I found a 1990 chevy 350 out of a Capice or something and was curious about cam selection...Do you have to run a hydraulic roller cam in these blocks or can you run a hydraulic flat tappet or solid flat tappet in them? Just curious since it has a hydraulic roller in it that needs to be replaced

Yeah you can put a flat tappet cam in there without a problem. The roller pushrods are much shorter so you will have to get a set of std length pushrods and of course use a timing set for a flat tappet cam.

Is the engine a factory roller or a flat tappet cam

'87+ that came in cars were all roller cams. Trucks used flat tappet cams BUT the same blocks that the cars used. Some trucks came with the finish-machining done for the roller cam components, some did not, as they didn't use roller cams. But ALL cars came with roller cams.

Look in the lifter valley of the block - if the 3 cast-in 'stands' in the middle of the lifter valley are machined flat on top and tapped for bolts, then its ready to rock with the factory roller lifters and 'spider' bracket. If they are there but not machined/tapped, then it was an unfinished block used in a truck. Those 'stands' need to be machined off and tapped to use factory roller parts.

Mine is a roller block

Yeah you can put a flat tappet cam in there without a problem. The roller pushrods are much shorter so you will have to get a set of std length pushrods and of course use a timing set for a flat tappet cam.

If you have the complete roller set-up already, spend the money for a different roller cam and valve springs that match. Your roller lifters can be reused, saving you $$.

No need in stepping down on power, economy and driveability.

yeah i just picked up a factory roller block. Spend the coin and get a roller cam, there is no point to going backwards in technology for a flat tappet cam that may fail, when you are all set to put a roller in it already.