x2 on rebuild the carb. few bucks and you *should* be good as new. here's good start for some info:
replacements can be spendy and tracking down a good used carb for a rebuild can be a chore. starting with what you have and seeing if you can make that work is probably the most economical way to go in this instance.
Looking for some thoughts on what would it take and cost to get this running
that's a hard one and the the answer is *wildly* dependent on a number of factors. what the current condition is, how long it's been sitting, your level of mechanical skills, what level of "running" you find acceptable, what resources you have available to you and even the network of friends you have (that will help out with parts, wrenching and drinking all your beer).
you could have it running for the cost of a carb rebuild kit, a battery, some basic tune up parts. so let's call that $500. you could likely have it on the road running and reliable with fresh brakes, some fresh rubber, all the tune up stuff plus some other odds and ends for, let's say high end, $1500 bucks if none of the major components is a major problem: bad trans, bent suspension. tired motor, etx.
vs how much would I need to spend to just expedite the engine swap
so, straight away /6 to V8 is more than just plopping a motor in. that's the easy part. there are fixed costs: you will need a V8 transmission, or if it's manual, a V8 bellhousing (and clutch and pressure plate) as well as all the V8 manual trans stuff that's specific to 64~66 cars. you'll need motor mounts, you'll need the specific 64~66 V8 centerlink, you'll need to figure out exhuast, and likely need to swap out your radiator. swapping over to cable style accelerator pedal/operation or hunting down the correct rod and ball linkage for V8 (which F that noise), notching the transmission cross member for dual exhaust if that's your jam.
so again, the answer swings wildly on how much you are able to do yourself, what parts you have or have access to, where you're willing to compromise, and what type of build you want to do (mild to wild).
so, just for the sake of conversation, and i'm going to use round numbers here, let's just say you can scoop up a running 360/727 off of ye olde list of craig for $600. you'll likely need to change the oil pan & pick up so there's a hundo. score some motor mounts at yard for 30 and insulators for another 20 or so. nab a centerlink in the classifieds for a bill, turn up the pedal and throttle cable assembly for maybe 50. you'll probably want to go with dakota manifolds for exhaust, that's the cheapest and easiest option, so there's another $100 (or spend big on good headers at 800 or so bones) and shove another two hundy at the exhaust shop to hook them up and run some pipes and cheapie muffs to the axle and dump there. and then you'll need a radiator so pop for a cheapie alum jobber, there's 250 and throw another 50 at hoses and things and stuffs. hopefully you scored a driveshaft somewhere along the line, or at least got a yoke with that 727 you picked up because you're going to need to shorten the shaft for the longer trans. so there's another 200+ for getting your driveshaft hooked up. you'll need a shifter so let's go low end and hit the swap meet and get a B&M unimatic for like a franklin. okay now let's just add a $500 line item for shenanigans, chicanery and tomfoolery: oil, filters, fuel line, clamps, wires, hardware, connectors, stuff you break, beer, beef jerky and delicious triscuit crackers.
so, that's *checks math* about 2300 that we can more realistically call 2.5K all day.
and this supposes that *everything* on that motor and trans are in good working order and you're not getting nickle and dimed to death on a water pump here, a distributor there, a new set of intake gaskets, or, like, your friend big nose bobby coming over and drinking a 12 pack of your good stuff.
this would be an absolute bare bones, all the stars aligned moment, you lucked out on some smoking deals and hustled your *** off scrounging parts.
