2.7 into a '71 Targa

[trak ratt]

We have a ’71 911 Targa that is mostly original right down to the steel wheels. The engine has the usual upgrades for reliability, but is essentially a stock 911 T. The car is in excellent condition & has only recently developed a bad stumble off idle that I think is caused by a worn out Marelli distributor. I have a ’77 911S motor & would like to put into the ’71. I've replaced the bushes, shocks, tie rods and most other drive train items & at 120K the car will need a new clutch soon. I’ve also installed 26mm rear torsion bars, Bilstien Sports & a stock front sway bar (we like to AutoX). I want to keep the stock 911 transmission w/pusher clutch. Can you tell me if this will be a simple swap, or are there 10K little things that will drive me crazy? Like connecting the CIS, new fuel pump & return line, etc.