Mine is a street car 20 and for what it's worth I just went on Summit and priced trick flow 240s to my door I would be looking at $3160 dollars so that's near 1200 more not 400 and to make what another 20 or 30 hp? I also did fail to mention my dyno numbers were through 1-3/4 hedman b body headers there's power left on the table there too because of my budget.
I wish I wasn't saddled to a budget but honestly if I wasn't it wouldn't take much to wind up in aftermarket block territory as it is.