Having built a lot of engines and a lot of dyno time I highly recommend the Total Seal gapless top ring sets. Easiest cheapest HP you'll ever get.
They now have a gas ported ring set. I've not had opportunity to use it but from everything I've heard and read it's even better. Might be worth considering.

Thanks, got me reading about gapless rings in the middle of the night. Interesting reading, whats the downside, i assume the cause some drag but if the upside is more compression which leads to more hp. Whats the lifespan line, I haven't seen anyone mentioning that. From the looks of things they make several model's have you tried any for the long term ? What about end gap and adding boost, i doubt I will add boost but I dont want to have to tear down the motor to refile the end gap.?

Only true longevity test I have is 3500 passes in my drag car. 3600# running mid-low 10sec 1/4 mile with a 468 iron headed Olds. But I've never had a customer experience any problem with them either. They will wear as long as any other ring set and actually have less drag based on actual pull testing of piston with rings in the bore.

I am gonna try the ported set. I dont think I will have this engine dynoed , so I wont have any real numbers. One of the main reasons I want to build myself v. store bought short block is the rings. I feel you are just leaving horsepower on the table without them. And I am still in the oldschool on oil viscosity. I like bigger clearances and heavy oil. I dont know enough about the science of tighter clearance thinner oil. I am sure it adds some power, but is it as sturdy?

An Olds powered drag car, you are my hero! My first car was a '68 442 with a Ram Rod 400. I loved that car, and still love Oldsmobiles.

The key to tighter clearances is precision. Have to have someone who knows how to properly align hone a block for starters. Durability wise they will last just as long, probably longer, as the big clearance stuff. Plus you can use lighter oil for less drag. Never got to test the theory. But have built a few that way and no more issues than building loose. But do what comfortable for you. Peace of mind is worth a lot.

My machine shop, is good, but they have aging machines and they are not state of the art. Very good to know on the longevity of the tight clearance thin oil in marine application. This is where most builders(store bought engines and partial engines) are at, and sometimes you just cant wait for a machine shop to get to you lol.

I just built 502’s. And had them dynoed ,Here’s my combination, New GM 502 blocks, 308 dart iron heads, mercury 500efi crank, Scat rods, srp small dome pistons, 9.5 compression, crane 741 cam, crower solid roller lifters, comp roller rocker, edelbrock Victor intake, 850 AED Carburetor. Max torque was 636 @ 4700 and max HP was 622.

Depending on what you're trying to achieve (and I'm not an expert) but I would be tempted to just get the short block delivered. Save headaches, hedge against the unknowns, sell whatever you can and go boating.

You can sell that you have to close the gap in costs, there are unknowns that you haven't seen yet that will add several hundred dollars and you might get a few weeks into it and find hidden costs or issues to address. Order the block, drop the heads and intake on and focus on getting it ready for spring. I went down a similar path, and probably just should have bought some drop inns.....

In my research, most do not recommend gapless rings. You can do a search online to get info.