Does FT have a bigger hole in lower sprocket for bigger crank diameter?

I have a couple very good stock rollers too, but FE.  Probably 0.220.

When I did a shade tree 410 some years ago, I rolled the pockets back with a hand disk grinder and a air dremal grinder.  Ised a digital scale to keep the weight close my. I used a smaller cam, but I found both pockets too small on the Pistons I had. Don't remember the brand, Badgers I think.

If the block and/or heads have been decked and faced, it is when getting the intake faced.

Whether you do that or not, I have heat luck with two or three rows carfully applying silicine piled up to fill the gap,then gently set the intake down.

Don't gob too much on corners that can block oil drain back.

Then smooth of with fingers.

Usually use gray or black stuff.

Sweet, the 352 is such a great smooth runner. California had will almost always her 10 percent less.

Give is an update after 1000 miles.

I had something similar in my old 390, I thought it was a bad lifter. Turned out the rocker end of a pushrod had gotten funky.  I sanded it smooth and turned it over and reinstalled it. No more tick.

In the end the cam bearing clearance was gett larger, allowing rear lifters to run to lose so the were hammering rockers a little. I limped it along for a few more years with Valvoline 50w racing oil.

One comment about marine cams: they were/are intended for long hours at mid to high rpm use, ppunding the RPM from mid to high to mid to high as the boat pounds the waves, so they are sometimes easier on valve trian/valve springs then some of the bumpier cams sold today, less likely to float, and with HD springs. 

I'm not saying its better or worse, but a comment. 

Years ago i hot-rodded a Honda XR650, and I went with the HRC Honda team desert Baja 500 cam because then did not increase lift much, but increase duration with a long smooth valve action - I was putting a lot of hwy miles on the engine and did not want the valves hitting the seat so hard.

I would call Ken at Oregon cams, get a custom cam for your use and personal interest.

be careful about using "old" springs on a bigger cam like  that. Either coil bind or breaking a spring is possible.

If your springs are under 350# open, just run the new springs for break in, but use plenty of cam lube, lather the lifters, and go the chevy dealer and get a bottle of GM EOS engine run in lube (is a zinc oil to be added to the oil  for the first 20 min run it time.)

Switch to a dual plane intake is you want to get rid of the mashed potatoes below 2500 rpm.

But if you run a 416 as is, you will still be happy. 

Degree your cam, make sure you are at about 104* on the intake center line.