if the tires are 20 years old, dont try to reinflate them and drive public streets with them.
battery: nothing special. unless youre gonna run high powered audio
yes drain the oil, replace with new OIL filter. and then you should prime the engine by rotating the pump, you dont have to rotate anything else but the pump (if its anything like the 4 cylinder datsuns.)
How to Prime oil pump on a new L motor before first start up - How-To - Ratsun Forums
my datsun sat for only 5+ years in socal and even with fuel in the tank, a lot of rust accumulated in the tank.
save yourself the trouble of clogged lines, filters, etc by dropping the tank and at least inspecting it. there are a few diy ways to clean the tank but after going through it, NEXT time im just going to take it to be cleaned at a radiator shop. while youre at it, replace the associated rubber fuel lines.
coolant system, drain & flush the system.
the transmission is sealed so i dont think its degraded over the past 20 years but if you
feel like replacing it, go ahead. ensure you get yellow metal safe fluid. not just any fluid will do. oreilly, autozone, pepboys, and a few others didnt have it. Napa does. sta lube makes it.
brakes: might as well flush out the old brake fluid and replace it with new, then bleed the system. the rest of the braking system should be good.
if you dont have an account on ratsun already, go ahead and sign up. LOTS of helpful info on there and theyre a lot nicer. it will your most favorite forum in the world.
oh lastly
i hate that youre gonna take a 20+ garaged Z and throw
in an LS1. it would be such an awesome resto project. at the least you could
sell this Z for a good price, buy another, and then make that your project car.
but hey thats just my opinion, do what you want with your car
