Glad to hear you've found your weakpoint on bench BG. I am the opposite, with extremely strong pecs and shoulders that seem to lag in comparison. What you need to remember: if your shoulders and tries can lift 400 but your pecs can only handle 325, you're only going to be able to bench 325. So strengthen those pec muscles and make them your strong point... good luck and good idea about doing flies before bench, you will likely appreciate the results.
HUGE PRESSER