Tremec or Toploader?

bishop1911

New Member
Apr 11, 2005
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I want to get my transmission and driveline setup soon, but the more I research, the more I am unsure of what to do. I initially wanted to use a toploader, but then decided it might be better to go with a tremec 600 due to going to shows and traveling on the highway and not wanting to run the car in high rev's for hours at a time. Then as I look into tremec's, I am hearing that I may have to or will have to modify the tranny hump. I really do not want to have to modify the transmission hump at all. It is primed and other bodywork is being done. I would like to go with the tremec, but don't want to modify. I asked dark horse about this and they said the top of the tremec is wider that the toploader. Is this true and if so by how much? I would like to use the tremec, but don't want to modify my car by cutting it. If someone can give any feedback that has maybe used the tremec or can give me measuerments of the tremec and toploader, that would be very helpful. I have looked at the kiesler "no mod", but it even says it may still require cutting of the hump. I am looking for a good answer here, but I have a 390 FE and will be pushing over 400HP, so I want something that can handle that. Thanks.

Jon
 
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You could still go with a Toploader and use 3.25 or 3.50 gears and keep the revs down. With a 26" tire, you'd only turn 2520 @ 60 mph, 2940 @70. A 390's got plenty of torque to still move the car in the 1/4 mile with 3.25's. My 67 ran low 14's with a pegleg 3.00 rear and a stock 390.
 
I have two tremecs in operation, love them, tko 6oo and tko 500. Opt for the .82 final though as the .67 bogs down too much unless you like around 90. I run 370s in the rear. Just a wonderful setup. One is behind a modular 5.4 in a 67 and the other behind a 302 in a 68. I have bought another for a 65. So far I've not cut the hump except for the 5.4 install. Had to trim the side just a little for the shifter. I use a "Hurst" shifter handle and 5 speed knob. This looks kinda cool and keeps the vintage look. Hope someone will chime in on the 390 fitment. It will take the hp and not even grunt. Good luck either way.
 
If you are driving for "hours at a time", I would get an od transmission. I have a 3.08 gear and 25.7" tire and it is ok, but much over 40 miles gets old. I am looking at a 2.73 if I do the Power Tour.
 
If you do hours at a time of highway driving I would recommend the Tremec. I have a toploader with 3.50s which I switched to from 4.11s but still get revs around 27-2800 rpm @ 65mph. I have been thinking about switching to a T-5 in the future for this reason. If you are at that point now I would go with the Tremec and mod your hump, it will be worth it. Good luck!
 
I think there is a drop bracket assembly which allows you to install a tko into a mustang without cutting the tunnel.
This puts your motor on an angle, as well may affect the u-joint angle a little.

I have a head on picture of a mustange with (I believe) a tko. The flywheel appears to be inches from the ground (lower than the collector flanges on the headers and the entire exhaust system) I assume this is what the lowering bracket might do.
It looks dangerously low to me.

Makes me re-think about what I want to do with a tranny again.
 
Transmission

I just spoke with the tech at Dark horse about all of this. He said there is almost no way of getting this thing in with no out of the ordinary angles if you don't modify the hump. He said that you have to angle the pinion so that the engine would be leaning back a bit, which as stated will add more stress to u joints. Not to mention that I can't believe that would be good for the engine. Other than that, he said there are a bunch of little fixes to get it accomplished, such as a bracket in place of the crossmember which gives another inch. A little of this, a little of that....but in the end, it seems like it wouldn't be "right" I know I don't want to cut the hump open on this car. Just don't want to get into that. Also, the T-5 will fit, but is not nearly as strong he said. Don't want to do that either. Unless there is another option, maybe I will end up going toploader after all. I really would like to go with 5 speed, but I am not about to start doing all kinds of crazy things to "make" it work and cause other issues down the road. I would rather get a 4 speed and maybe an extra pumpkin and switch that out if I feel the need. I am still going to research before I make a final decision, so if others with a 390 have accomplished the tremec install without modifying the hump and not had to do all other kinds of crazy things, I would love to hear about it. This would still be the preferred option, but it just may not happen. Thanks guys.

Jon
 
The extra angle on the engine wouldn't bother it. I'd be more concerned with the stress on the output shaft on the transmission. What gears are in the rear now? I swapped the chunk in my 68 Merc Monterey from 2.75 to 3.70 and the difference on the highway wasn't a problem for me. Sometimes, depending on where the powerband is in the engine, letting it rev more on the highway can be a good thing but this too, depends on how far you want to drive it
 
Gears

Right now I have 3.73's in the back. The guy building the engine for me is a real top notch builder or classic motors, and he was telling me that the "rev band" as you mentioned for this car would be up in the 3K - 3300 RPM range. He said this would be the "clean" run zone for this car. Maybe this wouldn't be an issue. I just don't want to feel like I am pushing the car at 65 - 70 on the highway, although I don't anticipate a lot of highway driving. I certainly would like to have that 5th gear, but I am not about to cut up an all original floorpan which had no rust and is already primed to accomodate. I can just buy another set of gears. Other suggestions? And if toploader is the way I need to go, suggestions on toploader tranny's and bells?? Thanks.

Jon
 
More on the Tremec topic

I'm reviving this old thread because the previous discussion is relevant, but doesn't need to be re-hashed.

If you participated in this thread originally, you may recall that there really weren't any solutions given to resolve the requisite drive line angle when installing a Tremec tranny. It's not as bad on the 67-up cars as the engine sits a little lower in the car, and I will limit my discussion to the latter cars.

My problem is that because the engine sits at such a steep angle (about 7 degrees), my High dollar CUSTOM headers contacted the passenger side frame rail... just a little, but enough to rub the ceramic coating off, and my AC compressor pulley is riding a little high (can't tell if it will foul the hood yet though). If the engine angle were the stock 4 degrees (as measured on a stock intake) both would have ample clearance. I did a little clearancing on the frame rail with a 3lb sledge while the engine was out, so that problem is resolved at any rate, but I decided to see exactly what was fouling the tranny when I attempted to get close to the stock driveline angle. To my surprise, the passenger side had ample clearance everywhere. On the driver side however, the front inspection plate (optional shifter location) hits the front of the tunnel longitudinaly while the mid inspection plate (another optional shifter location) still has about 3/8" clearance even though it sits under the floorpan brace. At this point, the engine is sitting at 5 degrees down in back, which is close enough to stock that I would leave it there. To leave it at this angle and yet keep from fouling the front opening, I plan to move the outboard edge of the front opening in about 3/4" and mill the flange down about 1/8" all around. Then I'll trim the cover down to fit and drill new holes to fit the new smaller opening.

I'd also like to install the new TKO-600 gear set with the 2.87 1st gear. D&D Performance will sell everything for the swap for $995.

So here's my question: how do I remove the front aluminum cover so I can have it machined? After removing all the bolts, the 3 shift rails need to come out, but before I just start ripping things apart, I'd like to know what is the least amount of tear down required to get the cast cover off?

(I realize this was long, and thanks to anyone who reads it all the way thru!)