Hello!

I think I’ll be buying a car that’s currently built and living in elevation it’s whole life, at about 4700 feet now. I live at sea level.

I plan on cruising it home and enjoying it. I understand it will likely lean out. But is there something I can do on the road to correct this quickly or just baby it until it gets home then rejet and retime it after?

It’s a 400g block with a bore and 455 rotating assembly done years ago.

 

I wouldn't worry about it. Just buy it and drive it home. Once you have her back home you can do a tune up and get her ready to go at sea level.

 

ok thanks!

 

IF the person who built the car optimized jetting for altitude, it will be lean at sea level. Just be careful and check the plugs after driving it a while at sea level. Bleached white plugs indicate too lean. Of course, I suspect that most people have no clue how to properly jet a carb, so chances are it still has the out of the box generic jetting. I ***-U-ME we are not talking about a late 70s-early 80s car where GM sometimes used altitude-calibrated carbs for emissions reasons. And again, this would assume the car was originally purchased and delivered at altitude.

 

yeah it’s an original 4000ft car in 1969. So we will see. It will live its life at sea level here on out so I will check plugs and have jetting optimized along with timing

 

I'm not certain the following quote/information is 100% correct, but I've read this in several locations on the Internet:

 

GM did not use altitude-calibrated carbs in 1969, so if the jetting hasn't been changed from stock, you have nothing to worry about. Of course, E10 runs lean as compared to 1969-vintage gasoline.

 

thanks Joe. Do you know the factory jets needed? Would a 455 rotating assembly and bore (bringing to over 400ci) change the required fuel amount and timing? How would I go about getting a baseline at home and adjusting from there?