A 3.3/3.8 WILL NOT bolt up to an A-833 thus the recommendation of the 3.9. While you seem to enjoy insulting me intelligence with your engineering degree and doubting my secondary education. I have over 30 years as a PROFESSIONAL mechanic, ASE Master Tech, 2 year electronics degree and a bunch of other school, classes etc. I was in charge of radio and light control instillation for the CHP through Frontier Radio in Sac in the late 80's, installing over 2000 GE Ranger radios w repeaters and Code 3 light controls in CHP vehicles. I have built hundreds of magnum engines and even more SBC's that have won numerous competitions, been a crew leader for Mazda racing in Playboy Escort Endurance Series in the mid 80's traveling to most major race tracks, been crew chief on 2 desert race trucks in baja 1000, Yerington 400 and 250 and Vegas to Reno. No, I don't go around "blowing my own horn" about my incredible skills as an "engineer". We used to have an old saying, "it takes an engineer to design it but a mechanic to make it work."