[JoeC]

I emailed the seller and asked if he knew the bore size. He said he didn't and doesn't want to disassemble it to check. From my research so far Yenko sold both the ZL1 block and the CanAm block. Chevy engineering R&D (AKA Chevy Racing) was doing "research" on alu motors which was their way to finance an exotic racing motor for CanAm and other racing. Even to this day the motor is not well known but it is The King of all Big block Chevy's. Chevy was still making the CanAm block in the early seventies then had an arrangement which allowed Yenko to have some made into the 1980s. Yenko also sold ZL1s. (I'm not sure on all the details) The ZL1 used the 4.250 bore like the cast iron 427. The Alu. CanAm with cast iron sleeves block used a 4.440 bore siamese cyls design. In 1968 it used a destroked crank to get 430 cu in. and about 700hp on gas. Then in 1969 they used a 454 crank to get a 495 cu in motor about 750hp. Chevy also built a Can Am block without the cast iron sleeves and these were 509 cu in then opened up to 524 cu in. Chevy engineering actually did use the Can Am motor for research using the same siamese cyls design on the 400 cu in small block and the Alu motor with no cast iron sleeves design was used in the Vega motor. They used a cast iron coated piston to control wear. The CanAm BB Chevy motor dominated CamAm racing late 60's to early 70's beating Ferrari, Porsche, and Ford, who all had more expensive exotic engines, until Porsche went wild and built their duel turbo 1100hp 12cyl. Bill Grumpy Jenkins ran a CamAm motor in his 68 Camaro match racer and used that same 68 Camaro CanAm set-up to win the first ever Pro Stock race in 1970. Grumpy told me this himself at the Carlisle show last June. He said the ZL1 was "junk" (his word) because after a few runs they would lose a lot of HP. The ZL1 motor ran good in road racing where it only would see about 6500rpm. Drag racing pushed the motor to 8000rpm and it didn't like it. Don Yenko ran a ZL1 in his 1969 Camaro at some road races in 1969 and I believe again in 1970 Sebring 24hr. The Corvettes ran the ZL1 at Daytona and Sebring 24hr also. Grumpy ran an Alu motor in his 69 Camaro Super Stocker which at one time failed tech because Grump could not prove that at least 50 ZL1 Camaros were built. I asked if this was the ZL1 or the CanAm motor in the Super Stocker (the CanAm was legal for Pro Stock but not for SS) Grumpy laughed and said "the inspectors could not tell the difference".