What I have seen since 1955 re: Chevrolet, Ford, Mopar.
In small blocks Ford started out for the first number of years doing everything it could to screw up. Several different engines...they couldn't make up their mind what to manufacture. I doubt few Ford guys can even remember all the configurations...not so with Chevrolet. Chevrolet started with and stayed with one basic engine starting at 265 ci and continued to build on it. Mopar didn't have squat until the 340. Much too late and too little...the 360s were junk. Boat anchors, and damned few 340s were made, they were never in the picture. Chevrolet unarguably is the engine of choice for hot street cars or door slammer racing when talking small block. Can't be beat unless 3 times the money is spent. In other words you start out with a 50 mile per hour wind in your face to build anything but a Chevy unless you wish to be different and have a really good budget. From both a performance and reliability standpoint. To race a 340 Mopar would require a person to be totally uninformed or a glutton for punishment.
Big blocks: Again the fastest muscle car carried a BBC. 70 LS-6. My pardner owned a 70 Hemi Cuda. Knew better than to do any street racing with me although we raced everything else we owned. The BBC was and is not perfect. But in comparison to a Hemi it is a jewel. Hemis had a soft lower end among other things. The 'splayed' valve angle on the BBC made it breath as well as it needed without the weight and complication of being a hemi. Ever look at the valve gear on a hemi....scary. It should be noticed that few were made and Chrysler droped the engine from production ASAP. Currently if you want to go good in a hot street or door slammer competition you had best buy a Bowtie block BBC. The Ford big block is OK but it will, again, cost an arm and a leg more to make it go as well as a BBC. The Hemi? Unless a guy is in love with them rows of plugs in the middle of the valve covers and has money to spare [a lot] he best follow the path of all them guys that have BBCs in their Fords.
With that rant ending, I gotta say that it is a relief to see something other than a damned SBC in a hot rod/custom car meet. Everybody and their brother has one in their car! And always hooked up to an everyday T350 trans! When I finally find a, say, 36 Ford with a small block Ford I feel like cheering. Small block Chevy motors are ugly. And get worse with all the "billet" BS they buy out of a catalog and slap on them. Worse than Evolution Harleys.