I drove the 427R and found it not very street easy to drive. It bucked a lot. Later I was told with an adjustment to the carb that could have been fixed. I ended up with a 427 SRTW #460 and have been happy with it. I did buy my SPF with 1,700 miles on it and the previous owner said he replaced the intake manifold and carb. I have an Edelbrock Air-Gap with a Bigs Stage 5 750 CFM double pumper. Now with over 12,000 miles, I have literally never heard it backfire or miss fire. Every time I've put my foot in it, it just goes. It sounds knarly and I love it. I have noticed when I stick my foot in it, it consumes more
oil. Oh, the 427 SRTW still bucks too much, but none of these Cobras are meant to drive slow. When I'm on the gas it is smooth.