Was looking at xtreme marine comp cams. I have a gen 1 350. Would I have to change springs or anything with that type of cam? Last year I took the heads in an had a few seats fixed an new push rods an 1.5 roller tip rockers. An new springs.

Depends on what springs they put in it last year and which extreme marine cam your talking about.

Xm256h is 256/262 447/462 or the other cam was xm262h 262/268 462/477. I beleave the stock merc cam is 200/212 400/410 so would I have valve float with stock valve springs then?

comp cams recommends a spring to go with each of those camshafts. The only way to know for sure if the stock ones would work is to compare the specs, but those cams aren't that radical so they probably would (especially below 5000rpm)

I put the bigger of those 2 cams on a stock 260 motor along with the 350 mag intake and 1.52:1 comp magnums roller tips and it really didn't make much of a difference, maybe a couple miles an hour. I just don't think the stock heads have much more in them.

Was planning on doing vortech heads an a intake during this winter.

So change the cam and valve springs now and then change the heads this winter?

I would just drive it as is for the rest of the summer and then do it all this winter. I would also seriously consider a hydraulic roller cam. They are worth the extra money. You will see a big power difference with vortec heads/good cam over the stock motor, like 7-10mph on top end, depending on the boat.

If you search around the site you will find a few people who have done it including me.

You will never be spinning it fast enough to worry about valve float. You setup the springs per individual cam so they do not bind and have the correct seat pressure. They bind you will drop a valve, to much seat pressure and can wipe a cam lobe off.

I also would leave it alone and enjoy what you have. If you do decide to change it go with a hydraulic roller cam. There is no reason to ever use a flat tappet anymore.

Good luck.

Well motors out of the boat right now just figured a cam would give me something for right now. Boats a 85 wellcraft nova 23xl shes heavy an slow at about 43mph. But can take some big waves out in lake Erie.

It looks like you're comparing comp's advertised duration to the stock cams duration at .050 here.

I would echo the strong recommendation for a hydraulic roller cam. Crower has a nice series that would be worth looking into as well. I'm running their EFI/NOS/Blower series hyd roller and it works great. It has a lot of lift (.525/.545) so if using a Vortec head it would require machining.