Originally Posted by Full Force (Post 4403898)

Ok so who has FACT on a cam long term with 241/246 and 681/663 lifts? Actual fact? And how long has it been ran?

Originally Posted by vintage chromoly (Post 4403883)

Anyone here have a marine kinetics cam that isn't a piece of crap? That has been in service for some time and performed to expectations?

Originally Posted by Boatally Insane (Post 4403914)

YES.. I've done two builds in the past with Marine Kinetics that both ran better than expected..
Working on my third right now... :)

Originally Posted by HaxbySpeed (Post 4403388)

Just thought I'd share some info on a line of hydraulic roller cams that work very well for marine engines. In this day and age, there are no big secrets to building BBC marine engines. No secret oil pans, magic cylinder heads, or special cams that are going to set the world on fire. You can find out everything you need by reading, and asking people who know what they're talking about. If someone won't give you an answer, it probably means they don't know. Anyway, back to cams. Going back a few years, I was having lots of valve train related issues from using custom cams. Needing to use fancy $800 lifters for a fairly basic engine, breaking rockers, all the Morel lifter failures, etc. I had a few take out zz502 cams on the shelf, so I swapped one in on a low rpm jet boat deal in place of the custom cam that was causing lifter issues. I figured it had to have a pretty stable lobe because it could run so much less spring pressure, and I was willing to give up some power from the greatly reduced lift. Surprise, it made more torque, and seven more hp. The next couple builds I tried an off the shelf Erson, it made very respectable power, but closed the valves a little harder then I was comfortable with, so the search continued. I had a customer who had purchased some custom cams for himself, and was on his second set of lifters, had multiple broken snap rings on his rockers, one trunion broken in half, and had damaged a valve stem from the lifter bleeding down at higher rpm, this was after about 25 or 30 hours. I had had excellent results with Lunati solid rollers in the past, so I picked up their catalog to check out their hyd rollers. I chose a cam with almost identical duration as the custom cam, but opened the exhaust valve just a little later, and a fair bit less lift. That probably will give up a bit of power on a computer simulator, but in reality, especially in a blown application it can help parts stay alive. We dyno'd the engine with the custom cam, and experimented a bit to see what was going on with the lifters. We pulled the cam on the dyno, and swapped in the Lunati. It made 90hp more, egts were better, it idled cleaner, lifters were quiet, etc. Same day, same dyno, same lifters. It confirmed a lot of my suspicions. On the second motor we tried some Johnson lifters in place of the Morels. They worked well, but gave up a few hundred rpm earlier then the Morels did. I'm currently running one set of morels and one set of Johnsons in the same boat to do some long term testing, and use both regularly as I've never had another Morel lifter failure since I switched to using off the shelf cams. Every Lunati cam that I have used, and other builders too, has made more power then the custom cam it was replacing, and improved performance in the boat. So.., long winded way of recommending Lunati EFI Compatible Cams. They're available in genVI, and retro, and work well for NA or low boost blown deals, carb and efi. No reversion issues. I've used almost every cam in that series and they all work great. If you want something bigger, or something custom, the Lunati Voodoo marine lobes are killer. I could right a novel about the amount of time I've spent screwing around on the dyno with custom cam issues, having to switch to solid lifters, changing springs, etc. Suffice it to say, talk to several reputable builders when you're doing your homework for your next build. When I get time I'll try and post some builds with dyno sheets and specs in case it will help any one in the future.

Originally Posted by HaxbySpeed (Post 4403892)

In my view, "aggressive" is different then unstable.

Originally Posted by HaxbySpeed (Post 4403919)

I feel like this thread is getting a little off topic. For marine 454's to 555's, we know the Crane 731, 741, 651 are all proven performers in a pretty wide range of combos. I have had really good luck with Lunati 20110669 234 / 244 .629 / .612 The 20110670 works awesome 238 / 248 .640 / .629 As well as the 0671 242 / 252 .640 / .629 All of those run with average spring pressures, and the smaller two I've used with stock gm lifters no issues. Any other known reliable Isky, or Howards grinds, etc. post em up. The comp XM lobes work well but don't make as much power as the lunati.

Originally Posted by sutphen 30 (Post 4403911)

what about more duration and lift?would that count.