Just trying to get a little more power out of my motor.It is a 540 with dart heads single plane with a 1050.the cam is 632/620 with a 1.7 rocker. I was wonder if i put a 1.8 if i would gain any hp. I was thinking of changing the cam but thought this might work. Any thoughts?

When I have done upgrades I was advised not to do that. It changes the geometry of the valvetrain. Best bet would be to just get the correct cam for what you want to do. Do you have flat tappet or a roller cam? Roller is the way to go, I gained 5MPH with a custom cam from RMbuilder. I have tried several different off the shelf flat tappet cams and never been satisfied.
I just read your post over again, you must have a roller with that amount of lift. What cam do you have now? Do you know were it builds peak power? I set mine up to run at 5500RPM. Some guys actually use cams with too much duration and they build peak at 6000+RPM.

I have had good luck by doing this, But it has been on basically stock engines. You really need to know what you have inside as far as clearances on piston and what the cam is now with port size, valve size, etc.... I am going with RMbuilder over the winter on a cam also. Good luck, Robby

I with a friend of mine who builds alot of circle track engines. he said about a 10 hp gain also to check valve clearence 10 degrease before and after top dead.For ten Hp I think I am better off changing the cam.

You better get as much power out of that 540 for this season coming up!!

Don't forget to check for coil bind (springs).
I was going to try it a few years ago, bought a set of 1.8 then decided not to do it. IMO not worth it for a little gain.

I am running the 1.8 on my 540 bbc and did not notice any change from the 1.7 .

On a 540 have seen 15HP by putting 1.8's on the exhaust side only. 15HP on a twin engine boat is 30HP. I run 1.8's on my exhaust side.

Your Dart heads will still flow air @ .650" so it wouldn't hurt.

Talk is cheap!!!!!!! Soon we will see

You got that right!!