Do you have the original Corvette ECM? If so, I would recommend getting a Painless Harness like Trees said. You will not need a custom chip if running the stock engine with the donor car ECM. But you will have to research the VATS issue. Not sure if 85-86 was applicable. If it is, that will be a problem and it will need to be deactivated (by you or a chip burner).
If you do not have the original ECM, I would recommend converting the EMS (engine management system) over to the Holley C950 system. The system you will need is P/N 950-101 system which is for GM TPI engines, and is about $968 (Summit Racing P/N HLY-950-101). You may wish to consider the C950 option even if you have the donor ECM and/or harness.
The 950-101 package includes the ECU, software, base maps, harness, MAP sensor, air temperature sensor, 3-wire heated oxygen sensor, and main relay. Because it is designed for TPI systems, it also includes the adapter harness (P/N 950-138) for small cap HEI distributors, if that is what you want to run. But you should be able to use the large cap HEI distributor that is most likely on that engine, as long as it is an electronically controlled HEI.
I know it's easy tell someone else to spend a grand, but you will be money ahead in the long run. By the time you get a Painless harness and chip (if needed to delete the VATS), you'll be close to the C950 and have no emulation ability in tuning (live tuning). You can opt to tune the EPROM yourself, but you need to buy equipment and learn how to do it. This is a moderate expense, depending on if you want the ability to tune live. DIY-PROM also has a large learning curve.
The C950 is a speed-density system and can emulate and this will let you dial in the engine no matter what cam, heads, etc. you have at the time. And the C950 will give you the option to add Wideband O2 later if you want. The C950 will make for a very clean swap with few headaches.
If you have a 700R4 and use a lock-up converter, with the C950 you will have to get a stand alone lock-up kit (B&M, TCI, etc.), or go hydraulic lock-up, or no lock-up. The C950 also does not require a VSS input signal, whereas a stock ECM really needs VSS to operate properly.
Here is some information on DIY-PROM (my experience):
http://www.tpisuburban.edgesz28.com/tuning/suburban-tuning.htm
Here is a page showing my conversion to a C950 EMS for my Camaro:
http://www.edgesz28.com/edgesz28/fuel.htm
EDIT: This article is linked on my DIY-PROM page, but it is a great summary of the DIY-PROM process. Lots of terms, equipment and resource links.
http://www.tpisuburban.edgesz28.com/tuning/chips_know_it_all-200.pdf
Best of luck, Ed
www.edgesz28.com