I recently purchased a 68 barracuda with a 318 with Indy heads and slightly larger valves. It was also converted to 4bbl carb. My issue is i used have no issues with power braking and breaking the back tires loose. It's not something i do often but just curious to see if it would. I tried again a few weeks ago and it wouldn't spin but once i lifted my foot off the brake it would chirp. I just installed a new cam 285 duration and 480 lift. I broke it in and took it out for a ride it seems to have the same performance. My timing is set around 14-18 degrees. Curious as to what i might be missing. It's HEI not points. Any tips would be appreciated.