Engine Build Ideas...PLEASE HELP.

Wow, this sure spiraled a bit..
340, I still think you're a little too general, but everybody's got opinions. Here's a few more of mine.

The 340 with the FM kit is a good solid rebuild kit. There are some major differences in machining that 340 may not be aware of, at least not by his postings (again, maybe a little too green at it or just holding back...). That kit uses heavy forged pistons, and in a cast crank 340 like the '72 should be, you will pay more to internally balance it. Mallory slugs are close to $100 for the amount you'll need. The heads when looked at by any shop that does real performance work will need at least $1000 worth of parts and work if two things are true: They are stock used heads; the shop uses modern equipment. Reason being the equipment that uses a straight pilot to center the tooling for the valve job needs a perfect guide. He has money in there, but not enough IMO for seats and guides. You don't ned the small valve seals with a single spring setup. Then you got the parts, which for me are valves, springs, retainers, locks, guides, and seats. Using cheaper stuff will keep some cost down. But a $175 valve job as not going to be very good. No exceptions to that. Balancing costs a lot more than his numbers show. As does most operations even on older equipment near me. but I'm in CT and breathing is expensive here. The main bores can be checked, may not need align honing. Dont replace the main bolts. I wouldnt run an MP cam unless someone force me to. The tools to properly measure and assemble the engine will run another few hundred for cheap stuff, and dont forget the lifter bore burnishing tool and the dist drive bushing burnisher. Have a shop install the cam bearings. the tools to do it are fairly expensive and not worth it for one or two rebuilds if you're on a budget. DO NOT HOME PORT YOUR HEADS!!! Get that one?In any event, a stock rebuild plus a few tricks and a cam is what you want. In most areas of the country will run somewhere between $3000 and $4500 depending on the shop and the parts chosen. A 4" arm engine will run about 25% more. In terms of HP/$... I use 300-350 - $11/hp 350-450 -$12/hp 450-550 - $15/hp 550+ budget $17/hp or more. The smaller the displacement, the more cash it takes to get the higher levels. I should also say there are ways to cut corners if you are savvy. The 440 in my bussies Cuda cost $1700 without the 6pack, and makes 480hp, and 530tq at 3200rpm on pump fuel witha hydraulic cam. It's not "all new" or anywhere near perfect, but you might be surprised what a good engine guy can do with mild parts. So anyways, flame away... It's a fun read :)