440 power, what works

[Sasquatch]

Looking at the Cummins conversion thread at it's 11 pages, there is an interest in repowering our old coaches.  What I want to do here is to offer an alternative for those with 440's.  I would like to share what I did to increase the output and the efficiency of my coach over the last 21 years.  The difference between how my coach used to drive (stock) and how it is now is nothing short of incredible.  Neither the diesel swap or what I am describing here will probably ever pay for itself in fuel savings, but the way it drives will pay dividends. 


My coach (1976 executive 26', 13k lbs) was very anemic when I first got it.  It would barely get out of it's own way.  Climbing the blues, west to east, on I84 (called the Cabbage) from Pendleton, OR heading towards Boise it would have to stay in 2nd gear and pull the hill at about 30-35 mph with the carburetor primaries open wide, but the secondaries remaining shut.  I was in no hurry, and opening the secondaries on the Thermo-quad would only gain 5-8 mph and use a ton more fuel.


With the mods I list below, the coach currently will climb the Cabbage remaining in 3rd gear never dropping below 50 mph.  Fuel mileage ran 5-6 mpg when I started and now averages almost 7 mpg (I have all my old records).  I seldom have to cancel cruise control and drive it myself on all normal mountain climbs normally encountered on the freeway system.


While all these mods took me 21 years to complete, the package works very well together.  The engine is a 440-3, cast crank, 452 heads, low compression (8.2:1 according to Ma Dodge).  The core engine is original with 111,000 miles on it currently.


Here is the mod list.  Each mod made small gains, but once I had them all done the combined package made a HUGE difference.


Cam:  Comp Cams #21-221-4, grind # XE256H
Cam gears: Comp Cams dual roller chain and sprockets, installed in the 4 degree advanced position
Oil Pump:  Melling high volume, stock pressure
Oil: Shell Rotella T6 5w/40 full synthetic
Lifters: Comp Cams stock replacement hydraulic flat tappet
Rockers: Stock/original
Intake: Edelbrock 440 performance dual plane, machined separator web into air gap configuration.
Carb: Professional Products Projection III fuel injection TBI kit
Fuel pump: Bosch FI pump from a 90's Ford F150
Air filter: Late 90's Jeep V8 low profile TBI air filter boot fed by K&N cone filter 3" opening
Distributor: Modified stock.  Limited total advance to 38 degrees, vacuum advance set to manifold, initial timing about 14 degrees advanced.
Ignition: MSD 6A
Wires: MSD 7mm
Spark plugs: NGK tapered seat
Exhaust: Thorley 1 7/8" long tube headers, single 3" Magneflow muffler, exits before rear tires, passenger side.
Cooling: Stock, electric fan conversion removing engine driven fan.  195 degree thermostat.


With the above mods, I cruise pretty effortlessly down the highway and rarely loose more than 5-8 mph on all but the most extreme mountain climbs on the freeway networks.  The engine runs smooth and perfectly jetted at all times.


In another thread I am covering my 4 speed overdrive conversion using a 46RH from a 92 Dodge diesel pick up.  This should take care of dropping my cruise RPM's from the current 3100 to about 2100 at 65 mph.


I hope this helps you all who are trying to find ways for your 440 to run better with more efficiency without resorting to a diesel conversion.  There is no doubt that a diesel will give you better efficiency, but this is a good alternative.

[Rickf1985]

Good write up. The engine mods are pretty much spot on for the big block Chevy's I have built in the past with no complaints. I did not do the injection since it was not available nor did I do the machining of the intake. I like that you mention the single 3" exhaust, I have pushed that for years after doing the math on the flow between that and dual 2 1/2". I am really curious to see how the transmission works into this equation. Now, if you add a Ranger overdrive unit you will have an 8 speed! Hm? Hm? Hm?

[Sasquatch]

I did not machine the intake while I had a carb.  It worked very well as is.  I only did it after having the injection and reading numerous threads on muscle car forums that showed that TBI injection systems prefer an open plenum right below the TBI unit.  Guys machined their dual port manifolds removing about an inch of the separator web between the two sides with great results.

I do not know if I really noticed a difference, maybe a bit smoother.  But it did not hurt.

[Sasquatch]

Regarding the exhaust, it was out of necessity for me.  On the drivers side, where the muffler would sit, is a barns unit for my HWH hydraulic leveling jacks.  So, I could really only use one side of the driveline.  As long as it flows well, I really wonder how much of a difference the tail pipe really makes in an RV that rarely, if ever, runs over 4k RPM.  I think the headers are much more important.  I really do not think I would notice the difference between dual exhaust, single, X-pipe, H-pipe, etc., as long as they each flowed well at low RPM's.  But, I could be totally wrong here.

One frustrating part when researching "go fast" parts is that when you read dyno pulls on engines with mods, most of the time they do not even record anything below 2,500 or 3,000 RPM.  I want to know what the difference is in say, porting vs. non porting heads between 2,000 and 3,500 RPM.  I could care less what happens at 6k, my rig will never see that (well...... maybe once every 20 years or so when my dad wants to try and outrun me in his fancy smancy new diesel pusher...... ).