Well i got a 95 318 and it had the same style pistons as the 360, Don't know if anything changed in the previous years.

The 5.9V8 pistons withe the oval soap dish increase “tumble” ( or barrel motion )

The original flat top 5.2 pistons probably had superior squish jet effect.

Original 5.2 pistons seemed to be slightly less than 20 thousandths in the hole

5.9 pistons seem to be slightly more than 50 thousandths in the hole.

The 5.9 needed a custom cylinder head design.

Defiantly not factory pistons. From about 1972-2003 they had a flat top with no dish or valve relief from the factory.

It was all about the NOX, no other reason for the 5.9 to have that dish, a KB107 style piston and about .035 piston to head clearance would have been perfect.

“Fast Burn” does slightly decrease NOx,
so yes a “oval racetrack” shaped cavity that concentrates “Tumble”
would both reduce compression ratio, pinging,
and reduce NOx.

The original 1994 iron V10 truck engine used those same 5.9 V8 soap dish pistons “as a cost saving measure” according to Willem Wertmann.
I wonder which engine size had the lowest grams of NOx per mile ?

I suspect the 5.2 V8 has the best brake specific fuel consumption.

First year 5.7 V8 claimed “6% better BSFC”

Well it don't do me any good on this build but it looks like the 03-08 5.7 hemi 2.0" intake valve would almost drop in with a seat cut and finding a spring to fit the smaller retainer (possibly a GM 3100 V6 spring with very mild cams). It is just a tiny bit longer, maybe .020"

On this engine the larger diameter would mean less shaving of the heads and less compression, the bigger diameter, lighter valve and retainer would give me a little more power but I am after crazy compression.

It is worth being “crazy”
but only about “Dynamic Compression Ratio”
and maybe even more important
“Dynamic EXPANSION ratio”

BLM
“best lobes matter”


“Best return on Investment” MPG teaks
are still most likely to be aero and tires.

It is best to maximize compression and expansion ratios. Compression ratio is probably realistically not possible to go any higher than about 10 to 1 dynamic compression even on good premium pump fuel with the best possible fuel atomization and thermal management plan but the expansion ratio can and should be be as high as possible so my plan is to retard intake valve timing to keep under that dynamic compression and make expansion as high as I can figure out how to with a last possible degree before opening the exhaust valve. Since both valve timing events need to happen much later than stock I should be able to simply retard the stock cam and get what I am after for the most part.

As for tires I can't do much compromise on them, I need some mush for driving on dirt roads a lot.

As for aromatics I am trying to find some sort of sheet plastic I can use for blockingoff some of the grill, building belly pans and such right now, it doesn't help that I live 100 miles from a city of any sort. I would bet the biggest amounts of fixable wind drag are from underneath the truck. I might do an experiment with 10 foot of plywood running from the top rear of the cab sloped down to the rear edge of the open tailgate, this should be a very dramatic improvement but could not be left for real world use however it should let me know if there is much to gain from aero. If I did this I should be able to drive with less load witch means less engine heat produced so I can block off even more grill. I can even do this while gathering parts for the rest of it.

I think I am going to get some EQ heads but I got to finger out a time to drive 100 miles in the opposite direction I normally travel to go get em before he sells em to someone else.

https://www.youtube.com/watch?v=E0ass_AxloM

pickup aerodynamics. its an FU 150 but the idea is the same.

HRD, I am not sure if this unit would work on our obd1 trucks or not. Guess it depends on whether or not our crank sensor is inductive. It appears to be a simple way to add some cruise timing to aid the fuel mileage.

https://www.ebay.com/itm/224879329155

That's interesting for sure... I have noticed these magnum engines the timing jumps all around at idle, every one of them jumps continuously around 5 or 10 degrees just sitting idling, I wonder if it could somehow stabilize that? It shows up both with a timing light and on the scanners data stream on every one of them.

I have seen the timing jump your talking about on LA engines with worn out timing chains.

Never put a light on a magnum engine though since the computer controls it all.

I wonder if a timing chain tensioner would correct most of it?

This is by design and is how the PCM micro controls the idle RPM as the IAC can't react fast enough for minor adjustments.

Interesting.

Timing jumps around a lot at 1600 rpm level highway cruise too,
On an Actron Scantool I have seen it vary from 35 to 45 degrees btdc
when the speed in MPH seemed very steady,
but EGR was flowing

Is it something that can be tuned out of the system with a custom SCT tune?

It's not the timing chain for a couple reasons... for one when they were brand new trucks I used to watch them do this and figured it was to give them a rumbly exhaust note but I also noticed they did it at cruise on the scanner. The other bigger reason you know it is not the timing chain is it is being triggered directly off the crank shaft not any thing driven by the timing chain. I bet if you could somehow stabilize it at cruise and idle near the higher numbers you would notice an MPG increase from that. Maybe you could put a regular distributor in with about 18* idle, 35* mechanical and about 10* vacuum advance then figure out a way to trigger the cam sensor and so bypass the computer control of timing but still keep it there squirting in fuel.

That would never work. The factory ECU would pitch a fit without some kind of modification to its firmware. I would just replace the ECU altogether at that point unless you need it for transmission control.

This thing is also compensating for emissions. Replace outright or flash it if that is even an option.

Well I did some aeromatics experiments lately with it and didn't find much (although it was not extremely scientific I admit)

I blocked off about %60 of the grill with cardboard inserts and was planning to remove just enough to keep it from running too hot but it never went over 200 F with the AC blasting in 93 F heat up a 3 mile long mountain grade so I never ended up removing any. I also blocked off most anywhere air was still entering the grill could sneek around the radiator instead of thru it including the air going into the air dam openings. I made some cardboard triangles to go on the front of the mirrors and put some tape over the cracks around the headlights and stuff in the front. I also made some cardboard "air directors" underneath the truck to smooth airflow around a few of the biggest objects like frame pieces and such....

I was trying to just do stuff I was wiling to live with if it worked and I could make more permanent stuff but for all that work I gained about 2 MPH coasting down the 3 mile mountain VS before the aero mods and maybe 1/2 MPG if I round up a little on the 200 mile round trip I have been making 3 times a week. A couple aero things left I would like to try would be basically a full belly pan but have yet to find a suitable material, thinking about robbing some Prius belly pans at a JY because of the way the air extractor holes are made on them. I also have contemplated a temporary ramp reaching from the rear/top of the cab all the way down to the rear edge of the lowered tailgate but so far the only things I have come up with would be pretty heavy... would just be for experimenting anyhow as I use the bed a lot and need easy access. Other than that I will make some permanent grill inserts out of a black plastic tote and uncover just enough to keep things cool and ditch the cardboard underneath.

It is worth studying what GM found and patented about covering only about half of the open bed, strangely from tailgate forward:

https://patents.google.com/patent/US4573730A/en?oq=4573730

A professional aero guy would suggest that you should tape 5 inch long strings of yarn on the outside of the rear window, inside the bed, and across and down the tailgate. Then find someone else to coast your truck down the long hill while you video it. The video should show signs that you have a horizontal “whirlwind” behind the rear window, and a second whirlwind behind the tailgate. These whirlwinds “break loose” every so many seconds, followed by a new whirlwind forming. You want to make mods that “ lock the two whirlwinds into permanent attachment.” When the whirlwinds stay in place they create an “invisible sloping camper top” .

The V12 SRT Rams had blacked out front grille blockoff plates that removed at least half of the opening.

For your own education, coast down your hill with the mirrors folded flush against the side windows.

If you were a weird risk taking coal miner
you would coast down your hill with a tire air pressure 10% higher than max rating, but only on a dry day with nearly no traffic.

I did not know this until recently, but when I read Wheeler’s US Patent I found that he states that labeling tape with capital “V’s” impressed side by side function as tiny vortex generators. This might be an interesting experiment on mirror back edges, and perhaps where the glass windshield” meets the metal roof edge.

Why not try a deeper front air dam that is flexible, and perhaps a second, third or fourth dam placed underneath the truck, instead of an underpan.

Examine the “front spads” that some SUV’s have that block only half of the rear tire width.

I am now 90% convinced that a lot of the odd shaped rear brake light lens designs
are that shape to hold a whirlwind stable and attached.

With your junk yard connections could you get a add on overdrive unit to experiment with?

If you succeed at aero power reduction,
you need engine rpm reduction to get full benefit.

Just read about this new device:

https://www.cyclingweekly.com/revie...est-handlebar-mounted-wind-tunnel-so-far

but $900 is not “cheap” in my thinking,
even allowing that full vehicle size wind tunnel pricing is $500+ per hour