[VegasDelta]

Hello Darren, any 425 or 455 will bolt in with the right engine mounts. Toro mounts are different, you'd have to get new mounts or use the same (8 cyl) mounts that are in your '69 now. Also you'd need to change the oil filter mount from the toro because the angle is different. The one from any other modern Olds 8 cyl will bolt on. If you want to use a 4 spd you'll need to have the crank drilled out for the pilot bearing. Olds only did this w/ engines meant for a standard from the factory. A turbo 400 was the stock trans used on a big block, although a turbo 350 can be built to use. A 400 will use a larger yoke & is longer than a 350. Good luck, Jerry.