I'm assuming lift under .400 will work fine, yes?

 

Why would you put a 200cc head on a 305?
Most run 195's on 383's
What is your compression going to be with a 50cc chamber?

 

You're kidding right?
Those high end heads, and you won't to know if lift under .400" is ok?? I assume that's a typo?

And yes, 200cc heads on a 305 will run VERY poorly under 3500 RPM or so.

Wait, wait, aren't you the same guy from that other goofy thread I posted on a few days ago? From a quick glance it looks like some real experts have come in there to set you straight. I hope you don't require that assistance in this assinine thread as well?

FWIW - 50cc heads will give about a 10.5:1 or so, given flat tops on a 305.

 

Based on your other thread, I think you need to take a step back and do some research and learn some basics before tying to move forward with your 305. The setup you propose is a mis-match from hell.

 

an LO3 is said by Atilla to be 8.8:1 stock with 55cc. So the 180cc version of these, or the EngineQuest offerings, which I'm sure exist as 180cc with 50cc, would then be around like 9.2:1 unless you use composite headgaskets, then you'd be around 9.0:1. Edelbrock claims that if you use their 2.02"-valved heads on a 305, you can only run 0.450" valve lift. There are lift rule cams for dirt oval racing, and COMP offers a bunch of .450" hydraulic roller lobes. Still, even with 180cc I'd think a 3000-stall and 4.10:1 would be in order.

 

I can see the heads working on a limited class track engine but for the street why would you run a big valve hi flowing head and then limit it's output by restricting the lift