440 build for a tow rig/"muscle" truck?

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MopaR&D

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I hope it's not an issue since this isn't about an A-body but this is still the best place by far to ask any Mopar-related tech questions. I have a 1972 D200 pickup with a good-running 360 but after towing my Duster to the track and back 120 miles away up and down the front range of Colorado on I-25 I realize I want more power. I could get good results swapping in a 5.9L Magnum, overdrive trans and 4.10 gears but I've been jonesing to build another big block and this seems like the perfect application. Current 360 already has 4-bbl intake and carb and longtube headers and does great with lighter loads but it struggles to pull a 5000-lb trailer up a steep grade at 65 mph (speed limit is 75).

The truck is a regular cab long bed and 2WD with a full-floating Dana 60 rear end that has 3.54 gears and a 727 transmission which I will probably stick with for cost reasons (I know I'll need a BB 727). The idea of swapping in a manual is appealing but AFAIK the only one that readily bolts up is the old NP-435 which is basically a 3-speed plus granny gear. Truck weighs about 4600 lbs empty with me in it. I'm leaning towards a 440 with Stealth heads (costs the same as having iron heads machined and new hardware installed) and bumping up the compression to around 9-9.5:1 since I'm at high altitude. However I'm not sure what off-the-shelf pistons would get me that ratio and I also need to keep the quench distance either greater than .125" or less than .045" otherwise it'll be MORE prone to pinging. Also looking for recommendations on a cam, I'm leaning towards a Lunati Voodoo 256/262 but not set on it. For intake I'm thinking Edelbrock RPM, and I was thinking of swapping the 750 cfm Street Demon from the 360 in my Duster to this engine, you guys think that would be too small? Any other thoughts welcome.

Oh and I know gas mileage will be terrible but it currently only gets 10 MPG unloaded anyway so I figure it can't get much worse, seems most guys with 440 Dodge pickups are getting 8-10 from what I see on bookface.

Here's some pics of my truck btw...

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That is a clean little tow rig you got there and i believe the 440 will help but i have had a few big block motorhome's and towed trailers with jeeps and found the hill climbing abilities to be lacking.
I ended up picking a gear for the powerband of the engine and kept it there. Just my thoughts but a Cummings transplant would be the ultimate change up.
P.S. I forgot about the muscle part. It would take a few pounds of hundreds, but it could still work.
 
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I believe you are thinking right, a 440 and tranny for more torque and towing ability. Mild mods w/headers will help more. Your carb should be about right as too large will affect throttle response.
 
That is a clean little tow rig you got there and i believe the 440 will help but i have had a few big block motorhome's and towed trailers with jeeps and found the hill climbing abilities to be lacking.
I ended up picking a gear for the powerband of the engine and kept it there. Just my thoughts but a Cummings transplant would be the ultimate change up.
P.S. I forgot about the muscle part. It would take a few pounds of hundreds, but it could still work.

I agree I would love to put a Cummins in this truck but it would take some money to do it the way I'd want (12-valve and NV5600). If I was being the most practical I'd just swap in 4.10 gears and drive a bit slower when unloaded but... I don't want to lmao I've been looking for an excuse to build a big block for a while now. I wouldn't mind having a healthy (wear-wise) spare 360 either and the one in the truck would make a good builder as it likely has the thicker cylinder walls being a 1972 block.

I know pretty much all the motorhome and truck 440s were very low compression so I'm thinking bringing that up to at least a true 9.0:1 from 7.8-8.0:1 will make it pull better and possibly save a bit of fuel. And the extra airflow from the heads and modern cam will boost the mid-range torque and stretch out the powerband so it can rev higher. One downside of the current 360 is the stock 2-bbl cam, doesn't really pull much past 4000 RPM which limits my speed a bit in 2nd gear.
 
Build a blueprinted 440HP engine, but get compression to 9.2:1. Put Comp's version of the Road Runner cam in it. It has real Chrysler lobes and they narrowed the LSA to 110, from the factory 115. I like the Weiand Action Plus intake. I have one on the 351M in my 75 F250 and it pulls like a ***** in church.
 
Build a blueprinted 440HP engine, but get compression to 9.2:1. Put Comp's version of the Road Runner cam in it. It has real Chrysler lobes and they narrowed the LSA to 110, from the factory 115. I like the Weiand Action Plus intake. I have one on the 351M in my 75 F250 and it pulls like a ***** in church.

Sounds like a solid plan and that cam sounds like it would run awesome, I figured I could go bigger but wasn't sure for towing. Probably make some nice noises too, not really lopey but hard-hitting. And I'll keep an eye out for that intake, I'd like to find something used and save money where I can so having more options makes that easier.
 
Sounds like a solid plan and that cam sounds like it would run awesome, I figured I could go bigger but wasn't sure for towing. Probably make some nice noises too, not really lopey but hard-hitting. And I'll keep an eye out for that intake, I'd like to find something used and save money where I can so having more options makes that easier.
The Street Dominator is another fine intake. While it's a single plane, it gives up nothing on the bottom end.
 
Remember, those Stealth heads have 80cc combustion chambers so you’re compression ratio might be higher than what you’re thinking.
 
Remember, those Stealth heads have 80cc combustion chambers so you’re compression ratio might be higher than what you’re thinking.
They're also aluminum, so he may can get by with it.
 
Remember, those Stealth heads have 80cc combustion chambers so you’re compression ratio might be higher than what you’re thinking.

That's true I have been taking that into consideration when checking piston specs and calculating compression. Unfortunately a lot of the flat-tops I see end up in the 10.0-10.5:1 range with a .051" composite gasket. Something else though is I'm at 5000 feet above sea level most of the time and get up to 8000 feet or more at times so higher compression is required to regain some of that loss which is 25-35% total HP and torque. Forced induction especially turbos are the way to go around here, they have a huge advantage it sucks really for us old-school V8 guys lol. With that said still not really trying to go over 9.5:1 for the kind of load it'll be seeing.
 
I have a 76 short wide with stacks,440 forged pistons .110 down in the hole,440 source heads,9:75.1 comp,275 durration 110 center hyd cam,18 degs initial,38 total at 2900 rpm,750 edel carb,performer rpm intake,727,2400 stall,2.94 sure grip,ac,cruise, best of 12.9 mpg,daily driver,have towed 4600lbs, never lacked for power, ultra-bell 2 months on back order so far have 46rh to build then put the 9.25 with 3.55s back in,
 
@Tbro thanks for the links, I remember following those threads when they were new, super interesting stuff. If I was closer to sea level I wouldn't care about the compression but up here N/A engines need all the help they can get. Since the torque loss from the lower air density is across the whole RPM range you really feel the loss on the low end since the torque is lower there to begin with. Compression will also help with fuel efficiency.

I have a 76 short wide with stacks,440 forged pistons .110 down in the hole,440 source heads,9:75.1 comp,275 durration 110 center hyd cam,18 degs initial,38 total at 2900 rpm,750 edel carb,performer rpm intake,727,2400 stall,2.94 sure grip,ac,cruise, best of 12.9 mpg,daily driver,have towed 4600lbs, never lacked for power, ultra-bell 2 months on back order so far have 46rh to build then put the 9.25 with 3.55s back in,

That sounds like a perfect setup, almost exactly what I'm going for minus the 2.94 gears. 12.9 MPG is impressive, that's 2.9 more than I currently get with my stock 360/727 and 3.54 gears. Is your truck a 1/2 or 3/4-ton, and not sure what you mean by "short wide" I'm guessing short bed and wide....?? I have no idea lol
 
If you’re at 5000 feet above sea level or more all the time why not build it to 10.5:1 with quench and run it there?? If you have no plans on driving it below 5000 feet it’ll be fine.
 
KB hyper pistons and stealth heads would work great. Glad, you enjoyed the links, either one would work well for you.
 
sorry, my 76 with stacks is a short step side,its a d100 1/2 ton,2wd,tried 3.23s and didnt like the rpm my stall was too loose at hiway speeds, i cruise at 83mph on interstate, 3.55s and 46rh lock up would be perfect for my combination,my combination is makeing some good torque at around 2000 rpm,have to remember its a truck,its heavy,i use to have a 671 on it,was fun,i have two supercharged and a turbo car,this is just a fun truck,
 
a side note on alum heads,need to use commetic head gaskets and the thermal efficiency of the heads is like loosing 2 points of compression, just something to research,
 
Especially if you’re using aluminum heads.
As a good friend of mine calls um.....with "loonamum" heads, it'd probably be fine even at sea level. Expecially considering quench.
 
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