340 vs 360

At rock bottom, and understand the limitations of that choice, a 408 or 416 can be built for about $500 more than a 340 or 360. It's not how I like to build, but sometimes that's what the customer wants.

It breaks down like this: Scat 4" crank $300. Sonic test block $175. Clearance block $75. Redone factory rods $225. Hypereutectic pistons $300. Internal balance $450 w/Mallory. Total of $1525.

vs: factory crank redone $300. Recon'd factory rods $225. Hypereutectic pistons $280. Internal balance $300. Total of $1105

Both of these would obviously need the rest of what I consider "required" machining. Neither of these are crazy builds, but the hypers on a 4" crank run the risk of pulling apart over 6K rpm because the piston speeds go way up, and the cheap Scat crank is one of the weakest ones out there so it can flex at higher power levels. So I set a 5500rpm max rule on them. However, under 5500, these will far outpower a 360 or 340. The hypers will not reach the "fly apart" rpm threshold on a 3.58 crank until you get past 7K rpm. And it basically wont be reached on a 3.31 stroke. Sell the 340 block, build a 408 off that 360. A 408 turned to 5000rpm will last as long as a 360 that has to turn to 6K to get the same ETs.