VincentVega is correct. This is not a one size fits all project. Each vehicle will have its own unique dimensions and issues that will need to be addressed.
When I built my 54, I began with a copy of Tex Smiths How to build a Chrysler Plymouth Dodge Hot Rod copyrighted in 1990. The book has been out of print for several years. The article is titled "A Mirada Subframe Into A 53 Dodge Truck" (A Mirada subframe is the same subframe as the Volare, 5th Ave, & Diplomat) and begins on page 62 of the book. From that article, I had to make modifications for it to work on my 54 truck. Following the given measurements, the steering column angle was too sharp, the firewall cut out was too small, and the suspension was too low. (even lowering the tubing into the frame 2", it was still lower then it should have been)
from the measurements in that book.

To summarize the article:
They set the truck on jack stands, [there was no info on how the stands were positioned or how the height was determined] removed the axle & springs, then cut the frame off 11" in front of the front cab mount (I cut mine off 13" in front of the cab mount, but not at this time, it set the front wheels forward in the wheel openings, but gave a much better steering column angle.)[2 things to check before whacking your frame, position of the wheels in the opening, and steering column angle]. After they whacked the frame, the did a "test fit" of the "loaded" K member. Then they used 2" x 4" Tubing to join the k member with the truck frame.
The over all length of the tubing is 26". Measuring forward 7" of the rear portion of the tube, they welded the tube to the top of the frame rail (the 7" mark is the end of the original rail, 7" of tube will be welded to the rail). [This tube position in relation to the original frame determines the ride height. I cut the top frame rail flange off, and dropped the tubing down 2" into the frame (I could have easily gone 3" deep or even completely inside the original frame). Doing this will raise the front of the truck. (Do not assume I have confused the positioning of the tubing and the frame rail and what the end result will be!)
Before everything was hacked off, and welded up, there are holes to drill & cut in the 26" long pieces. From the 7" line, coming forward 6 1/2" is a center line for a 2" diameter hole that must be cut through the inner side of the frame extension to permit access to the k member mounting bolt. On the bottom side of the tubing, a 5/8" hole is drilled at the center line of the previously mentioned 2" hole. This 5/8" hole is for the mounting bolt. There is also a clearance notch that has to be made to clear the K member on the bottom outside part of the frame extension. At this point, they welded the 26" long tubes to the frame and boxed everything in.[I did not, and would not suggest you do the finish weld this at this time. I did tack those extensions to my frame.] Then they bolted the subframe to the frame extensions using the original rubber mounting pads and bolts. [the k member will need front support while doing this.]

The second section of frame is made of 2" x 4" tubing with a clearance notch and holes drilled for access for the mounting bolts. The note said ("see accompanying sketches for exact dimensions") of which no sketches existed. The poor picture showed a notch about the size of the rubber mount cut into the bottom and boxed in, then the 2" holes & the 5/8" holes were drilled. You will have to use your K member for the hole dimensions.
The "new extensions" are installed with a 2" offset to the outside. [and welded and boxed] The K member now bolts up to the frame extension just as if Dodge designed it that way. Neat! [ Yep, after you finish up what they started.] There are many poor blurry, small, black and white pictures, and several more 1/2 truths concerning the rest of the swap that followed my summery.
Once I got the measurements I needed from my K member and transferred then to the tubing, I welded both extension pieces together and did the boxing of the extension pieces joint. Then I bolted both extensions to the K member and positioned it where it needed to be and tacked the whole subframe & extensions to the frame rail, installed the tires, and set it on the ground, set the motor & trans on top of the K member. bolted the front sheet metal to my cab and determined what needed to be changed for the correct ride height and steering column angle and what would be an acceptable tire to wheel opening position, then took everything off the frame, made the required changes and tacked the subframe extensions on and mocked up everything again, until I was happy with what I had. Then I blew everything apart and did the finish weld and boxing and added the front crossmember. Then I pulled the cab & painted everything up.

I found some pictures of the finished frame. Gene