Proper transaxle mount bolt length

[wkrtsm]

About 35 years ago, I stopped in Ron Roland's shop, and I had a transaxle mount bolt missing, so he replaced it. Now that I am going over engine/transaxle cleaning, powder coating, chroming, etc., I am wondering if the 4" or 4.5" bolt is the correct one (see attached images). Based on the grime/grease patterns in the threads, the shorter bolt looks like only about 3/8" of the threads were used, while the longer bolt appears like all the threads were used.

I am replacing these with new zinc-coated variants, and want the same appropriate bolt length.

Below is the 4" inch bolt:



Below is the 4.5" bolt:

[wkrtsm]

Found out these bolts are supposed to be 105 mm long, so 4-1/8" -- I'll settle with the existing 4" and get a new 8-line metric 4".

[WFBowen]

These are factory originals off my 68. There were 2 supports used - the early 911/912 type with the round rubber isolators and the 912 specific type which used the rubber blocks. Each type takes a different length bolt.

[WFBowen]

And... see numbers 28 and 39 below.

[wkrtsm]

Many thanks, I'll switch to the 4-1/2" now that you have shown it's the stock OEM part from your '68.