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Discussion Starter #1
I have a clean 78 Black Knight, with its second 4 speed saginaw in it, but would like to replace it with a 5 speed (6 speed is out of the question with the rear end gears; however I could change them too, because it needs rebuilt). It still has the original 350 in it with 165,00 on it. And a set of bucket seats too.

I use it like a daily driver (not in winter) and a highway/local cruiser, and a truck, always hauling something, a load of this or that, or a trailer; and I am headed back to Alaska in the spring from Kentucky because I will be graduating seminary this December (3,900 mile straight shot). I drove down in 2008 (when gas prices were high), at 55mph to maintain about 17mpg for the 5,000 mile route I drove dragging my custom El Camino trailer.

Cost is important, but time is more. I own a small auto repair shop, so installation will not be a problem. I do not want to spend a bunch of time trying to find all the detailed parts from different year and model GM's to make it fit (like the t5), just something that goes together without any unnecessary tunnel/shifter location mods. I plan on looking into a new cross member, to accommodate a shorty header dual exhaust system and possibly a hydraulic clutch too.

I have called and read up on keisler's rs500 and I am a hesitant, due to their production delay (6 weeks, but forums say that's probably a crock shipping answer), and they said with the rear end gears, I will have to see if it works. Plus they lack a crossmember and clutch in their "perfect fit kit."

The Tremec TKO 500 seems to be a good option too, but do I need to do tunnel/shifter mods? American Powertrain seems to be the only one who has a complete kit for the 78 a/g body for $3195.

What are your thoughts? Both on 5 speed transmission and the vendor.http://elcaminocentral.com/images/smilies/dontknow.gif
 

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I'm sorry but I have a little bad news for you. 1. Keisler sends you a TKO500. Their crossmember sucks 2. I have had a T5 in mine and a TKO in it now and to get the proper driveline angle the tunnel has to be cut and raised.
A little good news. The shifter is not a problem as it is made into both tranny's. The T5 requires you un -bend the tabs that hold the shifter together and rotate the lever 180*.
The floor hole has to be moded a little. Once that is done you can slice up the sides of the tunnel toward the front, starting at the edges of the shifter hole and bend the hump up and weld wedge shape pieces back in the sides. It really is not too bad to do.
With a 273 rear it is going to want to cruise about 85 - 90 in 5th to be in the power band of the engine.
 

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2.73 is a bit tall for virtually any 5-spd---with the exception of the trans with a .8 OD, and then you are not getting much for your buck.

I have 3.08s in my 66 and it barely turns 1900 at near 80mph, makes 5th pretty much useless anywhere but the hiway (but I do get 25mpg with the old worn 307) TKO 600

In the 59 (TKO II) I am about 1900 at 70, and with the 454 it seems to be lugging a bit.

Virtually any Tremec trans will require floor modifications unless Keisler were willing to modify
a Tremec TKO500. I would suggest the TKO 500 for it's really low 1st gear to get that car rolling with the 2.73 rear. Car will probably want a very small cam to provide the power/torque way down low in the rpm range.

350 and 2.73, I would think you would get better fuel mileage.
I have a 454 in my 79 C-10 with a 4-spd and it will get 14mpg all day long if I can keep my foot out of the secondaries (3.08 rear)

The RS or perhaps the new trans they are working on might go in with no tunnel mods, but the Tremec will require floor mods, most likely even if you were to get one modified for your car.

(if your car is not listed, I would suggest a Keisler Perfect Fit 64-67 Chevelle trans modifications---that should put your shifter where it needs to be, but still might have a floor tunnel issue, but it would be minor.)
 
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Take a look at the Richmond 5 & 6 speeds. No tunnel mods or different bell housing required. They are available in direct drive or overdrive high gears.
 

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Discussion Starter #6
Great. Thanks for the input. So, keisler is still a good option (minus the crossmember). Does anyone know anything about their SS 700? Or should I stay with my 4 speed, because of my 2.73 rear end? Or should I swap out my rear gears for another set to get the best of all worlds with a 5 speed? If so, what ratio?
 

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Discussion Starter #7
I just started to look into richmond transmissions this morning. If there are no mods, then that maybe the way to go, unless keisler has a better option.
 

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Keisler has the RS trannys that should require no cutting----delivery time is an issue with the RS700, but I think the RS 500 is available and on their shelves (not sure)
The TKO 500 and the RS 500 are good options for your 2.73 rear since they have a pretty low 1st gear---that will get you moving.
They may also be available with the .82 overdrive that will help keep your engine from lugging on the hiway.
The .6x overdrive drops the rpm to just about be out of the torque/powerband and it may be lugging on a small grade.

Also they are working on another trans
 

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Discussion Starter #9
Bryan59EC, thanks for the info on which overdrive gear I should look at .82. Does your 66, with 3.08 have a .8 or .6? overdrive that puts you at 1900 rpms at 80mph? I have looked for gear ratio analyzers, but cannot find any that show a table with my 2.73 with a 5 speed. Sounds like I need to go with a 3.27 or so first gear to launch well and .8 OD to make it useful. Any calculators you guys know of with my 2.73 ratio? Or maybe I need to develop my own on excel.

So far all of your guys input has been better then I have been researching for a couple of months here and there. I will contact richmond (per LOCKJAW) about their 5 speed with fitment/price and keisler about their SS700 fit/shipping timing/pricing sometime today or tomorrow. The RS 500 is 6 weeks shipping delay.
 

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Discussion Starter #10
By the way, I am running 235/60R14 Cooper Cobra's at all four corners, that are 25.1" tall. I am not sure the torque curve, but the engine is the original 350 with under 200HP if I have researched correctly.
 

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Doesn't Richmond make a 5-speed with lower gearing and a 1.0:1 5-th gear (perfect for the 2.73 rear gear?).

Doug
 

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Discussion Starter #12
Just talked to a richmond tech, which was very helpful and encouraging. He said the super street 5 speed would work best, with an OD of .77, without any major modifications. The cross member has to move back 3.75 inches and down 9/16th to 1 inch to have the correct angle and having to modify the tunnel; the only mod is maybe knotching out the shifter hole about an inch.

Jeff at Keisler was honest and helpful, but not encouraging about having what I needed right now. The SS700 is available early December (to fill the orders) and goes into production in 4 weeks. Unfortunately, the wide ratio 5 speed he recommends is not available through them in any transmission until at least early 2013.

Richmond is looking better and better. They have a good chart available on their tech page. Any more suggestion, recommendations or input is welcome. I hope to have this completed by the end of the year and also hope this thread is helpful to others.
 

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.... Does your 66, with 3.08 have a .8 or .6? overdrive that puts you at 1900 rpms at 80mph?
The trans in my 59 is a .68OD

The trans in my 66 is a .64OD. I have the taller 1st gear (2.87) in the 66, and for what I use the car for, it is just fine. A taller rear gear, like the 2.56 that was available in that car, would make my first gear too tall and I would be slipping the clutch to get it rolling. (3.08 rear in my 66)

The trans in the 59 has a 3.27 first gear (3.3ish rear gear) and the 1 to 2 shift happens in a hurry. First is almost unnecessary for street use in this car.
 
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