A833 OD 340 4x4?
In this kind of environment you really need lots of gears, I mean like 5 or 6; then you can apply a smaller engine. Or next best, as I have shown you, is an automatic, with a "hi-stall loc-up Convertor", and an overdrive (like the A500/A518) that works as a 5-speed.
Failing that, you need a bigger engine, to cruise in direct with a low-number rear gear, and still have the low-rpm torque.
Page 1
For economy, the secret is to have a very small engine, operating at very low rpm, at very high efficiency.
For your truck, engine size range is about 2.5 liters(152 cubes), to 7.2 liters(440). Right in the middle is 4.85, so smaller than that could be considered "smaller" and bigger than that could be considered "bigger". The closest V8 (which has 4 power strokes per revolution versus 3 with a Six, which is 25% more, and you gotta have at least 4,lol.) to 4.85 is the 5.2/318. At 360/5.9 you are already over 21% bigger than the median, and 236% bigger than the 2.5........ So, fuel economy is fast slipping away.
page-2
The 360/5.9 can be set up to do reasonably well in steady-state cruising, and it would be my choice for your application. With a two-speed transfer case, you can run hi-way gears, for fuel-economy, yet still have a 2:1 multiplier, turning say 3.23s to 6.46s in the mud. This will get you, at say 5000 rpm and with 30" tires, just over 60mph, in low range. And in hi-range those 3.23s in overdrive, will cruise at 65=1620 rpm with the 30s. That's pretty low; and to do it well will take a short overlap cam and plenty of matching cylinder pressure. But the thing is, now you have both low-rpm torque, and hi-efficiency, with an engine that is of a reasonably "small" size.
Page-3
So hang on a sec
if you had a 440 with say 480 ftlbs at 2000 stall, which would make a very fine 4X4 in high range,, how would that compare to your 360 at 2400, in lo-range? Well I'll bet your 360 with a tiny cam (to satisfy that 1620cruise rpm), would still make 340 at 2400. So in low range, that would translate to 340 x2= 680 out the transfer case.
Now, the 440 might use 4.30s, to your 3.23s so lets kill this coyote; for the 440; 480 x 4.30s makes 2064 into the axles, and for the 360; 340 x2 x3.23s is 2200....... a solid 6.4% more.
So, the bottom line is that you don't have to give it all away, you just have to choose your components carefully.
In your application, now that it is less ethereal, the 360 can, by smart application of gearing, do at least two out of three things well.
And hang on, once more; Lets say you choose an A518. The gears in hi-range are;
2.45-1.45-1.00-.69od.
But you have a 2:1 transfer case.
And lets use the 3.23s for this exercise. and lets drop down to 28" tires.
Ok 65= 1740, a bit easier to cam for.
Your low-range gears are ;2 times each of the gears in the main box, so
4.90-2.90-2.00-1.38
with the 3.23s, we get road gears of ( 3.23 times each of the above ratios);
15.83-9.37-6.46-4.47(in low-range)
If you notice;
4.47 is a good gear to trap the 360 in, making
90= 5320/ 93=5500/96mph=5660/99=5840;
all at 10% slip..........still in low range, but, with the A500 in od.
I think your truck might not make 99 but it might make 90, with the small cam I am thinking of.
To make this work, I am thinking of a solid lifter cam............ a short period, low-overlap, that makes peak vacuum at or near the cruse rpm already established at 1620rpm. And you will have to bump the cylinder pressure to the max for best power results. But at cruising, you want to be able to run cheap gas.
page-4
more coming; I got some errands to run.
I'm back,lol
so at this point, lets recap;
I'm working with a 360/5.9M, and the overdrive Chrysler automatic known as the A500, with a 2-speed transfer case, and 3.23s. Tires would be 28s at the track, 28/30s otherwise, and 30/32s in the mud.
page-5
now we need to build the engine.
Here are the parameters;
> cruises at 65=1740 with 3.23s and 28s in loc-up/ .69 overdrive.
> don't care about power, cuz we got rpm; will be trapping in 4.47gear
> don't care about torque cuz we got gears; 15.83/9.37/6.46; which will get us to 69mph@5000rpm
> aiming for efficiency at cruise rpm.
> must burn cheap gas, without detonation.
First I'll tell you what I would do, then change it up for budget.
as to the cam;
>I am aiming for best vacuum by 1740rpm; so reversion has to have stopped and all the air in the intake has got to be moving in the same direction.
>because I will be running; a modest stall, a wide 1-2 split, and offroading, I need a broad flat power curve; don't care about absolute power; and really care about just having fun. Right so far? So to help get the truck moving in hi-range, to help reduce the effects of the crappy 2.45 x3.23 starter gear, which is what sucks your average fuel economy into the basement, I'm gonna ask for a 2400 stall, to get the delivered footpounds up, so we can get up to speed in a reasonable period of time.
But, the engine still has to make enough power at 1740rpm to actually pull the truck at 65 mph. If it doesn't make enough power, then the roadspeed will keep on falling until you get sick of it and downshift into direct and claw my way back up to 65. And this power has to be made at a small-enough throttle opening so the mains don't get too involved. This is gonna be tough. I've done it on my 68 Barracuda so I know it can be done with a 3650 pound reasonably aerodynamic car. But with a flat-faced truck wearing 30s, hmmmm. IDK maybe 1740 is a lil low. For the moment, let's continue with the 3.23s, so I don't have to redo all the math. But if your truck already has 3.55s, Ima thinking that would be a better choice.
Ok so back on topic;
Ok so first thing is I need a spread-bore carb so that if/when it does get up on the mains, it won't drink all my gas away. Next is the cam. Since this rig is gonna trap in Second at 5000plus rpm with 3.23s, I need a cam that power peaks at say 4800, and that points to a cam in the 215 to 220 range, right on target. So lets look at those. I'll say a 218/226/112
In an FTH (Hydraulic Flat Tappet), you can add clearance rams of about 46 degrees so the advertised will be about 262/270/112, and that points to an Ica of 59* and that will get me around 167psi at 10/1 compression ratio. But-um, I'm gonna run alloy heads so I can pump this up to 185 psi, and so I get that at 10.7Scr at my 900ft elevation. As it happens, the 360 falls together at around 10.7, so this is a no-cost option with 63cc alloy heads. And I have run 180/185 on 87E10 since 1999,lol, so I know this works.
All that very high pressure at low rpm will make her a powerhouse. And I'm pretty sure that pressure will make enough power to cruise at 1740. I know that my Barracuda with a bigger cam, was able to cruise 85=2100/ 65=1600, at a very small throttle-opening..
So to recap what I would run;
> 360 cubes, 11/1Scr, 262/270/112 HFT cam, spreadbore carb on a small plenum modest runner size dual plane, headers yes, cuz this cam still has 42* of overlap, so the headers will help keep the beast moving after 4000rpm, and especially thru the 4800rpm power-peak.
page-6
Now, you may be thinking that alloy heads are out of your reach. But consider what you don't have to spend of sacrifice;
> to run 87 gas with open-chamber iron heads, your pressure will have to top out at 150/155 else you will likely get into detonation. That is a 30% pressure reduction.
To get that power back at low rpm, you will need a cam size at least one or maybe two sizes smaller, or a higher stall, or a lower starter gear, or some combination of these.
To get that power back at high-rpm, you will need a cam at least one or maybe two sizes bigger. or a bigger engine.
Because these two needs are in opposite directions, there is NO satisfying both.
The gearing has already been set, so that leaves more stall/smaller cam. We don't want to go there.
Furthermore, as I said; with 63cc closed chamber heads and say KB107 flat-top pistons, the Scr comes in around 10.7 and the Q comes to .040 with .028 gaskets. Thus saving you the machining costs of; decking, head-milling, intake shaving, possibly porting, and setting up a tight quench. and the new alloy heads already should have a decent valve-job, and probably come with the right springs, and your stock pushrods will likely work. So that's a lot of offset money right there.
page-7
for you now
but hang on; if your current 360 is not burning oil, has decent compression and oil pressure, there is nothing stopping you from leaving it in there. With a 2/1 T-case, in low-range, it will feel twice as big as it is,lol; and the small factory cam will make the best fuel-economy it can at the current cylinder pressure. Yes, with 3.23s it will be lazy off the line, but you can change that with stall. with a lock-up TC you can go sorta crazy on the stall. Every 200 rpm will bring a noticable difference in take-off performance, until you get into absurd-for-street stalls. I myself am partial to a 2800, but I can see a low-compression 360 wanting a lil more; But NOT a 5.9M.
So now we are opening the door to your 5.9Magnum, RAM transplant.
Page-8
now, I know that you are keen to make this a manual-trans truck, but honestly, your options, AFAIK, are too limited and not really conducive IMO, to what you want to do.
If it was me; I might build a custom console, install a manual shifter with a truck stick on it, and-um use my imagination,lol.
page-9
once again, we haven't talked about altitude.
At 5000 ft, NONE of what I have talked about applies.
At 5000 ft you are pretty much limited to starting out with a bigger engine.
I have no idea if an A500/transfer case even exists..........
here is a 727/NP203
That's the second or third time mpg has come up. In which case forget the short-stroke 340. By the time you get decent power out of it, the cam is too big to make decent cruise economy. And if you build it for low-rpm torque, then it won't ET well in the 400M.
In this kind of environment you really need lots of gears, I mean like 5 or 6; then you can apply a smaller engine. Or next best, as I have shown you, is an automatic, with a "hi-stall loc-up Convertor", and an overdrive (like the A500/A518) that works as a 5-speed.
Failing that, you need a bigger engine, to cruise in direct with a low-number rear gear, and still have the low-rpm torque.
Page 1
For economy, the secret is to have a very small engine, operating at very low rpm, at very high efficiency.
For your truck, engine size range is about 2.5 liters(152 cubes), to 7.2 liters(440). Right in the middle is 4.85, so smaller than that could be considered "smaller" and bigger than that could be considered "bigger". The closest V8 (which has 4 power strokes per revolution versus 3 with a Six, which is 25% more, and you gotta have at least 4,lol.) to 4.85 is the 5.2/318. At 360/5.9 you are already over 21% bigger than the median, and 236% bigger than the 2.5........ So, fuel economy is fast slipping away.
page-2
The 360/5.9 can be set up to do reasonably well in steady-state cruising, and it would be my choice for your application. With a two-speed transfer case, you can run hi-way gears, for fuel-economy, yet still have a 2:1 multiplier, turning say 3.23s to 6.46s in the mud. This will get you, at say 5000 rpm and with 30" tires, just over 60mph, in low range. And in hi-range those 3.23s in overdrive, will cruise at 65=1620 rpm with the 30s. That's pretty low; and to do it well will take a short overlap cam and plenty of matching cylinder pressure. But the thing is, now you have both low-rpm torque, and hi-efficiency, with an engine that is of a reasonably "small" size.
Page-3
So hang on a sec
if you had a 440 with say 480 ftlbs at 2000 stall, which would make a very fine 4X4 in high range,, how would that compare to your 360 at 2400, in lo-range? Well I'll bet your 360 with a tiny cam (to satisfy that 1620cruise rpm), would still make 340 at 2400. So in low range, that would translate to 340 x2= 680 out the transfer case.
Now, the 440 might use 4.30s, to your 3.23s so lets kill this coyote; for the 440; 480 x 4.30s makes 2064 into the axles, and for the 360; 340 x2 x3.23s is 2200....... a solid 6.4% more.
So, the bottom line is that you don't have to give it all away, you just have to choose your components carefully.
In your application, now that it is less ethereal, the 360 can, by smart application of gearing, do at least two out of three things well.
And hang on, once more; Lets say you choose an A518. The gears in hi-range are;
2.45-1.45-1.00-.69od.
But you have a 2:1 transfer case.
And lets use the 3.23s for this exercise. and lets drop down to 28" tires.
Ok 65= 1740, a bit easier to cam for.
Your low-range gears are ;2 times each of the gears in the main box, so
4.90-2.90-2.00-1.38
with the 3.23s, we get road gears of ( 3.23 times each of the above ratios);
15.83-9.37-6.46-4.47(in low-range)
If you notice;
4.47 is a good gear to trap the 360 in, making
90= 5320/ 93=5500/96mph=5660/99=5840;
all at 10% slip..........still in low range, but, with the A500 in od.
I think your truck might not make 99 but it might make 90, with the small cam I am thinking of.
To make this work, I am thinking of a solid lifter cam............ a short period, low-overlap, that makes peak vacuum at or near the cruse rpm already established at 1620rpm. And you will have to bump the cylinder pressure to the max for best power results. But at cruising, you want to be able to run cheap gas.
page-4
more coming; I got some errands to run.
I'm back,lol
so at this point, lets recap;
I'm working with a 360/5.9M, and the overdrive Chrysler automatic known as the A500, with a 2-speed transfer case, and 3.23s. Tires would be 28s at the track, 28/30s otherwise, and 30/32s in the mud.
page-5
now we need to build the engine.
Here are the parameters;
> cruises at 65=1740 with 3.23s and 28s in loc-up/ .69 overdrive.
> don't care about power, cuz we got rpm; will be trapping in 4.47gear
> don't care about torque cuz we got gears; 15.83/9.37/6.46; which will get us to 69mph@5000rpm
> aiming for efficiency at cruise rpm.
> must burn cheap gas, without detonation.
First I'll tell you what I would do, then change it up for budget.
as to the cam;
>I am aiming for best vacuum by 1740rpm; so reversion has to have stopped and all the air in the intake has got to be moving in the same direction.
>because I will be running; a modest stall, a wide 1-2 split, and offroading, I need a broad flat power curve; don't care about absolute power; and really care about just having fun. Right so far? So to help get the truck moving in hi-range, to help reduce the effects of the crappy 2.45 x3.23 starter gear, which is what sucks your average fuel economy into the basement, I'm gonna ask for a 2400 stall, to get the delivered footpounds up, so we can get up to speed in a reasonable period of time.
But, the engine still has to make enough power at 1740rpm to actually pull the truck at 65 mph. If it doesn't make enough power, then the roadspeed will keep on falling until you get sick of it and downshift into direct and claw my way back up to 65. And this power has to be made at a small-enough throttle opening so the mains don't get too involved. This is gonna be tough. I've done it on my 68 Barracuda so I know it can be done with a 3650 pound reasonably aerodynamic car. But with a flat-faced truck wearing 30s, hmmmm. IDK maybe 1740 is a lil low. For the moment, let's continue with the 3.23s, so I don't have to redo all the math. But if your truck already has 3.55s, Ima thinking that would be a better choice.
Ok so back on topic;
Ok so first thing is I need a spread-bore carb so that if/when it does get up on the mains, it won't drink all my gas away. Next is the cam. Since this rig is gonna trap in Second at 5000plus rpm with 3.23s, I need a cam that power peaks at say 4800, and that points to a cam in the 215 to 220 range, right on target. So lets look at those. I'll say a 218/226/112
In an FTH (Hydraulic Flat Tappet), you can add clearance rams of about 46 degrees so the advertised will be about 262/270/112, and that points to an Ica of 59* and that will get me around 167psi at 10/1 compression ratio. But-um, I'm gonna run alloy heads so I can pump this up to 185 psi, and so I get that at 10.7Scr at my 900ft elevation. As it happens, the 360 falls together at around 10.7, so this is a no-cost option with 63cc alloy heads. And I have run 180/185 on 87E10 since 1999,lol, so I know this works.
All that very high pressure at low rpm will make her a powerhouse. And I'm pretty sure that pressure will make enough power to cruise at 1740. I know that my Barracuda with a bigger cam, was able to cruise 85=2100/ 65=1600, at a very small throttle-opening..
So to recap what I would run;
> 360 cubes, 11/1Scr, 262/270/112 HFT cam, spreadbore carb on a small plenum modest runner size dual plane, headers yes, cuz this cam still has 42* of overlap, so the headers will help keep the beast moving after 4000rpm, and especially thru the 4800rpm power-peak.
page-6
Now, you may be thinking that alloy heads are out of your reach. But consider what you don't have to spend of sacrifice;
> to run 87 gas with open-chamber iron heads, your pressure will have to top out at 150/155 else you will likely get into detonation. That is a 30% pressure reduction.
To get that power back at low rpm, you will need a cam size at least one or maybe two sizes smaller, or a higher stall, or a lower starter gear, or some combination of these.
To get that power back at high-rpm, you will need a cam at least one or maybe two sizes bigger. or a bigger engine.
Because these two needs are in opposite directions, there is NO satisfying both.
The gearing has already been set, so that leaves more stall/smaller cam. We don't want to go there.
Furthermore, as I said; with 63cc closed chamber heads and say KB107 flat-top pistons, the Scr comes in around 10.7 and the Q comes to .040 with .028 gaskets. Thus saving you the machining costs of; decking, head-milling, intake shaving, possibly porting, and setting up a tight quench. and the new alloy heads already should have a decent valve-job, and probably come with the right springs, and your stock pushrods will likely work. So that's a lot of offset money right there.
page-7
for you now
but hang on; if your current 360 is not burning oil, has decent compression and oil pressure, there is nothing stopping you from leaving it in there. With a 2/1 T-case, in low-range, it will feel twice as big as it is,lol; and the small factory cam will make the best fuel-economy it can at the current cylinder pressure. Yes, with 3.23s it will be lazy off the line, but you can change that with stall. with a lock-up TC you can go sorta crazy on the stall. Every 200 rpm will bring a noticable difference in take-off performance, until you get into absurd-for-street stalls. I myself am partial to a 2800, but I can see a low-compression 360 wanting a lil more; But NOT a 5.9M.
So now we are opening the door to your 5.9Magnum, RAM transplant.
Page-8
now, I know that you are keen to make this a manual-trans truck, but honestly, your options, AFAIK, are too limited and not really conducive IMO, to what you want to do.
If it was me; I might build a custom console, install a manual shifter with a truck stick on it, and-um use my imagination,lol.
page-9
once again, we haven't talked about altitude.
At 5000 ft, NONE of what I have talked about applies.
At 5000 ft you are pretty much limited to starting out with a bigger engine.
I have no idea if an A500/transfer case even exists..........
here is a 727/NP203
