You don't really need to use high temp or engine paint, I use glossy Rustoleom on my rebuilds. Last 350 I did was painted black, really sharp. Block/head temps don't get high enough to burn or discolor paint. Just remember to prep and clean the block well before painting to remove oil.
'45 Ford GPW; '73 CJ5, 350/NP435/D20 w/Terlow gears, locked D30/D44; '13 CJ8, 304/T150/D20/D30/AMC20 w/locker and limited slip (T18 and Teralow gears in future); '88 Dodge RC, 360/NP435/NP205/D60s