Well since the AV8 that I am collecting parts for is going to be "period close" it will have a T-5 behind the 8BA and be able to run down the 4 lanes at highway speed for hours on end when it really gets out and heads somewhere. It may not have the gear whine that the 3 speed would have nor will I have to come to a full stop to put it in first gear at a stop light but it will damned well suit my needs and the flattie will most likely be pretty happy after spending the past 30 or so years in a Jeep wagon. I think that a guy has to consider what he is actually going to do with the car and if you are building it more to please the sensibilities of others or are you actually building it for yourself to drive and really drive. A number of the guys I see posting in favor of the 5 speed are guys on here who are pretty well known as mile makers and tend to hit the road for events hundreds if not thousands of miles from their front doors on a regular basis. I'm old enough that I drove a lot of cars with three speeds back when and a lot of cars and truck with three speeds with a non syncro first gear that always was a pain in the **** when you had to come to a full stop to put the rig in first or reverse. But that may add to your "driving experience". I think the course of action would be to find a couple of guys who had similar flathead powered cars, one with a three speed and one with a five speed and ask if you could drive each of them to see what the difference is. I'm sure each would give you a pitch for what he was running in the process.
The coming to a full stop before hitting 1st is definitely something that I'll need to get used to. I keep playing the example of being on a street heading up a hill and having to get into 1st somehow because it's bogging down in second for what ever reason.
Very good point JJ, that may be something to consider. I do live in Seattle.(lots of step hills) If you don't know, we already knocked down our biggest hills.... http://en.wikipedia.org/wiki/Denny_Regrade,_Seattle
I agree Ive owned a 89gt, 95gt,95cobra and a 01 mustang all had t-5`s except the 01 which had the 3650 ,shifting is what made the car fun and these were all daily drivers.....but if you drive hard you will brake anything once you start put`n some power behind stock transmissions
There is definitely a different experience with a T-5 than a 39 Box. My single biggest issue with a 39 Box is that it is damn weak! I don't care how tight you set it up, if you abuse it . . . you'll break it. It is not much fun hearing the 1st gear teeth peel off like a corn cob. It gets mighty inconvenient and expensive to keep replacing transmissions. Once you break a couple, then you'll start babying it . . . which makes your 'hot rod', not such a hot rod anymore. This isn't 1950, where you can pickup another trans for a couple bucks and slap it in there . . . spend $500+ a couple times, see how it feels So - you want both . . . then setup your frame, clutch and brake setup to handle either one. The T-5 or Tremec TKO takes more room than a 39 Box, needs a different mounting point (rear) and will require a different length drive shaft, torque-tube, etc.. If I was you, I'd purchase BOTH transmissions - and make it possible to swap either into the car. Yes, it will require that you think about how to support the rear of both transmissions - but it isn't that big of a deal to do so. That way - you can try both . . . or even swap between the two. Fortune Telling: My guess, you'll start with the 39 Box - either break it or get tired of the non-synchro 1st gear, then you'll put in the T-5 . . . and never go back!
My car is not a traditional Hot rod, ('48 Plymouth with a 360) but it did do about 100,000 miles with 727 torque flite that my friends "talked me into" when we built it. I tried every thing to make work the way I wanted to. Too low rear gears = fun off stop lights - no fun on the many freeways around town. To high rear gears = slow off lights = fun on freeways. Throw a converter at it, better off lights = ****s worse on the freeways. I know this thread is not discussing auto verses manual trans, but my point is this, three speeds are three speeds whether you shift yourself or automatically. I took out a "home improvement" loan back when they were fashionable and spent a big chunk of it on a TREMAC 3550 and all the attendant stuff to put it together. It trans formed every facet of my car in ways you can't believe. I could now pound this thing off lights with the best of them, bang through the gears and then jump on the freeway and cruise along leading the traffic, not holding it up in the right lane. Now subs***ute TREMAC for T-5 and your zeroing in on what I'm talking about. Putting an overdrive trans in my car allowed me to be able to stay in a usable torque band through the gears, and then transformed the car into something I could jump into and drive three or four thousand miles and not think twice about. Would I consider building your car without a T5? Hell no, especially not with a flathead. I f the non-traditional aspect of the T5 bugs you, when somebody crouches down to look underneath and starts to whine, give them a good swift kick in the rear!
Mine has a 8ba flattie with '36 3 speed ****** and 4:11 torque tube bajo rear. Drive it on the highway for roadtrips all the time. Its an absolute time warp. Love it! Let the modern cars blow on by. I'm never in a rush driving my hot rods.