to help answer your question, i ran 50 psi boost into a calculator for a turbo system.
it would need 120 lb/hr injectors x 6 running @ about 90 psi
hp would be around 1050.0
tq around 850 ft lbs
i think the block would need some serious prepping and added bracing to achieve that, even with that it would need replacing continuously.
i have run up to 12-14 lb boost on a relatively stock block, no problems yet on the 292. some others are pushing more, but i will let them answer how much. i bet a 250 could take 25 lbs with out to much for issues(be reliable). tom
