Many OEM engines come with them- most turbo 4 import engines, some northstar V8s, all diesels. All Nextel Cup cars F1,and LeMans cars as well- and none of those have the kind of 90 sec WOT runs you do.
The oil cools the bottom of the piston which in turn keeps the top of the piston from melting which looks like what happened.
There are basically 4 ways to do it:
1. A hole drilled in the big end of the rod with coresponding hole in the bearing. This is tough because of the timing and requires the rod oil feed hole be in the correct place. Not really an option unless you are willing to do a new crank and rods.
2. Imports come with little banjo type squirters with the fixing bolt acting as a pressure relief valve which stays closed until 25psi or so. these are usually tapped into the main galley. These are commonly available, but adapting them to an exisiting engine V8 could be a major issue. You can searc piston oilers on ebay to see some of these. Here are some Nascar ones
http://cgi.ebay.com/ebaymotors/8-Billet-Aluminum-Piston-Squirter-Oilers-Set-NASCAR-_W0QQcmdZViewItemQQhashZitem2a0c805283QQitemZ180598362755QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories3. Holes are drilled into the main saddle which connect to the back of the main bearing- small orifice/check valves are then inserted. this may be the best option. Mike Laws at BLP.com used to offer a kit for SBC that I think were like this- I don't see it anymore though, I PM'd him to see what was up
http://www.blp.com/pdf/NP2006.pdfhttp://speedtalk.com/forum/viewtopic.php?f=1&t=16264&hilit=piston+and+oiler4. External piping systems- these can take several forms- just a series of pipes inside the block or built into the pan. This just require the right parts and some patience I think
You mentioned needing an oil cooler- I'm kind of surprised you don't already have one. I think the best bet for a bville car is to use one of the many oil/water ones available and just plumb it into your existing engine cooling system they are cheap, compact and efficient