If you have to use stock internals, zero deck the block and mill the heads to bring the compression ratios up. Then, port the heads. Depending on how high you can get the compression ratio, you might be able to get the engine well over 185 hp. If you're allowed, you can use 1.6 rockers to make that stock cam seem a little bigger. Do some tweaking on your ignition timing, factory curves are probably far from ideal.