Six years ago we shared a unique 1971 Corvette being built by owner Richard Hayes with an all-aluminum BMW M73 V12 and Tremec TKO five-speed manual. The V12 features Jenvey 40 mm individual throttle bodies, 3-stage dry sump, stainless steel side exhaust, and Megasquirt MS3Pro ECU. The Corvette rides on a Vansteel coilovers with an electric power steering rack and Wilwood 14-inch brakes with six-piston calipers in front. Richard celebrated his hard work with the first test drive.
Source: Richard Hayes and Corvette Forum (build thread)
“with an all-aluminum 5.3 L BMW M72 V12”
BMW developed the M72 engine, it was supposed to be a DOHC version of the M70, but they didn’t put it into production. So it can’t be that engine.
Thanks. No idea where I got M72 from. Article is updated.
Fascinating! But I’m most curious about the transmission swap, since the M73 was never offered with a manual, only the 5-speed auto. The 8-series that did offer a 6-speed manual as option, but that V12 was the predecessor, the M70. The bellhousing pattern is different. Many people who do V12 conversions + manual conversions opt for the M70 because of this. And also the fact (IIRC) the M70 has heads and intake designs that allow for greater gains compared to the M73, which despite being more powerful, it was intended to be more fuel-efficient too.
The M70 and M73 share the same block. The heads are different and the timing chain cover. The M70 heads don’t flow well at all- and with a low 8:1 compression versus 10:1 on the M73- the M70 lends itself to boosted applications. The Intakes manifolds are the same- the exhaust is much improved on the M73. The M70 also has about three times the production numbers as the M73.
The bellhousing bolt pattern is the same between the two. I made a custom bellhousing with a Chevy trans bolt pattern. The Flywheel is off a E31 AKA 850i( the rare 6 speed version)-it was also drilled and pinned to fit a Chevy clutch. A hydraulic throw out and it was good to go.
How do you handle the crank sensors that on the m73 the teeth for detect the crank sensor es are placed on the
Automatic transmission flywheel
He used the stock m70 cps and the timing cover. If you wanted to use the stock, M 73 crank sensor, you would have to cut the bell housing off the automatic transmission so that you could have room to place them