225 /6's created equal?
Just be very careful when working the ports. More than one enthusiast has hit water getting carried away.
Look into bigger valves. There are lots of options. The Engine Builder valves are very popular, and require the least machine work. Best bang for the buck.
If you have a substantial overbore, 300 Ford Valves will work, but there is some work to do with that mod. The stems are smaller, so Guides need to be done. The seats need to be cut, or larger seats installed. That's tricky because once again, there's water to hit. This requires bowl work to keep from masking the valves, and if your industrious, relieving the bore for valve clearance and to keep the cylinder wall from masking the valve also.
With a .045" Overbore, I smacked some intakes into the top of the cylinder wall. Make sure the head is centered over the bores! My head is slightly offset to the rear on the stock dowl location. Make or buy offset dowls to correct this before putting the engine back together!
I don't think this would have been an issue with a .060-.100" overbore. There are a few larger overbore packages out there, but once you clear .060" Over, it's imperative to check for core shift!
Oh, and by the way, the lotus hyperpak was a factory one off racer. They did all kinds of stuff to that engine and head. The pistons were different as well. Just bolting on the parts that came with the option package does not a 200hp engine make...
The HP rating for the stock 225 mechanical cam engine across all years is the same. The changes were from measurement methodology. Gross and Net. Some of the smog equipment pulled the engine down, but the Gross was still the same.
CJ