HEH-G strength.... Dennis?

Are the 25 spline output toploaders really fragile? If one has been converted to a 28 spline output will that upgrade alone make it as durable as say a factory 1-1/16 in and 28 out?


Thanks

There were warranty issues when Ford put the 25 spline output shaft behind the 289 because it was too weak--not sure if it was the shaft or the spines that were the problem. Ford then upgraded the toploader to a 28 spline output shaft, which is what the 390 had but only longer. Most people tend to stay away from the 25 spline output trannys.

Yes, the 25 spline output can be replaced with a 28 spline shaft. Otherwise, the tranny would be just as strong as the later toploaders.

One potential problem with the HEH-G is that it has a narrow case which uses a less common bolt pattern. Fine if you have an old 5 bolt 260 or 289 block before mid 1965, but not usable with the later 6 bolt blocks unless you have a scattershield that allows for it.

Here is what the front of the HEH-G would look like:



Here is what the 65' and later toploaders look like:



Note that this toploader has 2 bolt patterns, both the old pattern like the HEH-G and the new.

Here is a Lakewood scattershield that has both patterns:

The trans I was refering to is on ebay, I thought I would bid on it just to get the 17 inch extension housing and long out put shaft that someone swapped onto it. I didn't notice the early narrow mounting pattern, thanks for pointing that out!

I have to police myself, I will wind up with a garage full of these things and a bunch of money in them and still not have the correct trans for my application.

The outputshaft itself would break,not the splines.I had one when my car was a 14 sec ride,and I snapped the shaft on the street with street tires.Swapped in a 28 spline shaft and had no more problems.

Originally Posted by 68fastang

The outputshaft itself would break,not the splines.I had one when my car was a 14 sec ride,and I snapped the shaft on the street with street tires.Swapped in a 28 spline shaft and had no more problems.

I figured as much, but wasn't sure. Thanks for the verification.

Originally Posted by MCCUTCHEON4

The trans I was refering to is on ebay, I thought I would bid on it just to get the 17 inch extension housing and long out put shaft that someone swapped onto it. I didn't notice the early narrow mounting pattern, thanks for pointing that out!

I have to police myself, I will wind up with a garage full of these things and a bunch of money in them and still not have the correct trans for my application.

In that case, avoid the 64' toploaders altogether and be extra cautious with the 65's. Lots of them were produced with the wide case but still had the early 25 spline output shafts. Shoot for late 65' and newer.

Be careful of ID codes and always ask questions before a toploader purchase. The ID code on the case (HEH- or RUG-) may not (and often aren't) accurate after 40 years of abuse. Internally the 64'-73 cases are universal and the guts can be swapped from one to another, as long as the guts are from the same gear ratio.

Remain patient and the 17" stuff will come up on ebay. I have seen them go cheap at times this year.

I bought a wide case 25 spline back in the late 80's/early 90's. It was weird, as the output shaft was full sized until it got back to the splines... and at that point, it necked down to the smaller 25 spline size.

I swapped out the shaft, and it worked just fine. I believe it was one of the first ones I rebuilt.

Originally Posted by dennis111

In that case, avoid the 64' toploaders altogether and be extra cautious with the 65's. Lots of them were produced with the wide case but still had the early 25 spline output shafts. Shoot for late 65' and newer.

Be careful of ID codes and always ask questions before a toploader purchase. The ID code on the case (HEH- or RUG-) may not (and often aren't) accurate after 40 years of abuse. Internally the 64'-73 cases are universal and the guts can be swapped from one to another, as long as the guts are from the same gear ratio.

Remain patient and the 17" stuff will come up on ebay. I have seen them go cheap at times this year.

Good advice, thanks.
Actually I have been considering a Richmond lately.