Oh, it's already in the boat. Probably no room to pull the cam out, eh?

Horsepower w/HP500 cam - oh, probably 10 to 15. Not enough to warrant the change on horsepower alone. If the motor was still in the garage and the crate cam was new (it's used now), then I'd ebay the crate cam and find an inexpensive HP500 takeout and swap for probably a net cost of $40.

With your cam being used, it ain't gonna bring much money.
With the motor in the boat, you may not have room to pull the stick out.

You're right.
Buy a gear.

I used to run a bronze gear with my solid roller but at the end of the season I tried a composite material gear at the advise of my engine builder/mentor. I don't know where he got it though.
I only had a chance to run it for a few hours so I can't say how strong it's wear qualities are.

Hello,Guys,
I took the flu shot, I got the flu-bad!!! First time I've been out of bed in almost a week. You can save yourself all distributor gear hastles by getting a Comp Cams distributor gear. They are some type of plastic or composit and are campatible with any cam. THEY WON'T WEAR OUT! They won't hurt the cam either. They are less than 100.00 and come to fit GM and MSD distributor shafts.