Howdy MC65 and All:
First, welcome to The Forum! Yes, it is that good.
You've ask a bunch of question that can be answered in part. The final answer will have to come from you. It would be helpful if you would add location to your sign-in. That would indicate elevation. Also what transmission will you be using. I'm assuming that the engine will be in a '65 Mustang. What is the octane rating of the gas you are now using?
Q- "So I'm looking at trying to pull some more power out of my 200 without seriously hampering my MPG or having to go to higher octane gas. I've heard these engines don't breath well at all and have been looking at the various head options."
A- A more powerful engine is usually a more efficient engine. The problem is it is also more fun to modulate the loud pedal= pooer mileage. It is possible to improve a '65 200 so that it will have more power and get good mileage on the same grade of gas you are now using. Breathing can be significantly improve on a stock type head (See below)
Q- "What is the benefit of the new aluminum heads from Classic Inlines?"
A- The new Aluminum head has many benefits over a cast iron head. to name a few, it is; lighter, flows significantly better, especially at higher rpms, has better heat transfer, bolts directly to stock type blocks. The down-side are; it's relative expensive, it takes specific parts in combination to get it's potential out (true of all engine), and we're still learning about it.
Although I don't believe that an aluminum head and 2V intake will yeild a 100 HP increase over a good running stock engine, it will show a significant improvement. But, If you were investing in the performance potential of a custom head, why wouldn't you optimize all the other parts too; like cam,ignition, exhaust, compression, etc... Then an increase on 100HP is within reason.
Q- "over the one from Clifford Performance?"
A- I don't know what the Clifford head package is going for right now, but in the past, they have been pricy and very well done. They are a big improvement over a stock head, but will fall short of the potential of the new alloy head. For about the same money, if I were going all out, I'd go with the C.I. head.
Q- "Is it possible to get my stock head ported and have larger valves added for signifcantly cheaper than the one from clifford?"
A- The simple answer is "YES"! The longer answer is there are several ways you could go. 1st is to rebuild your own stock head adding 1.75" intakes, with a three angle valve job on the seat and a back-cut on the valve. Go through the head as you would in a typical valve job. The 2nd option is to find a late model head (after '77). It will have the larger intake valves, a larger volume intake tract, a 1.75" carb hole and hardened valve seats. Using this later head as the foundation of a valve job significantly lowers the price of machining and parts upgrading. Add the steps listed above and milling to your goal CR. When it's finished swap the old for the new. You are now ready for improved carburetion, ignition and exhaust.
Q- "Want to get some more power but money is always a little tight. I don't want to pay substantially more for a CI aluminum head with marginal gains in power"
A- The definitions of "Tight Money", "Substantially more", and "Marginal Gains" are arbitrary. Only you can decide.
Finally, there is a wealth of information on this Forum. It is here for the taking. Many have been down this road, read and learn. Start finding your answers by answering these questions: What do you want when you're done? Are you interested in stock appearing, restomod, or ? What is a realistic budget.
One of the beauties of your car/engine/project is it is a bit of a jig-saw puzzle in that you can do it a bit at a time. But it is always good to have a goal and a plan in mind so that you don't end up back-tracking and redoing the same item.
I'm sorry to go on so, but there are really no short, or easy answers to your query.
Adios, David