Sorry Mark, they are still the same, cheap high silicone 4032, which i wouldn't put into a lawnmower.
OPEN CHAMBER - BBC SMALL DOME PROFILE
•Designed to fit Edelbrock STD Series Heads.
•4032 low expansion high silicon aluminum alloy heat treated to SRP specifications
•CNC machined domes with radiused valve reliefs provide optimum flame travel
•Pin fitting and double spiro locks included
•990-2930-150 wall wrist pin (150 grams) included
•CNC Machined ring grooves accept 1/16, 1/16, 3/16 rings, closed chamber accepts 5/64, 5/64, 3/16 rings
JMO
Zip.