Quote Originally Posted by S10Wildside View Post
A recent customer received a 1998 K1500 pickup with a RamJet 350 crate engine and MEFI4 controller. Here are the before/after (MEFI4/24x) results of the (SuperFlow) dyno runs.

Now to be fair, the MEFI4 could have been recalibrated. But this is what GM gives you (in blue) with the RamJet 350 crate engine.





Did you check the A/F readings? I'm willing to bet if it was a stock tune, it was so rich it would just about be able to get out of it's own way.

I've check 4 MEFI controlled engines, 2 had the Mefi3 the other 2 had the mefi4 controller and all 4 were so rich, they would not even register on my gauge's, until after I flashed them with a properly tuned bin file.

I know Mercury does this so they want have pay for rebuilds, on these so called racing motors.