September 8, 2014 I just drove my 46 to and from the national PoC meet about 375 miles each way. My car has the 4.11 rear end and we traveled along quite nicely at the 100 kph speed limit from Sarnia to Niagara falls. Might have even gone hyper legal a couple times when flow called for it. What is the basis of your hesitency to drive you car at 60? Most folks will answer it doesn't sound right. How is it supposed to sound, like a Lexus ideling along with 3 inches of insulation between you and the business parts? Quote
TodFitch Posted September 8, 2014 Report Posted September 8, 2014 I just drove my 46 to and from the national PoC meet about 375 miles each way. My car has the 4.11 rear end and we traveled along quite nicely at the 100 kph speed limit from Sarnia to Niagara falls. Might have even gone hyper legal a couple times when flow called for it. What is the basis of your hesitency to drive you car at 60? Most folks will answer it doesn't sound right. How is it supposed to sound, like a Lexus ideling along with 3 inches of insulation between you and the business parts? +1 on Greg's post. I guess I should have mentioned this in my first post: Coming back from the Plymouth Owners Club meet in Tucson last year, I ran between 60 and 65 MPH (trying for 62 or 63) most of the way from Tucson to the Bay Area a distance of about 800 miles. My '33 has a 4.375 rear end with tires that are very close to the same mounted diameter as used on the '46 to '48 Plymouths. If I'd had a 4.11 rear end instead that same engine RPM would have been between 65 and 70 MPH. Basically your car could have done 65 all day when it was new. And still can if it is in good mechanical shape. But it will not sound like a modern car when it is doing it. Quote
Robert Horne Posted September 9, 2014 Report Posted September 9, 2014 I installed a TK5 1983 to 1997 Ford Ranger 5 speed on to my 218 a few years ago. It was an easy install, and has worked very well. I used a 3.73 Ranger rear, since the 3.9 was too low geared. 1st gear is a little low, which has been great for starting off in hilly areas. 4th gear is good for secondary roads, 35mph, and 45 mph, and 5th gear is very good for over 45mph....... There is tread on here, "5 speed, not T5", for more info............... Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.