Actually, he had trouble with the offset cap rods in a SBC as the rod caps on one bank hit the cam lobes! 409's had plenty of room at the cam, and apparently those Porsche boxer engines had no problem. When ya modify stuff "stock stuff" can get in the way. ***DANGER!!***Nostalgia Alert!*** He also built my DOHC cam gear drive idea on SBC. It was a plate with gears running off the back of the crank sandwiched between the engine and the trans. It was only 1.5" thick, gears from CAT?***EEEEK! There's More!*** IIRC the heads were mid 80's Nissan V6?, 2 cut up, welded together to make 4 chambers. Front of the engine remained the same. Cam became an oil pump jack shaft. Oddly nobody loved it? Darn. ***Oh My! And Even More!***In north Atlanta in the early 90's "Nissan Finance lease holders" were blowing up motors in the 80's Z cars like popcorn! A big Import repair shop would send me 5-6 cars a week!, they paid me a flat rate for each teardown. (Some I could pronounce dead on the first head! KA-Ching!$$) A case of lazy/uncaring "Leasors" not replacing cam belts; bent valves, valve heads into pistons and ventilated cylinder walls, CARNAGE!, causing these 4-5 y/o cars to be worth $0. Repairing or replacing the engine(heads were usually repairable) was more than the KBB value. (The bodies fed a race series! Ahh, good times!) I got paid consistently and kept the lights on at our little Chevy resto shop for a few months longer.