Got an A14 sitting here, was told it was a good runner, replaced it with a worked A15. Has everything but inlet manifold and carby, can throw a 4 speed gearbox in with it also.
It's a cool build but your living in a dream world comparing an engine with more off the shelf aftermarket parts than pretty much any other engine on earth with 6 second performance to a dinosaur L series anchor.
I used a bigport engine, made some custom mounts using shortened datsun ones on the X-member and made some simple ones coming off the engine, cut off the datsun gearbox mounts then use the toyota gearbox x-member. get a maddat hydro clutch kit generic KE70/AE86 alloy radiator. Wiring is pretty simple get a tailshaft knocked up. You can also run a AE86 center pretty easy.
Should be able to get the whole thing done for around 2k using good 2nd hand parts if you can do most of the fab work yourself.
Pretty cheap for a bullet proof twin cam injected proven engine, tough gearbox and a metric dickload of cheap, quality off the shelf parts.
keep your eye on the parts for sale section on ae86drivingclub.com , plenty of bargains and a good tech section on there.