Another Disc brake hose question

Ok, so, if you mount the calipers to the rear you should not use 73+ A body hoses, you should use the Volare hoses. The A-body hoses are too short for proper hose routing.

As far as the Orielly vs Napa hoses, they're the same length. For the O'reilly hoses you've specified the overall length, and for the Napa hoses you specified the hose length. But both hoses have a metal block and tube for a banjo bolt. The hose length is just the rubber part. Take a look at the specs for each one...

Brake Hose - Right Front
Brake Hose End Type Treated Steel
Brake Hose Length 15.31"
Caution Statement Do Not Use W/ Petroleum-based Fluids - Designed Only For Use W/ Dot Approved Silicone Or Glycol-based Brake Fluids
Gasket Included Yes
Hose End Type 1 Banjo - 0.44
Hose End Type 2 Female - 3/8"-24
Overall Length 17.2"
UNSPSC 40142020

BrakeBest Hardware & Hydraulics BH88971 - Brake Hose | O'Reilly Auto Parts
ADDITIONAL DETAILS

• Color: Black
• Bracket Included: Yes
• Bracket Material: Stamped Steel
• End 1 Fitting Material: Treated Steel
• End 1 Fitting Size (In): 7/16 Inch
• End 1 Thread Size: 0.4375 Inch
• End 1 Type: Banjo
• End 2 Fitting Material: Treated Steel
• End 2 Thread Size: 3/8-24 Inch
• End 2 Type: Female
• Gaskets Included: Yes
• Hose Length (In): 15-1/4 Inch
• Hose Material: EPDM Rubber
• Installation Hardware Included: No
• Jacket Material: Rubber
• Mounting Hardware Included: No
• Segment 1 Length (In): 15-1/4 Inch
• Total Length (In): 17-3/8 Inch

Both hoses have an overall length a little over 17", and a hose length of over 15", just a fraction to decimal difference in length between the two really. Probably the same length in reality, one may have been listed in metric and converted.

For a '73 Dart, the hoses are only 15" with a 12" hose section, and they're too short.
Brake Hose - Left Front

That all said, there are some different styles of hoses out there, and you can't always depend on the parts folks to get you the right parts.