Back in the early-mid 80s, I worked at a high volume engine rebuilding shop, doing engine Re&Res (including pulling the old engine, strip it down to the long block, clean up all the stuff to be reused (oil pan, valve covers, intake and exhaust manifolds, rockers, pushrods, all the external stuff etc), and bring in the fresh long block, install the lifters, inspect and reuse /replace rockers, pushrods etc as required, set the lifter preload or valve lash, reassemble everything, paint the engine, and install it, break in the cam and set the timing and carb, and do a road test), and occasionally, there would be a problem, cracked head, stuck valve etc, so we would replace the bad head, without removing the intake. Probably did 1/2 dozen engines like that, only 1 FE as I recall, but never really liked the idea, and would never do it on anything again. But it did work, saved some time, and I never personally never had a "come back" from doing so. But back when I was working and getting paid per the job, not hourly or flat rate, you did some things that you didn`t really want to do.
