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Toploader Identification

42K views 12 replies 7 participants last post by  gerry_007 
#1 ·
Hello,
While on my quest to replace the old FMX with a C4, I came across a toploader posted for sale. I asked the guy if he could email me the ID numbers on the transmission so I could make sure it would work with my 351 Cleveland. The numbers he sent me were as follows: O8AR 7008-D 2G309.
All the research I've done shows there should be an ID that starts with HEH or RUG, neither of which are in the codes he gave me.

Given the information I provided, does anyone know if that would work with the Cleveland, or is that for a big block? The guy speculated it was from a 302 Hypo Mach 1 Mustang, but I'd rather be sure it works before doling out the $500.

Thanks for any insight you may have.
 
#2 · (Edited)
The numbers you have are the casting for the case. Your O8AR 7008-D would actually be C8AR 7008-D. That is a case used for a 68-71 vehicle. Unfortunately, that is all that we can tell from the casting #.

The toploader cases are very universal and the same case is used for big blocks and small blocks. Also for close and wide ratio transmissions.

There should be a tag riveted to the passenger's side of the case that will have (in the above casting) a "RUG" ID. Unfortunately since these cases are universal plus being 30 years old, it could now be built in any configuration. Happens a lot and I am guilty of it too. Here is a picture of a similar case.



The tag can be seen on the LH side of the pic. Normally it is not covered in primer.

A Cleveland will use a small block toploader and you can use either a close or wide ratio.

Have the owner measure the diameter of the splined area of the input shaft. If it is 1 1/16" in diameter, then it is possibly for a small block. It could also be for a 390 since it also received the small diameter input shaft. A 427, 428 big block has a 1 3/8" diameter shaft.

If the tranny has the small input shaft ask for the length of the tip of the input shaft. If it is 1 1/4" long then you have a small block tranny. If it is only 3/4" long, then it is a 390 tranny. This shaft is not directly usable behind a small block.

Here is a cheat sheet that I drew up long ago:



The only other problem would be the tailshaft and the tailshaft housing. This is easily measured. Big cars, such as a Galaxie used a long 17" tailshaft housing. Mustangs used a 14" tailhousing. You will want to use the correct one for your vehicle as shifter location is important as is the drive shaft length. If the gentleman can give you the casting # of the tailhousing, then we can give you a better idea of what type of vehicle it came from.

Hopefully this brief intro should give you enough to get started.
 
#5 ·
Good point. A good way to tell if you have a "real" 65-73 toploader (and not the weaker 77-78 O.D. model) is to look at where the speedometer cable enters the tailhousing. The 65-73 will enter on the passenger side of the tranny. The later model will enter on the driver's side.
 
#7 ·
Hello,
The numbers he sent me were as follows: O8AR 7008-D 2G309.
That O8 is either a C8 or a D8.
If it's a C8 (1968), then it's a non-overdrive toploader based transmission.
If it's a D8 (1978), then that's bad news, as they quit making toploaders in either 1973 or 1974... and it's the weaker overdrive unit.

Here's some info on telling the regular and the overdrive units apart, and a picture showing the easiest way to identify them at a glance. Bottom one is the less desirable overdrive unit.

Toploader Imposters



Good Luck!
 
#12 ·
Please read the thread for more info. As outlined earlier in this old thread, the case casting number could be any version. Please post the tag info on the right (passenger) side towards the front of the case. Else, the input shaft has features that may indicate usage, and the tailshaft housing associated with general chassis type (large car, Mustang, etc.)
 
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