i will agree that the run time is not as good with the big blocks, but i still recon they have more balls. a couple of the guys at the track had a drag race down the straight, both cars were the same except one had a .21 rb s7 ($370au) and one had a .28 samurai 528 ($150au) and the .28 pulled away from the .21
and as for .21s reving harder than .28 thats not true, the hyper 8 port engine revs to 38000rpm, where as the team infinity samuari 528 revs to 43000rpm. well thats what the web sites say anyway
http://www.team-infinityrc.com/produ...p_id=1&lang=EN
http://www.ofna.com/eng-hyper21-8port.html
have a look 4 your self