6.5 block, 6.2 heads

[jjmoore]

built a 6.5 block with 6.2 heads for my 87 K10 suburban , 700r4 tranny, gears.. need to know what IP to use? and injectors to use . non turbo. I was thinking 6.2 IP and increasing fuel screw 1/4 turn with long injector. i am looking for good fuel milage.. . the motor came with a 2831xx4911 with short injectors. it would blow clouds of black smoke when I floored it to pass cars and ran strong.. now I had to adjust fuel screw to allow less fuel about 1/4 turn ccw to stop black clouds upon acceleration, but have lot less power, to pass cars that was with 3.73 gears and only got 14 mpg. now I have the 3.07 gears and shift down to 3 rd gear to pass and get 19 mpg. any ideas?

[john8662]

1/4 turn of fuel is too much fuel.

Will smoke, will get poor fuel mileage, and will make high EGT's that you're not aware of because there isn't a gauge installed to monitor it.

The amount of fuel your're talking about is to be used with a Turbo.

With that said, I'd calibrate the injection pump for a later model 6.2 J series engine, use the long-body injectors with the lines from the 6.2 engine (since you used 6.2 heads).

I'd take the shift down and 19mpg over the 14 any day.

If you want power and fuel economy, step up to a Banks turbo system.