i heard on some Buick sites, that if you do some Head work, big cam, good intake and carb and a good set of Headers you can get 500 horse? is that true? it said it already gets 400 horse stock....
if you have $$$$$ they can make you anything. lol most builders don't like to go more than that on a stock block and some do. it is a personal preference of the builder.
It is easy to get 500hp out of a 455 Buick, but the oiling system sucks. I just got done drilling out all of the oil galleys in my 455 block and totally reworked the front aluminum housing and installed a distributor gear oiler so I can run a high volume pump. The stock blocks are ok for 500+ applications but will blow the main webs out the bottom at around 600 HP and/or 6000 RPM. TA Performance make a main girdle that costs around 500 bucks and it costs about another 500 bucks for the machining required for installation. With the girdle the blocks are good for way more HP'
Anyway the good sites are TA Performance, Poston Buick, Performance Automotive Engines, AM&P, and Triple Shield Performance. A killer cam for a 455 Buick is the TA413, check out the dyno sheet on this cam on the Triple Shield Performance web site.
Hope this info is helpful.
buickk was my first choice.