Well - one would assume they are a streetrod type of product, but they show as an A-body application on Hedman's website. A bit misleading IMO.
The biggest mistake I made was spending the extra cake on the ceramic-coated version. The exhaust installer felt they could be made to fit better & be less restrictive by cutting off the collector flange & weding in a ball & socket adaptor.
...Unfortunately that would have ruined the coating, rendering it useless.
I bought the things as a cost - effective alternative to tti's which are over $1000.00 here. I'm not making huge horsepower, so I felt the shorties would work just fine.
Unfortunately, after the exhaust guy spent almost a day screwing around trying to install the things, they ended up costing me more for his labour.
You will need a mini starter for them to fit at all BTW...
Save the money & buy the tti's.