Parts Mismatch??

I bought an unfinished project which included a Gen VI bbc. This engine was converted to a flat tappet hydraulic cam with adjustable rockers. After about 100 miles from initial startup, it started popping thru the carb and stalled. I pulled the valve cover and found it had broken the exhaust pushrod on #1 cylinder. I figured the adjuster nut had come loose, so I replaced them all along with the push rod and guide plate.(the plate showed wear towards the rear of the engine). Less than 50 miles later, the same thing has happened on the exhaust side of cylinder #7.(same wear showing on guide plate). What do you think is going on? Can flat tappet cams be used in these engines or must they stay with roller cams?? Any theories would be appreciated.

yes i would say you can put a flat lifter cam in one but why would you want to do that ? there is nothing wrong with making the valve train adjustable but you need to use the right parts the push rods many show some small wear you need to look at the push rods check for them for out of round( bent) and you need the right size pushrod length. roller cam push rods can not be used with you flat lifter cam you need to check the valve train for thing hiting that could be piston to valve .valve retainer to guide rocker to stud there can be other stuff but thats a start

Thanks for your input. I checked the items you suggested and it seems the rockers don,t have enough travel and are hitting the studs. I have seen rockers that have a longer slot for high lift cams. Do you think these would solve the problem?
Also, if I decide to change to a milder cam and go to a roller, could I use the less expensive GM roller lifters since this is a Gen VI motor?
Thanks again for your help.

you can get long slot rockers or open up the slots with a die grinder with a stone .yes the stock roller lifters will work fine to mild 500 lift. take out cams are not that much thru comp products if they have any in stock