I still wouldn't go Coyote in a fox, even if the financial calculus favored them. So, I admit my bias. That said, is there anything wrong with the M-6010-BOSS 302 blocks? They're only $3k. I guess the competition would be against the $3.7k Dart SHP, or better yet, the $3,400 World Products Man o' War.
The other route would be to find a used aftermarket block on the marketplace. Here are the blocks I remember that can handle significant power. Of them, I believe the Dart Iron Eagle is the best of the best, but if you're open to anything, I'd imagine you can find a pretty good deal on one. Gonna try to go in order of superiority, based on my gut. Open to feedback...
Do we already have a thread that does a run down on all the aftermarket blocks with specs, how to identify, and Pros/Cons? Might be useful, at some point.
2k+ HP category:
- Dart Iron Eagle (4-bolt mains on all 5)
- World Products Man o' War (my understanding is neck-and-neck with Dart IE)
1k+ HP category:
- Dart Sportsman (4-bolt mains on middle 3. No problems making 12-1500 hp)
- SHP (Dart rated at 600hp. WTF? Still put here, because plenty of data out there with people making a LOT more. I thought near same as Sportsman)
- New Ford M-6010-BOSS Block (Short piston skirts may have trouble at 3.4"+ stroke, but apparently better cooling than R302. 1/2" 4-bolt middle-3 mains)
- SVO R302 (Siamese blocks, like the Darts & WP blocks. 7/16" 4-bolt middle-3 mains)
- A4 (non-siamese - limited bore size... Do the research beyond 4.060)
Sub 1k category:
- Original Boss (much thicker main webbing & 4-bolt mains. Rare, expensive, & unless restoring a Boss 302, fuhgettaboutit!)
- 60's 302 (2-bolt, thicker main webbing, 28 oz... right?)
- Mexican 302s (thicker main webbing, maybe not as much as the 60s)
- Stock/FRPP Sportsman blocks (50oz, generally accepted longevity at 500rwhp and 6,500 RPM or less)