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http://jimshea.corvettefaq.com/Looking at the AIM under UPC N40, it appears the older banjo style pump was only used on the L6 in 69. Looks like SBC V8s used pump 7805656 which was the newer style with the tank crimped to the body or what you call a big filler neck. Apparently the 396 used a different pump as it shows a different p/n in the AIM. You will also need a flex coupling/rag joint and possibly a different Pitman arm, proper pulleys for the pump, hoses, also there are some retainers to secure the hoses which should be shown in the AIM. I have no idea on the 2.5 or 3.5 turn gearbox, someone with more knowledge may chime in. If you've a numbers car there are date codes on the pumps, gearbox body and aluminum top cover.