G'day all, I have a bit of an odd question here... I'm wondering if anyone has any idea what the '88 spec engine is capable of flowing through the EFI plenum.

My truck was running the 1 barrel intake with an Impco 225 LPG Mixer(329CFM max) and I was having problems on the highway maintaining 60mph, I swapped back to the EFI intake the engine came with and a 2 barrel base plate for the mixer (modded from a 302 V8 app). I have great bottom end grunt still, and highway manners are better, 60mph in 5th can be easily maintained with about 1/4 throttle vs. 3/4 minimum with the old intake.

The big problem is that without restricting the air inlet of the mixer it leans out at about 2k rpm under load, no load it stops revving at 3k rpm, lean backfires etc. with the air hat on and the crown vic air box hooked up it leans out under load at about 3200rpm with much less power on hills vs. the log intake. 4th could hold about 50mph at WOT, now i'm down into 3rd gear at about 40mph.

I hope this makes sense to someone on here, main question is, can this 300 really top out the flow of this mixer? If I hit the primer while snapping the throttle it will float the valves faster then I get it back to idle.

Forgot to add some specs on the truck here...

'86 F150 2wd, '88 300 Six, M50D, 3.08 rear gears, 31x10.50R15 A/T tires. Factory EFI manifolds and cats with 2.25" straight pipe.

 

Sounds like a problem to run by the Impco tech people.

 

I'm going to try tweaking the reg. today and see if there is a bit more fuel to be had.

Edit...

I pulled the 1" Vapor hose to fix other problems and found heavy end build up about an inch from the reg that was closing the hose off to about 1/2" internally for about 3"... This is the last time I strip stuff from other trucks without checking them!