The stovebolt screws hold the timing cover on. And don't forget the two bolts at the bottom I've mentioned. They go in from inside the oil pan, thru the front main cap and front plate, into the threads of the timing cover. When installing water pump, test fit bolts thru pump and make sure they stick out of pump an equal amount, about 1/2" inch or so. Use thread tape on water pump bolts to prevent leaks. Make sure to not confuse those bolts with the ones that hold thermostat housing together on cylinder head. You sure you lined up timing marks on camshaft correctly? And use lots of lube on cam lobes, and squirt some 30wt oil on timing gears before installing cover.
The main thing is to not force bolts in holes. If they don't thread in easily, or they bottom out before they're tight, you're putting wrong bolt in wrong hole.
chip
