You live far away and everything that you do should work right the first time. So I'm not in favor of anything that is too complicated.
Also, you are talking to a bunch of racers here and they will suggest race parts. For example, B1-BS heads are race heads and are not a true bolt-on. I don't believe they can use your stock rocker arms and pushrods. They also require a bit of machine work and setup, more than the Edelbrock heads. Forget them.

IF you are planning a stroker down the road don't buy a set of different 400 pistons at this point. Again, it's not worth it. Do whatever it takes to get to the next performance level and enjoy driving the car. I have projects that I got trapped in the "as long as I'm doing this..." syndrome. They are still not done after years and years. I do not recommend this approach for others, having learned the hard way myself. I have a garage full of parts that are now obsolete because of new improved designs. If I'd put them together when I bought them it would be okay. But now using them doesn't make sense. And nobody else wants them either.

I trust you can do all the structural work to the car yourself, or get it done. It is more fun to drive a car if it can go around a corner at speed. Same with stopping.

Your suggested engine modifications should increase power by 35% or so. That's noticeable.

Another thing, I doubt that you'll notice a difference between the large or the slightly larger Thermoquad. Both are large enough for your projected power level. If your carburetor works now, I'd suggest putting money into tuning it, rather than replacing it with another 30+ year old carburetor.

I have a wall full of carburetors and they are becoming less valuable as time goes by. A self-tuning fuel injection system is easier and better for 90% of the people who are still using carburetors.

Best Regards,
R.

Here's an example of a piston that'd replace a stock piston and increase compression while using all the other stock parts. The Keith Black KB240 has a compression height of 1.908 and will increase your compression ratio by nearly 2 points. It has huge valve notches which will swallow any extra lift you are planning. They are close to stock weight so no rebalancing required. Campbell Enterprises has them with new rings for around $520.00, but if adding pistons one really needs to bore to the next oversize which adds another $200 or more, plus cleaning the block, $100, plus pressing pins in and out which adds at least another $100.

So with the small chamber Edelbrocks you are looking at around 10.5:1 compression, will still run on pump Premium, but it will cost you at least another $900 plus shipping. This would be a really nice engine, and if you went that way I'd suggest the next larger Voodoo camshaft. You may not need to do anything else to the motor. It'd make an easy 440 or 450 hp.

Choices, choices.......