I lost an engine for the very same reason.....stupidity on my part....and it only took 10 miles with an iron gear against a new roller cam! After an expensive rebuild I installed the only other gear available for the MSD 351 distributor...the bronze gear. After less than 500 miles it was almost gone too. It was only then that I listened to my engine shop when it suggested that I trash the high volume
oil pump and install a standard. I'd been running almost 80 lbs of pressure and the standard dropped it to around 60 or so running.....It also stopped all the gear wear.. That was almost a year ago..
I was at the local speed shop the other day and discovered that MSD has recently come out with a hardened steel gear for the 351 distributor. It is also .001" larger on the shaft bore so that you needn't heat it to install it or drive or press it on....makes it much nicer to use...especially when trying to set the end play.
