372or 416 and why
340, yup. $448 strictly for the valve job to be exact. And that doesnt include seats or guides, or spring seat work or guide trimming or milling. $1000 just for the labor on a set of typical X heads that are whipped and have to be checked for cracks. Flowbench work is $100/hr. I also buy my parts thru the shop because I believe in letting them earn a living and stay in business as opposed to bringing in everything and saving a few bucks so they starve. Even the shops that have all kinds of problems around here charge more than $225. Which is why I drive 1.5 hrs one way to this place.
If my math is right on your heads, and generalizing a little for pricing and substituting rough cost for anyone to duplicate your time in porting... You've got $628 + 60= $688. That includes the valves. So, a set up of springs retainers, locks, and seals from Comp lets say goes another $250ish (bought thru a shop) or $938 without your grinding time. The typical stage one port goes around $250 from most places.So $1188.00 Not unreasonable to assume at all.
I do know CT is the most expensive state in the country to live in. So I'm sure some goes into that. But still, using your numbers... You got 240cfm from those. A set of RPMs from summit today is $734.50 x 2 or $1469.00 Add that $175 valve job you mentioned and we're up to $1643.00. A difference of $455. I'd still take less weight and better chamber for that $450. I'll also make more power with them and be more pump gas friendly.