Put that motor in mine Man! Light Hamster wheel in a light cage, It's a match made in heaven. LOL.

Off the engine topic at the moment and for the record focusing on the 64'-65' B-body crowd, I weighed the two extra factory steel sedan post doors that I now have.
With absolutely nothing in them and just the shells, they both weighed in at 77 Lbs for the pair or 38-1/2 Lbs each.
I gather my doors are somewhere in the park of 30 Lbs each. Still heavy in my book.
Oh well, back to this engine feathering that has spawned some rather interesting facts and or fictions.

Ummm... 'extra'?

Only the shadow knows.
Actually the mounted doors are already lightened, but there is more to do.
Diplomatic discussions in full affect. More later.

http://store.alternatorparts.com/repair-kits-and-upgrade-kits-5.aspx they also can provide a kit for you to perform alternator upgrade for round back as well as square back

Before cutting my post doors they were 78lbs each complete with door trim panels and glass.
Doug

Yeah, I did not weigh the doors with all the amenities in them, but glass, glass tracks, side wing glass and their tracks and hardware, cranks, rods, lock strikers, handles, cam wheels, interior panels, seam sealer, sound dead and flash undercoating can add as much as it needs to come up with 78 Lbs per door.
The steel door hinges I know weigh exactly 11-1/2 Lbs for all four.

What did you make the round braces from? Looks like it might be tube

Solid round stock aluminum. I heated the ends up to just a tad above hot and hammer worked it on an anvil to create the flat ends in order to drill out and mount.
Here's a better angle. Been on for years and working flawlessly.

So I've been lurking a while and have digested a little over half of this thread.

I'm sure most guys know this but in case some don't the fender extensions on the Dart fenders came in two varieties from the factory one a pot metal version which my 72' Demon had and one a lightweight plastic possibly 'glass version. There is quite a bit of weight difference if you can find the light ones. The ones I found were on a set of 71 Dart/Demon fenders.

Thanks for quick reply Lee

Are you talking the very front extensions by the headlight buckets? Never knew this.
Long time back I almost went with a Demon as a contrast to the ever so more common Dusters. Though I love the Dusters and believe the Dusters are lighter by a few, I can understand the pickings.
I know a guy who's lightening a 73' Dart but in all the wrong places. I cringe when I look at his HEAVY bumpers and he is looking at taking a small bracket off the rear instead. To each his own though. At least he's having fun as we all are.

Feather Duster linings is what can be rather trick, though limited to certain years.

Yep that's the extension I'm speaking of.

Had a 70 340 Swinger and a 71 340 Demon, both had fiberglass extensions, 71 /6 swinger had pot metal...I have toyed with the idea of making molds for fiberglass ones...

In looking at the pics of the under dash area on Lee's car, I got to thinking about wiring. I know wiring has been mentioned here but just to bring it up again...

I removed any and all unnecessary wiring in my car but had to add some real heavy wiring for the battery in the trunk. I really tried to look and see where I could eliminate things that were not in use like the ash tray stuff, map light, rear defrost stuff, etc. I removed the unused wires and terminals from the junction block and fuse box, they were not cut out with the terminals left in place but removed intact.

You wonder if something like a Painless harness would weigh less? The factory harness has a lot of tape wrap, terminal connectors and associated bracketry to keep it in place. Even if a circuit is not used, the wiring is often left in place since it's tied in to the rest of the harness and can be a hassle to remove.

Just thinking out loud, not sure how much actual weight you'd save and whether it would be worth the effort/cost to change what's there now. Probably nothing close to pounds, more like a few ounces. If starting from scratch, I would think an aftermarket harness would be the way to go but retrofitting one into a currently working system would probably not be worth doing.

Also, using relays allows the use of narrower gauge wire.

RMCHGR, Did you get a good laugh after seeing my spaghetti farm under the dash?
Good points and depending on the car and its options, the extra wiring could add up to maybe a pound at most or ounces as you stated.
I've given serious thought to cleaning up, eliminating and rerouting wires under my office dash for years now, and it's about time I do so. This Winter, schedule permitting, I will go under with the solder gun, electrical sealing tape and clippers in hand. It's almost like deep sea diving under there on your back, even if it is as spartan as a Bachelors refrigerator.
I guess this only matters to those that have been down the chain of every weight loss idea, but ounces do mount up eventually and that leads to pounds.
I particularly love this comment by RMCHGR because it only cost a Summers afternoon and some pizza to achieve, plus I love a clean managed under dash.

I presume since I saw you said you wish you had known about C/M sub-frame connectors and then said that the driveshaft loop tube and crossbar were C/M that it is ok to weld these two materials together?

ALso what are the Heim joints in this pic doing? and what is the zip-tied black thing around the trans?

Starting with the last moving forward, The tie down strap-a-thing is the residual runoff of the retaining strap that holds down the Kevlar trans shield. The first trans shields CSR or CRS or Rcs or what ever they are called were not well planned with their strap buckles and overhang material. I hate having that stuff hang in the wind. Always get stopped by tech.

Heims are part of the forward/backward restraining system since the motor sits with a motor plate upfront. The heims allow for limited movement in most directions during launch to lesson stress but keep things in place. They are 7075 aluminum to keep weight to a minimum.
CM can be welded to steel, just by the right welder using the right welding rods,heat range and oxygen cleansing.

Also, not naked to the eye, the top of the drive shaft loop is inter-welded with the floor adding a little more rigidity to the chassis.
Welds throughout were planned accordingly to their respective materials and stresses.
I grew tired of the bubblegum, rubber bands and Elmer's glue holding things together. LOL

If you want to make your head explode, consider that solder is LEAD and if you start soldering and taping enough wires... well you get the idea. The factory used those mega splices in the dash harness which are small lead bricks.

I actually stopped soldering everything in my wiring projects. I've had it crack and cause more problems than it's worth, even when done properly. Good crimping technique and heat shrink tubing should generally be all that's needed. Most of the factory wires and connectors were just crimped and lasted 50 years if things weren't subject to wayward hands or neglect. Sometimes solder is needed in spots of course but if I can avoid it now, I do.

Last fall I replaced the entire dash harness in my truck, from the bulkhead to the fuse box and everything in between. Not a whole lot going on in that thing with creature comforts etc., so the harness is pretty bare bones. All of it together I'm guessing had to have weighed somewhere between 5-10 lbs? Not sure. But yeah, like you said, with more accessories and options it'll add up. I think guys will take out the accessories and what not but probably tend to leave the harness in.

In contrast, the wiring harnesses in modern cars dwarf what's in our '60s-'70s iron so be glad we're not dealing with it on such a huge scale.

Real-world cost aside, my next project will likely have an aftermarket harness. It's not worth the time and effort in dealing with old, corroded and bent terminals, cracked insulation and old tape adhesive. Plus, you don't add what you don't need so there's no excess baggage to deal with.