I bought a 86 Monty Carlo that been build from girlfriend's father he always keeped in garage and when passed away her mother offered me the car and I toke it. And I am trying to find out what size is this motor number are M10069vp
If it's the original motor it;s probably a 305, you can confirm with the casting number at the back of the block where the transmission bolts to the engine. as far as i know those second generation Monti's only came with 2 engine options , a v6 and one v8 the 305. casting numbers at the back will tell ya what block you anyway....