I thought the 6293's were just the SAE version of the 8445's. Maybe I'm wrong though. It certainly wouldn't be the first time.
Most 6293s don't have the bridged water passages. Some do. Kind of weird but I've seen both versions in the junkyards. Otherwise they're identical. My '84 4.1 had 8445 heads but who knows the history of the motor.
My dad went through a few 4.1 blocks before he found one without cracks in the deck or thin cylinder walls. I think one block had a cylinder thickness of .040 or less. Mine were all .180 or thicker. I'm wondering what caused the cracks in the deck because the NA 4.1L only made 120hp. I removed the first couple threads from the headbolt holes and used headstuds and so far so good even with some severe detonation. Threw a girdle on it too, just in case.
My 4.1L is a great street motor. I basically transferred the parts from the 3.8 to the 4.1. Biggest difference was in spool. The turbo was lazy with the 3.8L, partially my fault because I only had a 2,800 stall, but with the 4.1 it spools much, much better. Could also be from the slight compression bump. The 212-212 flat tappet cam idles perfectly smooth but I think it could use a bigger cam. If I ever get bored enough I might try the 218. I would never build another 3.8 for a street car. If you're looking for a 9 sec stock block you're probably better off with the 109. I just found a virgin never been assembled 4.1 stageII block for $200 so that's my project for the next 2 years. What a waste of a stage motor, going in an 84 GN lol.
