Getting ready to purchase a set of pushrods for my engine 1957 292 G heads  290# open spring pressures
I see there are many different brands and prices available? 
what are the better ones available?

The best are the custom ones from Smith Bros.. 5/16 Chrome  Moly .060 wall with correct length and cup size.. They know what they are doing.
The off the shelf brands like Speed Pro and Melling are ok, probably made by same mfg. and should handle 300 lb  of spring pressure. Make SURE the cup end and the rocker adjust ball are compatible.. I ignored that and broke the push rod cup one time

Mummert/ford-y-block.com sells them as well, but I don't know who makes them.

Thanks
it says Mummerts are chrome moly also.