I am putting a '27 T coupe together. I am will be running a 327 with 2x4 tunnel ram, and a 9" rear end. I will need to be turning some R's for it to perform. I will have to drive some 20 miles to anywhere from my house. Closest town (gas) is 19 miles away. I am building it to be a light to light type car, there isn't many straight roads around here, I live in the mountains. I want it to hook up good enough to plant the tires, not just go up in smoke. But I will drive some hwy's at around 55mph or so, to get there. I am not sure as what to run for rear end gears, I guess it matters on the transmission also. I know, put a 4spd in that sucker! I had all the 4spd stuff for it, but I have a bad knee, and there just isn't much room for three pedals. So I sold it all, so auto it is now. I have been told to run a 700r4, then I could run 411 or + gears, and have a good take off, and have the overdrive for the highways. I have also been told to run a 350 turbo, and then run high 3's gears, and I won't have a problem with the highway. I would like some input, as to what you think, so I can make up my mind, as to which way to go. Thanks, Pat
also, the guys telling you that you need overdrive, are not running tunnel rams, are they? think about it.
I've had everything from 2.47 to 4.11 gears in my Chevy II with a blown 427, and a TH400. now it also has a gear vendor overdrive in it, with 3.89 gears. But I also get out on the highway at 70 mph quite a bit. I have taken it on a trip over 1000 miles long, with 4.11s. Before I got the overdrive.
Damn, you pulled your post. I'm turning over 2800 at 65 with 3.80 gears and 29 1/2" tires. With the taller tires and higher gear I'm close to ya George, getting there takes me a little longer though I bet. Forgot to mention the th350.
I know I'm going down in flames for this, but think about a 2004R. Doesn't have the real short first gear of a 700, but it's a smaller lighter unit. And that will let you run a little more gear for the induction system. They can be built to hold a fair amount of hp and in a small light car will be fine. I replaced a pg in an OT car, and while I had to change the trans mount, I think the driveshaft was ok after a yoke change.
whenever this subject comes up, guys start shoveling the bullshit with excavators, I decided to just skip it this time.
It's not the math...it's just that so many of us forgot the joy of hearing the motor singing when we're heading down the highway.
You might need to unpack that answer for him, although he already answered his own questioning in his first post.
T200-4R. Better than either the T-350 or much better than the T700-R4. I had a T700-R4 in my 67 Chevy II...never again will I own one of those damn things..! Horrible gear ratio's. The T200-4R - Lighter, smaller, better gear ratios, similar cost to build, and best of all, will hold the same (or better) horsepower. The first three gears will hold over 1000hp with the right builder. Mike
28" tires 3.50 gear 2530 rpm @ 60 mph light car even with a tunnel ram killing low speed torque should be a handful.
If you want a handful, put a blower on it, and shorten the wheelbase. but make sure to run bias ply tires.
Pat, Glad to hear that you folks made it home ok, enjoyed the visit yesterday. You know we did talk a little about a tranny choice for your little T bone. I also am going to go out on a limb and say IN MY EXPERIANCE the 700r4 is just a real bad choice for you and that car, or for most cars as far as I am concerned. The reason is the gearing of the 700r4 tranny. The big jump from 1st gear at 3.06 to 2nd gear at 1.62 is huge in a street car no matter what rear end gear your are using. Compare that to oh lets say a wide ratio Muncie 4 speed in the early 4 speed M20 I think years 63-65 was 2.56 1st gear and a 1.191 2nd gear in 66 Muncie went to a 2.52 1st to a 1.88 2nd gear in the M20. In the close ratio Muncie's I believe all of them were geared the same from 1963-1974 and it was a 2.20 1st gear and a 1.64 2nd gear. If you compare the two just as comparison ( as I know you are not considering a manual transmission) in the 700r4 the jump from 1st to 2nd is similar to a 4 speed and going from 1st to 3rd. This just not work well for a street car like you are building. Add to that the 35% overdrive and your two 4's and a tunnel ram and I think you are making a big mistake in the streetablity of your car. What I would do is run probably in my case a TH400 and a gear like a 3.25 or maybe a 3.50 and then pick a tire that gave me the best all around use. The TH 400 has a 1st gear of 2.48 and a 2nd gear of 1.52 much better in the everyday real world. Even a TH350 which also would not be a bad choice and it does take a little less horse power to run than the TH350 gives you ratio's of 1st gear 2.52 and 2nd gear of 1.52. Either of these would serve you well I believe, much better than a 700r4 in my opinion.
327 would be fine with a TH350. With a big block, I'd want a TH400. If you had a bellybutton 350 single 4bbl engine, then you'd want one of those plush modern overdrive automatics. But you don't...you have a fire breathing hot rod motor, so put an appropriate trans behind it. oh...you want some stall speed, too. 3000 would be nice
I agree. That's the way for the o/p to save himself a lot of grief. However, we're not sure how far he's going to go once he gases up. Also, dare I mention torque converter?
Tall tires make the rear gears seem numerically lower. That will bring the RPM's down. Adding an overdrive will bring the RPM's down even more. These are exactly two things that you do not want with a tunnel ram. They are already not well known for their ability to produce power at lower RPM's. Lower them even more and your port velocity will be so low that the carburetors may have trouble metering fuel. If you insist on running a tunnel ram with 2-4's, you will need to keep the RPM's UP, not down. And yeah, you won't be going far between fill-ups.
Sounds like an overdrive for your use is a waste of money. the 700 r is like a turbo 400 with overdrive. You can have your 200. Every body has an opinion just like belly buttons.
Run the 200 and get 4.56s. Bad ass in the low gears and enough revs on the highway to keep that tunnel ram working worth a damn. The TH350 is your easy answer with 3.90s or 4.11s. Tire diameter will play a big role here too, post it up.
I will be back on later, I have to have the wife at the hospital for surgery in 45 min. I have 29" tires. I have 2- 700r4 trannies now. But that does not mean I won't get a T350. In fact I was looking for some on line, to see what it would cost to buy one. I like what your all saying. I always used a T350 or 400 in the past.. This would have been my 1st 700r4 in a hot rod. Hombre, I am glad to hear from you. You are the reason I'm looking to change my thoughts of the 700r4. I listen to everything you said. It's 4:13am I must get her there, 48 miles away by 5:00, mountain roads! Thanks, Pat
When I built the car in my Avatar, I put a 200-4R out of a Monte Carlo SS in it and a 3.73 4 pin 9". Held up BEAUTIFULLY. I'm putting the same trans behind the 289 in my Sky Hawk with 3.92 rear. MUCH better gear spread...especially nice first gear, and the OD is .67...
Tunnel rams are for higher RPM application.... trying to knock the RPM down is counter productive.... sounds like a parts mismatch situation with overdrive....
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