Ever thought of buying somebody elses project motor complete?? I had a buddy, he bought a show car with a motor (454) with less than 3000 miles and sold it to the machine shop for 600 complete, every bracket everything because he wanted numbers matching, there are a zillion take outs out there, same guy just sold his Novas small block complete carb to pan for $800 with edelbrock heads and new carb, you could drive the thing it ran great, sometimes building a motor is way more expensive than buying a crate or take out, just know what your getting and check it out well, my thoughts of being on a budget, nothing wrong with having to be conservative but building is generally more expensive I have learned.
Heck your talking small block stuff here, its not rare. Yeah my next motor will have roller lifter but do it right if you do flat tappets, check the cam manufacturers recommended oil and break in procedure, not a bunch of strangers on the net, you ask 10 guys and get 10 answers (though those on here are really good) but fact is if that cam goes bald and you tell Isky you did what Joe on the net said they will not only laugh they will most likely tell you see if he will warranty it then and your out at least $300 more. I use a flat tappet Isky( hemi build) and they where VERY clear on what to use, they said Brad Penn, not his break in oil, just straight Brad Penn period, I called and asked about using Brad Penn break in oil and the tech said, did it say break in, I said "No" and he said then don't use it. Use there recommended oil afterwards and drive the hell out of the thing, like we did for 50 years with flat tappet motors with the right oil.....Best of Luck