Did a quick look-see on Allpar ... one of their articles confirm my suspicion ... a functioning EGR system helps improve fuel economy, without significantly affecting performance.
This is another example, as is so often the case, of someone who doesn't really understand what they're doing creating more problems (and worse overall performance) by trying to "shade-tree" re-engineer OEM systems.
From what I can see, if you really, really want to get rid of the EGR, go to an after-market intake manifold, such as an Edelbrock Performer. BUT, that only works on non-emissions-controlled vehicles or in non-emissions areas.
A classic example of people doing what seems like a good idea is found among the hotrodder crowd. They build engines to drag-strip or racecar (high RPM) specifications and then wonder why the engine runs like **** on the street, at much lower RPMs.
They focus on the engine, without taking into account its intended use and the rest of the drivetrain. In following what they believe the "herd" is doing, they stand almost no chance of getting it right.
To demonstrate the right way to approach things, I'll describe what I did with the heads for my current project, involving the '69 Dodge 318 cu. in. LA small block listed in my sig block.
Starting point: I had used the engine for a thousand or so miles, in stock OEM configuration, in the same way I would be using the rebuilt engine, and was satisfied with its performance under typical planned usage conditions.
Normally, I'd just have a "vanilla" rebuild done to stock OEM specifications. As it turned out, I could have used the engine as is, without rebuilding it. When I took it apart, I could not detect and discernible cylinder ridge, indicating low mileage and/or good maintenance. (Most people don't realize their sense of touch is good enough to detect variations of only a few thousands of an inch.)
We haven't measured the cylinders but I'd be surprised if there was more than .005" taper in the cylinders. Most people would be fine just honing and re-ringing the cylinders and existing pistons. Personally, I prefer to bore the cylinders and use new, oversize pistons. (I really hate having to keep messing with things, redoing work I've already done because I didn't go "whole-hog" the first time ... also, when I finish a job, I want things to work/last as long as possible without having to mess with it again for a long time.)
I knew I wanted to replace the heads because, being a 1969, it still had leaded-gas heads, which don't last when using unleaded gas. Also, I wanted to replace the stock two-barrel intake manifold and carburetor with a four-barrel set-up.
Note: Many people are under the mistaken impression that having a four-barrel automatically means higher gas consumption. The venturis in two-barrel carburetors have to be sized for maximum anticipated demand, leading to slightly higher gas consumption during typical mid-RPM cruising. The primary venturis in four-barrel carburetors can be comparatively smaller, sized for the more common mid-range demand. The secondaries kick in to satisfy high-demand situations but are effectively unused otherwise. People's misconception comes from the fact people with four-barrel carburetors have a tendency to "floor it" and keep their foot in the throttle. In contrast, steady, mid-range throttle minimizes use of the secondaries and relies mainly on the smaller primary barrels. (As I've said before, you cannot reasonably expect sports car performance from a much heavier truck ... although this seems to be what people are looking for when they go to high cubic inch big blocks.)
When I chased casting numbers on the original heads and intake, I discovered I had a very rare cold-climate combination that Dodge only offered, as a special option, on very few vehicle for a few years only. Th fact that someone might want them for a unique all-original restoration project is another good reason for leaving them alone and going with different heads and intake. (The heads and intake have to be used together and neither can be used with other, more common, heads and intake manifolds, which ruled out using the heads with a four-barrel intake.)
On eBay, I found a set of unused, military-surplus unleaded heads that had spent over thirty years on a shelf and still had the protective coating the factory applies to prevent corrosion on replacement parts. (Heads were bare, without ever having valves, springs, rocker arms, and so forth installed.) I wish I could have gotten airlines miles for distance those heads traveled. The seller was in Nevada, the heads were in California, and I had them shipped to a speed shop in Maine. In turn, the speed shop shipped them to me in Fairbanks, Alaska, after working on them.
As I previously implied, people tend to do things in the wrong order, concentrating on the engine without considering the vehicle's intended use and other components. As an example of how this perspective leads problems, consider the souped-up pickup truck owned by someone here in Fairbanks.
He put a lot of money and effort in building a high performance engine. He also put a set of big, fat, off-road tires on the rear to handle the engine's expected output. Unfortunately, he didn't consider the components between the engine and tires, like the transmission, driveshaft, u-joints, and rear end. (He also spent all his money on the engine and tires so he couldn't afford to do anything else.)
As a result, he wound up with a vehicle that could barely be used on dry pavement and only with extreme care. Any attempt to make full use of the engine's potential caused the tires to spin or the driveshaft j-joints to snap if the tires managed to get a grip. (He still manages to break a u-joint every few months and, early on, was going through several per week.) Off-road use is just about out of the question, limited to ideal conditions even a Yugo could handle.
In less-than-ideal conditions (i.e., rain, snow, and mud), the slightest pressure on the gas peddle caused the engine to rev up and the tires to break loose. I actually saw him get stuck in a large but shallow puddle on a paved road.
I'll stop here. In my next post, I'll continue with what I've been doing, using a decision process that truly knowledgeable experts say to use to significantly improve your chances of success.
1970 Explorer Class A on a 1969 Dodge M300 chassis with 318 cu. in. (split year)
1972 Executive Class A on a Dodge M375 chassis with 413 cu. in.
1973 Explorer Class A on a Dodge RM350 (R4) chassis with 318 engine & tranny from 1970 Explorer Class A
