Couple weeks ago I became the owner of a '92 F-150 Flare Side, 4x4, 351W, that needs an underhaul (Main and Rod bearings, new oil pump, gskets, rear main seal etc). It has both EGR and Thermactor systems on it, that will not be going back on when the engine is re-installed. I'd also like to add headers and a couple other things while I'm at it, and I want to optimize those changes by tweaking the ECM tune. What are my options?

 

You don't need a tuner for those minor changes but investigate the Moates Quarterhorse if you're dead set on getting one, that is one of the few that could potentially work.

Thermactor system can be completely remvoed without issue but the EGR will cause you some problems, it can be defeated by simply removing the tube and inserting a blockoff plate between the valve and intake, but to keep the CE light off it has to remain connected and functioning normally.

 

Thankya!
Now you've got me thinking, can I just put a block-off plate between the EGR valve and the intake, leaving the tube & valve in place, and keep the CE light from coming on?

 

The EGR function can be disabled with tuning software to keep the CEL from coming on.

What are the "couple of other things" you plan to add?

 

I've been thinking about a better set of heads, and maybe the Edelbrock intake and upper plenum if cash allows. I've also thought about the possibility of a scoshe bigger cam, but idk for sure.

 

You're going to need tuning with heads and a cam. You can get by with an adjustable fuel pressure regulator for heavy throttle conditions, however, it's likely that you'll still experience a noticable tip-in-lean condition.

 

Something I've also been hearing about in passing is a Mass Air conversion. In all honesty, I don't know a thing about this, and would it be a worthwhile change, or not really necessary for what I want to do?

 

Yes it would be, however, these kits are hard to come by for electronic transmissions and you'll still need some type of aftermarket tuning to dial it in. However, if you have someone local that can tune speed density, and you have the right cam, speed density can run it.

 

Alrighty. I don't want to go very big on the cam, just something that'll flow better than stock, and compliment the upgraded heads well. If I were to stay within those limits, Speed Density would work fine, correct?

 

Yes EGR can be defeated as you suggested and if the valve remains connected to both vacuum and electrical sources the CE light won't come on.

And as indicated the SD system can accomodate some performance upgrades and if you do nothing else I strongly suggest swapping the cam alone as it is easily the biggest bottleneck to performance with your vintage motor. Better heads would certainly help raise the total potential of the motor and so would an intake but combine all 3 and you could end up not only outside the stock computers adaptive range but also the stock fuel systems supply limits, and that's when things start to get really expensive. If you were picking two items to change I'd suggest the cam and heads since they're harder to get to and you pretty much have to strip the motor bare to do a cam so why not add heads while it's down. Those changes combined with a free flowing exhaust(of course) could net close to 100hp over stock and almost as much extra torque, and if you use an SD friendly cam like the Crane 444232 it'll run just like stock except with lots more authority.

 

Alrighty, cool! I really appreciate the advice both of you guys have given me. Rep points sent! All this stuff I'll definately keep in mind. Also too, what is the ratio on the rockers on these engines? Is there enough piston clearance to safely increase the ratio without changing compression height on the pistons?

 

Stock ratio is 1.6 and you could add 1.7s with the Crane cam mentioned above without exceeding the lift capacity of the stock springs or getting into P-V clearance issues with the stock dished pistons. If you rebuild this motor a switch to flattops with eyebrows is worth the cost just to open the door to heads with bigger valves.

 

Awesome, Thanks!