I think he's talking about an Isky 505T. It's a solid lifter flat tappet cam used in a IMCA and Wissota modified, 2-bbl class running on 1/4 and 3/8 mile tracks. It's 254*/254* @ 0.050" tappet lift, ground on 108 LDA, 0.505" / 0.505" theoretical valve lift, 0.030" / 0.030" valve lash hot. Makes power from 3,000-7,000 in a 350. Would probably make power 1000 rpm's higher in a 283, so 4,000-8,000. You'd need 11.5:1 to 12.5:1 static c.r. to run this cam.
At 8,000, the 283 would be moving the same amount of air as a 350 at 6,500, so choose your heads accordingly.
One more thing, if I were thinking about doing this, I'd get in touch with Brodix and figure out a cylinder head with 40 cc chambers so I could use flat-tops. A 0.030"-over 283 with flat-tops w/6 cc's of valve relief, an 8 cc gasket and zero deck will compute out to 11.9:`1 using a 40 cc head.