I was in the mix in the late 60's and up untill they killed Jr. Stock class's. Other than three angle valve work and milling to the exact chamber cc's and setting valve springs to allowed height and seat pressure was all you could do. No touching the head valve pockets any where with a grinder. Some port alignment was ok. I once deslagged the oil return holes and they fussed about that.Sometimes I would go through 100 valve springs to find a set that would make it to the 55# allowed at the required hight. The 57 Sedan Delivery 270 hp solid lifter motor would rev to 7200 rpms with fresh springs but after 20 passes it would loose a tenth. New springs would bring it back..My best speed trick was being in tight with the Chevy Dealer parts dept, and got all the latest list of superceded parts. Some of the cams and heads were much better. I was ahead of NHRA on some of them..$6500 in 1960/70 dollars was still way more than I spent unless my time was in the mix...!!! The short block was another can of worms..Racing was fun back in the day !!!
