291????? Maybe you mean "261"? Since it's got 4 main bearings instead of 7, it's obviously not a 292. If the bore size of the cylinders is 3 3/4", it is going to be a 261. Canadian casting numbers are very different than USA numbers, and the 261 engine was used in Canadian "Pontiac" cars for several years. That one had hydraulic valve lifters. The USA truck 261's used solid lifters. If there's a large diameter oil passage connecting all the valve lifter bores from front to back, you've got a hydraulic lifter Pontiac car engine.
Jerry

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