[Rick Parker]

olddog:

Be careful with the actual engine you select. Some of the early heads in the Cobra Mustangs had problems with spark plug threads (or lack of them). They used a plug with very few threads and were known to actually "Blow" the plugs out of the heads after the threads fractured. I know of one motor that had a "ticking sound" (like a bad lifter or rocker arm) it turn out to be the weakened threads allowing the combustion charge to escape. The ticking got progresively louder as the engine was warming up.