The "1070"5 is a mystery - but as stated "CLU" probably started life as an L65, 350 Chevy. Nothing special - 165 horse smog motor built to California emissions standards. Definitely a transplant and the only way to know what you've really got is to do a bit more research. Head casting numbers would be helpful to see if there's been substantial work done or if someone put bolt on rockers and a huge Holley carb on the motor to impress. The 850 is almost certainly way too much for the engine unless you find the engine's really been upgraded..