1987 AGP trans from a 944S?

I built my 1984 944 with an early LT1 kit from RH and it currently has the stock trans installed with no modifications.I have driven the car for over a year with very few problems. The car does rev very high in fifth gear at around sixty five mph.I have an AGP trans from an 87 944S I can install but would like to ask anyone who has done this if it will lower the rpms in fifth gear. I know that FDR and fifth gear are different but I just cant get a direct answer to this question.I understand the AGP is stronger in some areas . but I would like to get the rpms down to more roadable in OD.Anyone been there,done this?

The AGP will rev even higher in 5th gear then your stock trans. The fdr is the same, but the 5th is higher.

This link shows all the 944 transmission gearing

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You can put the the taller 5th gear from your '84 transaxle into the '87 944S transaxle and it will spin at the same rpm as you had before in 5th. Otherwise, it'll spin even higher than what you have now.

To get lower rpms while cruising, you're going to need a turbo transaxle.