I am going to make a 3000 mile trip.
How lean can a 350 with a 700r run at 60 to 75 mph without damaging the engine?

Thanks
me2

 

What is your reason for this question? What problems are you experiencing? There are alot of factors involved. RPM, load, etc. Generally 14.7 is stoich, where all the air and fuel is consumed in the combustion process. At cruising speed, the AFR might be at anywhere in the 14.5 to 15.1 or even as lean as the 16.1 range. Having the engine lean in the medium to higher engine loading, is where the problems start.

 

What he said.

U wont find it out until you experiment on your own engine.

Even to seemingly identical factory cars might do best at different AFR's and timing.

Some combinations dont like highway mode and some take to it like it came that way from day one.

I generally add a couple of degrees of timing and start around 15.5 or so AFR when doing testing.

U might have to play a lot to make it happy or see some results or you might see them right away.

Tons of info on the prom board about highway mode and great info in the stickes there as well.

Assuming your car is still injected of course

later
Jeremy

 

Thanks for your help.I will be traveling from Mazatlan Mexico to Fort Wayne Indiana, a 3000 mile trip.This will give me about 5 days on the road to fine tune the accel computer on a TPI chevy 350, 700r with tc lockup and a 3.55 ford rear end in a nissan hardbody pickup. 14 mph realy sucks.

Thanks again for your help,
Me2

 

Sorry for the errow in the post. It should have been MPG not mph.