They have the cylinder heads to make over 1,000 if you do a max effort with raw castings. The NASCAR stuff was limited to valve size and RPM. If you go to Ernie Elliot's website he says what say you can go ever 400 with a cast iron block. And I know of a 467 CID combo with the aluminum block.

My car with the low deck lightened R3W8 engine with really light internals was 2,950. With the R5P7 cast iron block, dry sump, adapter plate, and alternator the car weighed 3,000. I hope to loose 100 lbs with the aluminum block.

Leon