Splayed mains? um, what block, and why? Not trying to come across rough but I think your missing something here. When pushing a gasser to 650 hp or so, and 800 torque, turning a 2 bolt main AND STRONG BLOCK, will help strengthen an over stressed crankshaft from to much movement. The 6.5 is already a 4 bolt main, that is a very weak block. Taking more meat out of the block to change the angle of the main cap bolts are not going to keep the block from cracking. Show me 2 crankshafts that came apart that had good harmonic balancers on them and the block is still perfect. Find 1- I call it a fluke. Find 2 and you could have something.
In the fleets I ran, I am very willing to bet I dealt with more broken cranks and blown out bottom ends than just about anyone out there. Hundreds of trucks in a couple of fleets. Some of the trucks ticked off over 27,000 miles a month. Engines shut off only for oil changes done at 10,000 mile intervals while the driver sat in the seat. 3 mechanics on the truck like a friggin nascar pit crew. All PMs done in less than 10 minutes and back on the road. Dozens of crankshafts into pieces. Wore out and killed well over 100 6.5s. The balancers go and it kills the crank and block. The lower end assemblies are horribly out of balance from the factory compared to modern stuff.
How do some guys get high mileage on 1 balancer and no block damage? Easy- when the rings and cylinders wear out too much to run, pull the lower rotating assy and have it balance checked. It will be in amazing tolerance numbers. BTDT.
I don't want to stop anyone from experimenting and having fun. Tear into it, you never know what you'll learn and the memories you'll create. But reinventing the wagon wheel because it's 44" tall to give you more ground clearance, and skinnier for less drag is what this reminds me of. Yeah you could do it, and you making a change that sorta sounds like a good idea at first. But the problems you are introducing is going to amplify other outstanding issues that are already known, addressed, and moved on from. I turned a sbc into a 2 stroke just because it was fun. Full roller bearing crank and all. Completely impractical and when it came apart people were ducking from parts 100 flippin miles around! But I had $35,000 to waste on the project and more importantly, I did my research before hand to know that it was all a waste of money before I started.
Back to the op- Anything yet? If you gave up on it have you thought of going another route like nitrogen depleted chambers to make up for a slow flame front (Hmm, where has Will pumped a few more $ into experimenting) or maybe some injected isobutene into the chamber to offset the draws of idi diesel fuel while not causing quite as much havoc as propane? Ever figure out how hot you can get diesel under 2,000 psi to accelerate the burn rate once it dumps into the prechamber? Lots to play with out there.
