I picked up a '66 Coronet 500 in mid June, originally a 318 with air. It came with a 360, 440, and 2 727's. I sold off the 360, the small block 727 and just sold off the 440 this weekend. I've been getting the Super Bee more road worthy and have been driving it every chance I get. Plan 1 for the '66 was to throw the 440/727 with a borrowed 3.91 in it and do it on the cheap, just to get it on the road and enjoy it. Plan 2 was to move the 512 into it from the Bee and put together a 6-pack engine for the Bee, cruise it more. Now I have trouble with the idea of taking a running car apart again to make another one run. I have access to a dirt cheap motor home 440 that is complete, my 727 is just about finished, and I've been through the brakes and installed the 3.91 in it. New front wheel bearings, rebuilt calipers(one has a metric bleeder screw in it. ), new Dr. Diff hoses, all new brake lines, new master cylinder. I ordered new wheel bearings for the rear since it looks like the grease has been washed out of the current ones, and the axles are out anyway.
What have you all done with smogger engines? Change the cam and springs with a Hughes Whiplash kit, oil pan, pickup, mounts , intake and a coat of paint and run it? The thing that held me up from using the other 440 and the motor home engine is the cast crank. The convertor I'm going to pick up is an 11", so I would need a weighted flex plate.
Maybe I should find a 318 Poly, get the air working, and make a daily driver out of it...
I find very few can be effectively indecisive like me.

Can`t help with you with the deciding but my first car was a 66 Dodge Coronet 500 with a 361 BB 727 8 3/4. I will always have a special place in my heart for that car. I wish I had some pics.

My first muscle car was a '66 Satellite that was originally a 361 car. It has a 383 in it at the time. I grew up looking at a '66 Coronet 440 in the barn, so I have had a love for them as long as I can remember. I finally got one many, many years later.

It's better to start with what you want the car to do, in the case of non-OEM-restorations.
Kinda like "a tool for every job", decide on its job first, then build to that.
For example: one hot street car or racecar, one stock, a truck, a late model with AC & such for trips, that kind of thing.
Otherwise what happens is a confused build, or a car you don't use, and money spent you can't recover.

Plans? We don't need no stinkin' plans! Throw in whatever you have laying around and send it down the road!

What I read from that was "Who cares about b-bodies? Get the 340 Dart done". It was hidden between the lines.

Part of me agrees with Rhino. There have been times when I have gotten hung up in planning and nothing got done.

OP the problem is that you have too many available options and you are being paralyzed by the thought that perhaps if you make a choice it won't in future retrospect be the absolute best one.

I highly suggest dropping $15 on this book and reading it - big eye opener and will free you to make choices and enjoy them without second-guessing.

https://www.amazon.com/Paradox-Choice-Why-More-Less/dp/0060005696

Make the 66 run on the cheap for now, and leave the other running car running.

Since you have the rv 440, I would do what you were going to do with the 318 poly. Throw it in and get the a/c working. Also throw in a 2.94 gear so it will cruise nice.

Cast cranks are a lot stronger than you think. I wouldn’t worry about it, unless you had a 4sp. or more than 600 hp.

My first 4 speed car was a 66 Coronet, it had a 383 4 bbl with a 3:32 sure grip. The car was a beat to death car I got as a trade of a beat to death 66 Dodge pickup. I carried forth the beat to death history for the year and a half I owned it. All I can saw was it was a lot of fun. .

Some guy showed up at my place one day and proved to me he wanted that Coronet was worse then I did, so I let it go.

My point is, sometimes, having a car you have little money in, that you can actually drive it in any way you want at any given time is worth its weight in gold! Unless you are in love with that 66 Coronet, put it together cheap, and enjoy the drive as often as you can. I'd probably ditch the 3:91 gears though, but that might be just me. The 3:91s would detract the highway driving experience too much, and would probably add to the broken parts list, and the local police donation society. Gene

I drove a 66 Coronet 440 with a 440 in it for two seasons while my Bee was tore apart for restoration. It was a CA car and pretty fun to do burnouts it. 3:91 gears.
440 powered the car quite well. Other than this I have no input.
KID

Well, that goes without saying as it is the most obvious choice...

I actually really like that body style and would probably decide to retire my 2000 Durango and put the 5.9 in that car...

It came with a 2.94 gear, the 3.91's are on loan. I was less worried about the strength of the cast crank than the anemic compression and the weighted flex plate.(I have a standard plate, just not a weighted one)

This is where the real confusion sets in for me. I really like the car, I've wanted one since I was old enough to know what a car is because of my dad's car. I don't mind throwing it together on the cheap and enjoying it. But it would likely be a go-for-ice-cream locally more than a highway cruiser. The 600 HP big block is in my Super Bee with 3.54 gears and a 30" tall tire. It is bearable on the freeway with the 4-speed.
My most common vision for the car is a cruiser. A decently powered injected big block with air and a 3.23-3.55-3.91 gear with a Gear Vendors or a 518. Maybe a single turbo. Something that handles well, looks true to the era, and will hold its own on the freeway or the occasional 1320 pass. I just don't think it is the right car for me to try my first Gen 3 swap in. It needs a fairly efficient big block in it. Maybe just driving it and enjoying it is the best route to go for now.

Another reason for its purchase. Giving the Bee some down time for some much needed metal work, interior work, engine touch ups(and possible upgrades). The thought was to put the 512 in the '66 and do some work to the Bee. But that may be a bad idea, as I don't think I have a rotisserie restoration in me, and I don't want it down for 10 years while I piece it back together. Plus taking a car apart I can hit the key and run down the road in seems like a bad idea to me.

I say get it driving and enjoy it. I love that Coronet body style very much by the way. Do you have kids? I ask because some of my kids favorite times they still remind me of is when they were strapped into the 5 point harness in my old Dart. Even in a car seat. The memories made are priceless. No kids that's fine as the memories made just driving the car will last forever. Stay simple on the build. Nothing better than nice cool weather. Put the windows down and enjoy the thrum from the motor. Don't need AC, fuel injection etc. Getting thumbs up everywhere you go is nice. Having teenagers come over when I filled up the tank with the trunk open just wondering what the hell? Then they wait around for me to fire it. Blows their mind.

P.s I ran 3:55 gears. Was awesome to pass another Dart on my way back home from Mopars in the Park on I-35. He was tached out at 60mph. That motor was buzzing!!
I was at 75mph. I believe 3200 rpm.

Sorry, I just had to.

Well played...

I never have a problem getting a plan. My problem is they rarely have substance.