I just came in and saw your response. Take a look in my pic, the orange circle is where the lower bolt of an 833 would be. I didn't catch the measurement, I'll try and get it later for you. This is a 383 on the stand now. Just need to ge the fuel system and electrical fab'd up and we should be off and running. I have a 440 to do next, so that'll be easy as all the major work of setting the engine is done. Hope this helps.