toploader differences
 

Does it make much difference which toploader I use for a Kirkham build with 427? I am a little confused about big in big out splines vrs. small ect..I went to Kee's site and I have the Tag ID list however is one better or nessesary over the other? thanks;chuck

It would be the same rules with any tranny Chuck. The more splines you have on the input and output shafts the better. More splines = more area to take all the stress. It all depends on what kind of applications you're planning on using. I've never really messed with a toploader, but I know the differences between Tremec trannies. I think the regular 3650's and 3550's have 10 spline input shafts, while the TKO's have 26 splines. The TKO of course is rated for about 75-100 lb-ft more...

If you are running the 427 FE, the correct transmission is a "big in", "big out". Those are 1 3/8" input/output with a 31 spline tail shaft. Originally, the close ratio was only available in the 427/428 ; however, David Kee does make a wide ratio "big in, big out". You also might want to ask him about the special white stripe Toploader Sebring Box which was a very rare transmission built by Ford for racing only. It was never available to the public as an RPO item.

The "small in, small out" (1 1/6") was available for all engines from the 200 cid six cylinder up to the 390 cid. Those could be ordered in either wide or close ratio from Ford.

Originally (I think) the 427 Cobras used the longer 27" Toploader but switched to the 24" inch at some point.

David Kee is the man to talk to if you are considering a Toploader. Best on the planet.

That is where it gets confusing;on davids web site he shows the 1965 AC cobra as using a 28 spline unit as well as the 65 427 Galaxie;most 428 and 429's used a 31 spline unit,so it seems the small output was original to 427 cobra's. chuck

Chuck:

For your Kirkham, use a 1 3/16 input / 31 spline output 24" Toploader. Ratio will depend on purpose and the diff ratio you are running. In my Kirkham I am running a close ratio box with my 3:54 rear end and am very pleased..

The 24" is a short tailshaft with the shifter assembly at the end of the housing. This tailshaft housing employs an inline trans mounting pad...there is no cast in monting flange used. There is no option here... if you have a Kirkham and you are using a toploader, that's what you use.

Cal's right. Call Dave Kee and he will know exactly what you need. If you choose another source, just make sure it meets the above characteristics before you put any money down.

Bud:JEKYLHYDE :JEKYLHYDE :JEKYLHYDE

With all due respect to Cal and Bud (actually I am surprised I caught you two) but ...

The original 427 Cobras used a Big in and a Small out (not the real small out that was recalled in the late 64 and early 65 cars) with a 1965 Mustang tailhousing. Please note that the Mustang tailhousing has to be bored out to put in the large output shaft.
I believe the big output shaft did not come out until 1968 with the 428 CJ Mustang.

For a 427 car you will need a Big Input. You do not need the big out put shaft unless you plan on drag racing the car. If you go drag racing please let us know which parts you break. ;)

For a street car I would recomend a wide ratio trans.
For track use I would recomend a close ratio trans.
The wide ratio trans is not original but boy is it nice on the street.

Tom, thanks for clearing that up. I would have said the same thing Cal said--thought the output for CR was 31 too. Now, I remember, the big "out" didn't come till later, as you say.

One other point to note: I have a CR and 3.54 and I really like the fact that you can stay in first so long, but if I could start again, I would do a 3.31 and WR for the lower cruising rpm.

Hi, Thomas!

I never feel "caught"...just "enlightened" ;-)

From an "authenticity" or "accuracy" standpoint, you are completely correct. But realistically, considering one will most likely have a trans purpose built, using a small output would be like rejecting ARP internal engine fasteners because they were not used on the originals....

I agree with you on the ratios, though. But I have no complaints.

Debating this stuff with you is like debating Einstein on relativity...or Dr Ruth on sex.....:3DSMILE:

Jim:JEKYLHYDE

I'm running a David Kee Toploader, big input/big output, WR, 3.31 rear gears. I'm very happy with this combination for the street.
Jeff

Thanks, Tom. I stand corrected on that. The 31 spline wasn't until later. Besides mixing my metaphors, I am guilty of mixing my dates up.

3.31, Kee--big in/big out...a perfect recipe that shouldn't be messed with.

Great for the street and cruising, and though I have yet to try it, it just feels right for autocross--where you don't want to be shifting a lot.

You want the tranny with a 24" overall case length, or a 14" tail housing length with the shifter mount in the mid or end part of the tail housing. Galaxy's and later fairlanes used the longer tranny, 27" long, with a 17" tailshaft.

If you are going with a 3.54 rear, you will want a close ratio tranny. If you go with a 3.07 rear, and use a wide ratio tranny, you will have the same first gear overall multiplication, for the same launch, but now have a little better cruising rpms. 2nd gear, the 2nd gear from the back will have 28 teeth if the tranny is a close ratio, and 31 teeth if it is a close ratio. You can't always go by the tag, as many trannys have already been rebuilt, using mismatched parts, and the tag doesn't always guarentee what's inside. When inspecting a tranny, the gears should gradually get smaller starting from the back of the tranny going forward. If not, then the tranny maybe an overdrive toploader from the 70's, and is worth about $50, as you will need to replace many parts to change it into a wide/close ratio.

You can use a small in / small out tranny, as used in small blocks and 390's. Just make sure the output shaft is 28 spline, and not the 25 spline, otherwise you will have to replace the mainshaft as well. I know builders who put these behind 427's and don't have any problems. You can easily convert a small input to a large input by replacing the input gear and front bearing retainer, and keep the small output just like the original 427 cobra's. I believe the small input shaft was the weakest link in the small spline toploader. Boring out the tailshaft to change a small output to a large out is going to cost, including the cost of buying a large output mainshaft.

You will pay more for the big in / big out 24" tranny core, usually hundred's more. Therefore, it may be cheapest to buy a small in ' out tranny core, and rebuild it to a big in / small out tranny. But, if you want the big in / out tranny, you will spend more money.

Regarding rebuilding a toploader, replace 2nd gear no matter what. If you reuse all other parts, you've spent about $250. Replacing to a bigger input is another $200. Any gear chipped or with surface rust needs to be replaced, as the gears are case hardened. If there is any pitting on the inner bearing surface in the cluster gear, it needs to be replaced. Prices add up quickly. Don't forget the shifter. Expect about $400 more for this.

When you buy a rebuilt tranny, you have no idea to what extreme the rebuilder went to. People will reuse rusty gears, or file down the worn syncro teeth and reuse the gear instead of replacing it. The great deal you think are getting with a low priced rebuilt rtanny may not be as great of a deal for what you are getting.


I've met and bought alot of parts from David Kee, and he is great to deal with. You won't get taken, whether you buy parts or a tranny. www.4speedtoploaders.com

I've also bought parts and a shifter from Mark at www.toploaderheaven.com , and he is excellent to deal with as well. Dan William's shifter has a cast aluminum adapter block that repositions the shifter correct for a 427 car. Mark builds a shifter that instead of bolting the adapter to repositon the shifter like Dan William's, his shifter has a welded bracket that repositions the shifter. It can't come loose.

The cost difference between the small in/small out and the big in/ big out is negligible. If you find a core, it is probably less than $100 dollars to build it as a big in/big out. The only difference is in the input ($10 difference) front bearing retainer (minimal), and the mainshaft ($10). You will need $30 to bore out the tail to accept the 31 spline and that is about it. The gears and synchros are all the same for either tranny.

As Anthony so correctly indicated, never assemble these transmissions with used parts.