When I built my headers in 2005, I used Hedman slip ons.
Summit had a good price on them back then.
They were $95/pair, but I see they are about $200/pair now.

Weld on collectors are much cheaper.

1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1