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| Cam Recommendations for 1984 Truck Build https://slantsix.org/forum/viewtopic.php?t=67289 |
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| Author: | scraigallen [ Fri Jun 09, 2023 9:48 am ] |
| Post subject: | Cam Recommendations for 1984 Truck Build |
I am thinking about upgrading the cam in my slant six build and was hoping to get your input on the best one for my build as follows: 1984 Dodge D100 Truck Build - Going for reliability, smooth running, good torque (250 ft-lbs), decent horse power (180 ft-lbs). Trans is A833 4 Speed Motor = 1986 Slant Six 225 with a previous rebuild .040 pistons. Not sure if block has been shaves 0.10 - will measure soon. Head = Stock 1986 Head with plans for minor port matching and cleaning up. Not planning to upsize valves. Will upsize springs with cam kit. Intake = Aussie speed mid length with Weber 38/38 Carb. Exhaust = Dutra Duals or similar. Ignition = HEI Mod I would like the motor to have performance similar to a stock Jeep 4.0 with good pulling power with the 4 speed. I am not looking for a drag racing motor. In my past builds, I have not upgraded the cam, so this is new territory for me. From the posts I have read on the site, I was thinking a mild RV cam but was hoping that you that have more knowledge than me can help me find the right cam for my application. Thanks! |
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| Author: | Rick Covalt [ Fri Jun 09, 2023 2:40 pm ] |
| Post subject: | Re: Cam Recommendations for 1984 Truck Build |
What rear gears are in the truck? Even with stock valves I would clean up the bowl under the seats. And you may want to plane the head some more to bump the compression a bit more. That will help with power and gas mileage. Of course check the measurements for sure. |
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| Author: | SlantSixDan [ Fri Jun 09, 2023 5:11 pm ] |
| Post subject: | Re: Cam Recommendations for 1984 Truck Build |
The stock '81-up hydraulic-lifter cam is a wimpy thing. Most of the aftermarket cams, by whatever description ("High Energy", "RV", "Torquer", etc) are ancient generic (often Chevrolet) grinds applied to a Slant-6 cam blank. There are a lot fewer options in cams for the hydraulic-lifter setup. You might want to give some thought to converting to the pre-'81 solid-lifter arrangement instead. You'd have to do a valve adjustment from time to time, but you'd have a lot more and better cam options readily available. If you were to do that, the Dutra RV-15RDP from Oregon Cam would go well with your intake setup. The RV-10RDP would be a little milder—smoother idle, etc—but still a nice improvement over the stock '71-'80 solid-lifter cam, and an even bigger improvement over the '81-up hydro cam. |
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| Author: | Jase [ Sun Jun 11, 2023 6:49 am ] |
| Post subject: | Re: Cam Recommendations for 1984 Truck Build |
Does anyone regrind cams for the .904 lifter size? Did the Direct Connection/Mopar aftermarket cams utilize the advantages of the "faster" ramps that the .904 lifter would tolerate? |
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| Author: | DadTruck [ Sun Jun 11, 2023 7:46 am ] |
| Post subject: | Re: Cam Recommendations for 1984 Truck Build |
Hughes Engines says they have mopar cam lobe profiles that are designed to work with the .904 diameter lifter https://hughesengines.com/ see their Tech article section On the topic of picking a cam for low rpm torque, that is the route that I took for the slant in the 83 D150. the article linked is from that project https://www.slantsix.org/forum/viewtopi ... 19&t=43301 and while we are talking cams, a few of my recommendations. 1) spend the $75.00 and get a copy of Dyno Sim / Desktop dyno You can run simulations with different cam profiles, lifts, advance - retard settings and see what those changes do for torque and HP curves. The better your inputs are for: compression, carb CFM, head flow, ignition timing the closer your Dyno Sim output will match reality. I had the 83 D150 on a chassis dyno years ago and the torque- HP curves were right on line with what Dyno Sim had predicted. http://www.proracingsim.com/dynosim6.htm available through Summitt and other retailers 2) in a truck application, I would stay with hydraulic lifters. The valve cover and the rocker arms are a lot further away in a D series that thay are in an A body. 3) I would not count out a 'stock' 81 and up hydraulic cam if low RPM torque is the only goal. Do a Dyno Sim simulation with the stock cam and you will see a lot of torque way down the RPM chart. Ultimate HP is limited as the engine just runs out of air above 3000 RPM, but its worth a look if low RPM Torque is the only goal. And here is an article with good basic camshaft information. https://www.motortrend.com/how-to/under ... afts-work/ Regards DT |
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| Author: | Dart270 [ Sun Jun 11, 2023 8:38 am ] |
| Post subject: | Re: Cam Recommendations for 1984 Truck Build |
Lots of good ideas/experience/opinions here. The first thing I would do is decide on the static compression ratio you want, and build the engine for that, then decide on the cam. For pump 87 octane, I would go for 8.5 - 8.8:1 static CR. For 91-93 octane premium gas, I would go for 9.3 - 9.6:1. For your application, I would suggest staying with a hydraulic cam and we can design a custom cam from Oregon that will use hydraulic lobe profiles. Lou |
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