I had a similar situation with my 73. Instead of clogged fuel lines i had a hole that was patched (not very well) with JBWeld. Iassumed the worst and replaced the entire fuel delivery system from the tank forward. Then i bought a new carb just in case i was'nt experiencing enough overkill, lol.
My suggestion (like MEK's) would be a new set of lines from someplace such as Inline Tube or Fine Lines. Until i replaced mine, i had done nothing more than a fuel pump - ever. Even if you remove them in an attempt to blow them out with compressed air, you still have them out so might as well do it right the first time and install fresh ones. I purchased fuel and vapor lines from Inline Tube last January for $160 (more overkill - you should only need the fuel lines so it should be less).
Be in a well ventilated, well lit area when and if you are the one doing the work though :thumbs: Also MOPAR73340 gave me the best bit of advice when i did mine and that was to remove the passenger side rear wheel. Once you've been there it's obvious but if you have'nt...