I have a 410 in my wife's car. Made 535 flywheel HP on the dyno and 531 ft/lbs of torque. Has a smallish solid flat tappet in it (.576/.591 if my memory serves me right). On the dyno it peak HP was at 5800 and she shifts at 6,000 and thus far the combo has worked great. Looking at building a 2nd motor basically identical to this one with maybe a tad more compression (currently is 10.7:1, may go to 11.2:1) and different cam. If I were to just swap the cam to a roller (do you recommend a hydralic or solid) and stayed around a high 500, low 600 lift cam, how much HP increase would I be looking at?

Solid roller. Piss on hydraulic rollers. If you want to use a hydraulic roller lobe and solid lifters that works. Just lash it at .002 cold and go.

Depending on the grind, you could find 35, maybe 40 HP. Why so low on the RPM. You should be shifting it at 6800 or even 7000 if the parts are decent and your rocker arm geometry has been corrected.

The right grind and up the RPM a bit and you could find 50-60 HP maybe a bit more.

Built it to be a lower RPM small block that way it would be a low maintenance bracket motor.

With the original goal of reliability and a ~535 HP SB I think you are right there. FT cams can have reliability issues... so can rollers.

If you are running something like a stock block, 535 HP is pretty good. I would not push it. Also I would not think hydraulic roller would help much vs a well sorted FT combo. A solid roller could make more power but that may break the block sooner rather than later.

It really depends on the heads and intake more than the cam. If the heads are tapped out then a bigger cam just kills performance rather than helping. So you need to think about the entire package of compression ratio, heads, intake, exhaust and cam.

You nailed a combo--WHY screw around do it again!!!!!

What heads, intake and carb are you using now?

Figure out how much power you want to make...... and build accordingly.

Listen to Andy F
figure out how much power you want after a shift
ignore peak power if at the expense of torque below peak power where you want acceleration
chasing peak power only is a fools game- we're not racing dynos
also the poster that said that power is in the heads gets it right
get your head flows and compression figured out B 4 even thinking of cam
I hardly think your current cam is low lift especially if you have 1. 5 rockers
remember with roller rockers it really helps to move your shafts up and back
especially with long valves/ springs
so think of higher ratio rockers
longer valves and springs
lighter rods and pistons
what headers?
it's all going to be in the details going from your current build

If this is a race only deal, you can go after more hp if you are willing to run a matching converter. If you want to run it up to 6400 rpm say, then you would probably be fastest with about a 5500 stall. Like has been said already, don't chase hp at the expense of torque unless you are willing to get the right converter stall and rear gear to match. Get the airflow up as much as possible as long as port velocity doesn't get hurt. If it were mine i would be checking on a solid rollercam with endurance lobes, hopefully there is a combo that can provide lift to use all the airflow you wind up with.

If this is a race motor don't skimp on the compression. Only upping 0.5 points won't do much. If you have to run race gas or E85 then that's what you do.

RE: Camshaft - why go bigger?
Look at modern engines. New cylinder heads flow way better than old ones. They make unreal power with relatively small cams. I'd spend extra camshaft money on headwork.

R.