[SCOBRAC]

My 427 spins nicely to 7200 and makes peak HP at 6250... It has about the same torque as the 428 I took out but makes peak torque at over 5,000. This gives an added advantage of being quite manageable at cruising speed although somewhat frightful at 6000 rpm + That type of thing comes with a price. Big cam, big valves, lots of port work. You really need not go to that length. A nice 427 top oiler and a set of edelbrock heads will get you in the game for $10k or so, less if you build it yourself.

It's all about how you build them. You will spend less than half on a really nice 428 than a 427 however and either way you will be pleased. If you follow the logic the 428 would be a good engine (and it is) a 390 would be good too. Dimensionally identical externally you can build a really nice 390 for $5000 that will easily make 450 hp. But that isn't really the point is it.

I find it quite pleasing to engage in "kit car" conversations with the unwashed masses when they are clearly looking to find fault with my car (and there is pleanty to find fault with) and they ask what engine it has... The 1966 side oiler shuts down this line of conversation pretty fast. Same with the trans. I'd love a 5th or 6th speed but you never need to explain a toploader.

Obviously the better condition, the less use and age it shows the more you might expect to pay.

As for things to watch out for... Old engines mean (generally) lots of miles. 427's do not respond well (typically) to being bored beyond 4.26" or .030". Some have and take it well, others do not. Whatever you get have it sonic checked (for thickness) and mag particle tested (for cracks). Engines at or beyond .030 over are simply less valuable in the long run as they are in the third or fourth bore cycle. Most engines need at least .010-.015 to clean up for a rebuild. A NOS or standard bore 427 will easily be 2x the cost of one at .030" over.

There are new blocks avaliable comercially in iron and aluminum which are far better than OEM blocks, but not original. These are worth looking at and can be had for $3500-5000. Complete side oilers are found for as little as $7500 and as much as $30,000+

Beware of commercial, industrial or boat engines. These were most always taken from lesser tolerant castings, bores not quite square or other had casting issues and were not intended for racing or high RPM use. The 427's found in boats and other pleasure craft are not side oilers. They are 427 FE industrial engines and are not drilled with the side oiling passage.

Service blocks are rumored to be of lesser quality. I find this hard to believe. I'm sure some were, but so were many of the production engines. Ford used a series of paint markings to identify those engines with the tightest tolerances, thickest cylinder walls. The best went to the racing teams of NASCAR and The GT GTP programs, HM, Shelby, etc. You may still find a NOS block with these markings. I have forgotten what they all mean but blue and yellow were the top two.