I really don't know any bads about either engine builder. But plenty of goods.
When you compare the two, you really have to get to the point of what you are looking for. Comparing two 555's and saying which one goes faster in the mph really isn't fair. If I were to compare two 565's I just built, one will stomp the other up one side and down the other. But one was made for a 7.50 bracket Cadillac, and one was supposed to get 1000 passes without a rebuild in a dragster. So there is much more to an engine than mph in the lights. Longevity, possible breakage, etc. Cam profile being smaller and kinder will make less power, but you can go longer without valvetrain issues, and may not need to check the lash that often. I was informed of an interesting point the other day by a Winston Cup builder. He said if I give 10 identical engines to ten tuners, they will all act very different. Therre is much in the tuning. (And performance is also very dependent on the converter. You run a Hughes and you will be down 4-5 mph over a Neal Chance. But Hughes converters are soft, and possibly more consistent on marginal tracks where a Neal chance will lock up and possibly slip the tire a bit.)
Just too many variables. Both make lots of engines and have lots of time and resources to test each application on the dyno. Both have great and knowledgeable people designing and assembling. Both are great at matching the cams to the engine, and matching other parts to the combination. That is where these builders are superior to us. The little guys that do it all in our own shop. They can test 30 cams on the dyno, and have the cam companies make a custom grind just for one engine package. We pick what would be best in our mind and plug it in, or try two or three cams.
That being said, when you compare as close an engine as you can from one company to the other, Scott is about 5% cheaper. That is matching cubic inch, horsepower/torque, parts, brand names, etc. And from there, it is all about bragging who has more passes on theirs, who mph's better, who got the better deal. And that is like trying to argue what favorite color is superior.
I really put Lukovitch, Shafiroff and RM right about the same for what I have seen, heard and experienced. If you are in an all out class, then lets get specific, but for a bracket car, if it makes good power and lasts forever- find what you like and like what you find.
