will they hold

[Daytona Brad]

will the crank and the rods hold 300-400hp on a 89 2.5 turbo 1 block. and how much can they hold

[Una]

Heh, yes, easily. There are guys with the Neon DOHC heads installed on the 2.5 engine making like 450hp.. I do believe they upgraded the rods after 400hp though. I've never heard of anyone overpowering the CAST 2.5 crankshaft.. Usually the block itself goes first.. Check out the hybrid area of these forums to see guys making BIG power..