Without A/C or the other accessories found on conventional passenger cars I could swap engines in under eight hours working just by myself. This would be in a Camaro or Nova with headers for the same SBC or BBC motor. To change engine type took longer because other parts had to be changed in these cars to get a BBC to fit due to the big blocks larger size. In an Impala this is a non-issue. You are changing one SBC out for another. Assuming both use the same water pump and brackets it shouldn't matter as everything unbolts and is reused again in the same place. Change from SBC with a short water pump tp a long pump and you don't have the correct brackets on hand it could be several days to swap it over. Change a transmission from auto to manual and you are adding a lot of shop time as all of the hardware has to be changed over, holes drilled, and pedals added or subtracted.
There are a lot of parts that bolt to an engine, but very few holding the engine in the car. Swapping the engine is easy. Getting it to run again and drive off is the more difficult part.
At a national meet the NHRA gives you 45 minutes to change an engine out, though most choose to just rebuild it in that allotted amount of time. Of course a professional team will have twelve to fifteen crew members working on the car during that interval. Not just one extra helper like 87 year old Chris Karamesines has in his crew on his top fuel drag car. Chris puts me to shame being fifteen years older than me and he is not only still driving a top fuel dragster in national competition, but he is still wrenching on his cars.
By the way twenty years ago when I had my own shop and five employees I charged $250 to swap out a SBC for another SBC in a street/strip car.
Last edited by Big Dave; 04-25-2016 at 12:31 PM.
Reason: typo repairs