I am looking for advice on perking up & improving the efficiency of my Club wagon 15 passenger van. I am a motorhead, and understand about engine rebuilds & most common modifications. I am also familure with fuel injection. I havent had this van very long, and plan to use it in a warm climate at high elevation. It will spend most of its time in Mexico, where gasoline costs over $2.25 a gallon, and the air is thin. Yes, I am a missionary!

It is an 88 model, with a 351w, C6 trans, 3.54 gears, and stock exhaust. To me, this looks choked off! It comes off the manifolds with duals, comes into the cat, squeezes into a single into the muffler, then splits back to duals!

EXHAUST:
I know it is COMMON to add duals to pick up trucks, and I know this van is no different driveline wise. I have heard (thanks guys at Autozone) that opening up the exhaust on some EFI engines will cause the exhaust gas to move past the O2 sensor too fast, causing the computer to richen up the mixture & hurt mileage. Any experiance on this matter?

I am also considering Headman headers from Summit, over the stock manifolds. Is anyone running headers on their 351w powered truck/van with true duals & glasspacks (luv that sound!) ? I plan to put on dual aftermarket cats to help keep the air clean. Anybody have personal experiance with a similar setup?

HEADS:
I want to keep the engine close to stock, but know there are a lot of tricks to make them breathe, without spending a bunch of money. I am familure with head porting & polishing, but am seeking advice from someone whos "been there - done that ".
With this being a port fuel injected engine, I am thinking there would be some gains to be had by doing a fair job of polishing the intake port, as well as the exhaust port/runner. I know on a TBI & carb engine, you need to leave the runners a little rough to help keep the fuel mixed with the air.

Also, thinking heads, since the air is thin where this van will spend most of its time, would 302 heads be more practical? I am thinking smaller valves = more velocity?

CAMSHAFT:
I have heard some say the stock cam is best, since I plan to keep the EFI. I am going to look at a performance chip. Any experiance or advice?

The van is going to be used for some trailer towing, people moving & climbing mountains. I am not planning to drag race it, but am looking to wake it up, and have enough punch to get out of its own way, as well as the Dina coming towards me !

I am also looking at "freshening up the engine" with a basic overhaul.

I apologize for the long thread - maybe I can get some advice since I found out where I should post this question

Thanks guys!

 

Well the most noticeable thing you mentioned was the use of 302 heads and quite frankly 80 or so up heads on the 351's in the most part are 302 designs with 1/2" head bolt holes so if velocity is what your looking for you already have it. You could get better fuel economy from a cam change so don't rule that out. I have hedman shorties with true duals and the headers did make an improvement in power however I have a carbed vehicle so there may be some differences in your experience, should still be positive. Are you wanting power or economy I wasn't clear on that one. IF it is economy you might consider an AOD tranny swap that would help more than anything you could do to the motor as far as gaining mpg. Maybe a cam recommended by a cam manufacturer with your intent of more mpg than stock and an AOD would be a good step a little gasket matching and smoothing of the ports on the heads couldn't hurt either. Good luck with whatever you decide

 

Thank you for your advice! I didnt know that about the heads. I have built several carb engines for use at high elevation, and I know how important it is to get the velocity up. We often look for small valve heads to do this.

I have had pretty good luck at building up a "stock" engine with a few performance mods, like opening up the exhaust, port match & polish, and a towing/rv cam, bumping up the timing, running a cooler thermostat & cool plugs to keep spark knock to a minimum. This combination seems to work well for boosing the power AND economy! However, they have all been carburated engines & were Chevy & Mopar. For some reason, we can shove quite a bit of timing into an engine at this elevation, run on low octane fuel & not have any spark knock problems.

This is the first EFI engine I have attempted, and my first Ford I am trying to do this. It looks to have a tall ram type intake manifold & a large 2bbl type throttle body. You mentioned an AOD transmission. Do you have any experiance or have info on the durability of one of these? I have access to one for a very reasonable price, from an 89 Club Wagon. It is in good condition.

I guess I am going after both economy improvements as well as power. I just need some advice. Thanks guys!

 

Personal experience no but it is pretty common to hear that the aod is a decent tranny that can be built up to be strong, in stock form it has its weak spots but as with all things it really depends on how much abuse you plan on giving it. IF your going to the trouble a computer swap or stand alone piece might allow you to put a e40d which is basically a c6 with overdrive and everyone knows a stock c6 is strong behind your motor. All the principals you applied to the carbed motors applies to the efi only difference is when it comes to the cam you have to keep the lobe seperation around 114. IF your looking for a little hotter than stock or an rv cam then your good as far as that goes as most lobe seperations on mild grinds fall in the 114 range, give a cam manufactuerer a call they can set you up with something that will allow the use of a stock computer (114 lobe seperation) and still give you the get up you crave. IF you port the heads and add headers you might not realize the potential until you have a chip burnt you will see a difference but unlike a carb you have to tell the computer it is okay to feed more fuel. Hope this helps out some, shortly you should have all kinds of opinions and perspectives to help you make a decision right for you, Good luck