I'll wander happily into the crossfire again.
Look at what people race here in Australia, of the Falcon sixes. The 200 is barely used in either form (original small block or the taller-deck destroked 250). The 221 gets (or, had) a good run with 2V head appended to it. That's a motor very similar in weight to the small 200, with the extra 21 cubes.
The 250-2V got a run when newish; people tended to swap on a Holley 500. But it all faded pretty steadily as the alloy-headed crossflows took over. Again, these motors were made in 200 and 250 in³ capacity - but the overbearing preference has been the 250. Yes, it is a little lighter than a US 250, but still heavier than a '66 200 from memory. I've dragged both across the yard and speak from experience, not specific data.
One thing to note about the standard 250 is that fuel economy isn't very good. If you muliplied the mpg of a standard build 302 by (250/302), you'll find it's not the fuel consumption. So people who think it's powerful and economical are generally set to be disappointed.
Quite possibly, this above point could be reasonably addressed with a 2V head and EFI (non TBI). But that's a lot of legwork, and some new ground also. But if you're looking for a manageable package (and this is within budget) it may be a longer-term plan.
A final note on the formulas. Not decrying them, but they are approximations, designed to work with a majority of cases to provide a near-enough result. Look at a similar example. You take a Stradivarius violin. Measure the size, thickness, density etc of all the pieces, and build a replica. It looks perfect - how does it sound? Well, there's a good chance the sound will be
passable but not a patch on the original. The reason being that the parameters chosen did not include all of the pertinent detail - just like some of the above general formulae.
So, while not ignoring the number crunching, be willing to "go against the grain". If 60% of marriages end in divorce, why does anyone get married? Same deal.
Cheers, Adam.
