I purchased my 1987 Oldsmobile Cutlass Salon late of 2019 it had the factory Olds 307. I swapped the 307 for the Olds 455 about a year or so afterwards. I kept the stock cam but had changed out the intake manifold, exhaust manifold and carb and rear end differential to a 3.42 posi. I did all of the work myself, it had run decent for a near complete stock engine 13.2-13.5 in 1/4 mile. The machining was done by Conrad Racing engines out of Belville, Texas and my Transmission TH400 I bought from (Doug) Herzog Motorsports out of Warrenton, Missouri. Doug was the one who recommended Conrad racing engines, at the time while I was living in DFW, Texas. Both Doug and Ed, have been of great help and above all HONEST.