• Consider headers, oil pans, and the mounting points on the engine
• Is your ring gear 3/8” from the engine plate – indicating a typical manual transmission starter?
• Or is it closer to a 3/4” -requiring a typical auto transmission unit?

Which starter to use is a common question and a common source of frustration for people doing a T5 or TKO conversion behind a Ford Small Block.
The challenge stems from the misinformation in the literature and from the starter manufacturers themselves.
It was and still is, very common to read that you need a starter for a manual transmission (M/T).

But this is not enough.  It really depends on the flywheel size being used.
Small block Fords (260, 289,302,351w, 351c, 5.0L) can except either the 157 tooth or the 164 tooth flywheel with the corresponding bell housing.  Early Mustangs were mostly 157 tooth, but some were 164 tooth, as well as, other Fords and trucks.

157 tooth flywheels in front of both the automatic (A/T) and the manual transmission used the same starter.  This same starter was also used with the 164 tooth automatic transmission.
It is only the 164 tooth in front of a manual trans which used a different starter (3/8″ depth).  It is this starter that people end up with which gives them grief.
The local parts store may call out this starter as the starter of choice for a “manual” transmission.  They don’t differentiate the flywheel.

So it is best to specify a starter for an “automatic” transmission as you will be using a 157 tooth flywheel in the majority of T5/TKO conversions.
If you are using original bell housing and it is for a 164 tooth flywheel then you will need the 3/8″ depth starter (see chart).

The Details

There are 2 critical dimensions, the diameter of the registration hole, and the depth of the ring gear.

 

HOVER OVER IMAGE BELOW TO ENLARGE

 

 

 

 

 

So what are our recommendations?