I'm going to put these on my 317 heads and run the 228/232 cam. Do I need get new spring seats and retainers with a dual spring like this? The engine is fairly low mile but I don't know the exact mileage because I bought it from a core yard.

 

yeap, factory heads have beehive springs which have smaller size retainers. If you want to retain seats and retainers Comp 918's will fit the job.Just drop in and buckle up.

 

buy the entire kit to include springs, ti retainers 144661 and lower spring seat 144460. you can get old stlye valve seals from gm

 

Yeap that too

 

and you can get the kit from here: http://www.vincihighperformance.com/superwebdeals.HTML and while you are at it, you can get the spring tool as well.