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PostPosted: Thu Feb 10, 2022 9:34 pm 
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TBI Slant 6
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Joined: Sun Aug 14, 2016 5:52 pm
Posts: 160
Location: SW Washington
Car Model: 66 Valiant, 82 D150, 94 Ram 2500 TCD, 69 Dart
This tale is for my 82 D150, bought as a dead dog and needing a new engine. Details are here:

https://www.forabodiesonly.com/mopar/th ... 50.499470/

Because I sometimes learn the hard way even though I do a lot of research and try hard not to screw up, we have this thread where I finally discovered I had too much timing and was detonating, which trashed my rod bearings.

https://www.forabodiesonly.com/mopar/th ... se.507156/

As punishment for being a tuning goon, I got to pull the engine and tear it down to bare bones nothing. The crank was OK, the rods were OK, I got new rod bearings and main bearings and I'm on the way to put it back together again.

This is an ordinary driver truck. I will take it to the track for grins but it's for dump runs and so forth. I want it to be a solid runner that I can take anywhere. I put 700 miles on the fresh build before I pulled it. I was reasonably happy with how it ran. Engine details:

82 slant, freshly bored .030 over. It's a hydraulic head but I swapped out the innards for solid lifters and valve train gear.
Lean burn junk removed.
Cam is a 2106R from Oregon Cam Grinding. It is 214/210 @ .050, 444/434 lift, 108 LS on a 104 intake centerline.
Trans is an A833OD.
Gears are 3.55 but having run this thing a bit, I'm thinking I need to go with 3.91 to get the OD gear up in the power band better. It starts pulling at about 1600 and does well (by my limited experience) to about 3500 or so. I took it to 4500 a few times but that's not something that will happen often.
Tires are 29", 235/75R15 mud-and snows.
Ignition is a super six distributor with HEI conversion.
Intake is a Clifford 4-bbl with the water heat provision.
Carb is an Edelbrock AVS2 500.
Exhaust is Clifford shorties, 2-1/2" two-into-one all the way to the tailpipe through a Dynaflow Dynamax.
Head was shaved to get 7.6:1 dynamic compression.

So here's my question. If I want to change anything on the engine, now is the time. As mentioned above, I was fairly happy with how the truck ran in its original configuration. I have many options for intake, carb, and exhaust. What are recommendations for getting the most torque out of this engine? Other parts I have on hand:

Clifford adapter to run a 2-bbl on the current 4-bbl intake.
Offy 4-bbl intake.
Holley 390 4-bbl carb
Super Six intake with an almost new Carter BBD.
An old Offy 2x1 intake that was modified for 2x2, running dual Weber downdrafts.

Original cast iron exhaust manifold that was VERY nicely ported and gasket matched, the outlet was hogged out for a turbo but the heat stack was cut off so there would be no manifold heat.
Dutra Duals
Dual Dutra Duals

I'll be running this info on my two favorite sites, FABO and slantsix.org. Both have a tremendous number of slant gurus. What is your experience with any of the above parts, what would you recommend, and why?

TIA, and let the games begin!


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PostPosted: Fri Feb 11, 2022 5:08 am 
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Supercharged

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 3564
Location: Indianapolis
Car Model:
A couple of ideas:
1) I saw the porting work mentioned in the other post and that should be fine. Most intake valves can benefit from a back cut, so look into and consider that.
Over sized valves are not a requirement, but do help. In any case get the best multi angle valve seat work that you can afford. Get that work done by a hot rod machinest.
2) Advance the cam a bit more to 102 ICL. Buy one of those 16 inch diameter degree wheels and really nail it.
3) consider adding a full time vacuum gauge and AF gauge to the cab. Those two are really helpful for long time tuning and keeping track of how the engine is running.
4) My 83 D150 had 3:23 rear gears, I swapped to 3:73 and it really helped. Use an online gear selection tool to see what rpm’s you will be running at your high way speeds to help with the decision making.
5) If not recently replaced take a look at the clutch and TOB, it will never be easier than now.

Question, does your truck have an oil pressure gauge that has a readable scale? Using mechanical lifters with a hydraulic head can divert a lot of oil to the top of the cylinder head. That will cause a drop in oil pressure to the mains and rods. If you do not have one, add a mechanical oil pressure gauge and see what the oil pressure really is. If your cam was a mechanical lifter cam, you may not have that issue, but if the cam was a hydraulic cam with the full groove on the rear cam journal, it is sending a lot of oil up top. Some folks add a restrictor to the oil passage in the hydraulic head to restrict the oil flow up top.

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PostPosted: Fri Feb 11, 2022 6:23 am 
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Joined: Mon Oct 21, 2002 11:08 am
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Location: Blacksburg, VA
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I agree with everything DadTruck said.

For truck torque and no high RPM, you definitely want either the Offy intake or stock supersix intake. If it were me, I'd use the Offy 4V since you can use any of those 3 carbs w/o switching intakes. Try the BBD with a transdapt/mrgasket parts store adapter plate, and I bet you will be very happy with that. Eddy and then holley would be my 2nd and 3rd choices.

Happy building!

Lou

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PostPosted: Fri Feb 11, 2022 3:24 pm 
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Joined: Wed Nov 06, 2002 1:57 pm
Posts: 2096
Location: Everett, WA
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I wouldn't change anything. Just reassemble the engine and pay particular attention to cleanliness and sufficient assemble lube. To me, a bad bearing in 700 miles indicates one of 3 things. Bad bearing, dirt in engine and/or insufficient lubrication on initial startup.


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PostPosted: Fri Feb 11, 2022 5:59 pm 
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Joined: Wed Oct 23, 2002 7:57 pm
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Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
I would go to the Offy intake and probably keep the AVS carb. But I would definitely swap to 3.73-4.10 gears if you can afford the swap. That will make everything feel much better all the way around. I have run 3.91's with OD and you can easily still cruise on the highway.

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PostPosted: Sat Feb 12, 2022 7:11 am 
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TBI Slant 6
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Joined: Sun Aug 14, 2016 5:52 pm
Posts: 160
Location: SW Washington
Car Model: 66 Valiant, 82 D150, 94 Ram 2500 TCD, 69 Dart
DadTruck:
Over sized valves were done with the head work, I forgot to put that in the initial info. They are about 1.68/1.44 IIRC. I have a vacuum gauge and access to an A/F gauge for tuning and will be using them. Both clutch and TOB were replaced with the first rebuild. Good point on oil pressure and which cam got reground - it was a solid cam from the Volare parts donor. I intend to put a full set of gauges in the truck.

To all:
Good points, and thank you. I am certain I will have to revisit the current 3.55 gears. The truck was fine for putzing around town, but when I hooked the trailer to it I had to slip the clutch a LOT to get it going. Also, cruising in OD at 65-70 MPH was about 1800 RPM. I'd like it to be more like 2300-2400 on the freeway. I have the parts to do a T-5 swap and am giving that serious consideration. I've been playing with a gear/RPM/speed calculator. The T-5 with 3.91 gears makes first gear ridiculously low, but that would likely be a benefit as it would serve as a granny gear. Second would be my normal unloaded start-off gear, and I still get OD on the highway in a decent spot on the power band. Opinions on this thought process are warmly welcomed! :mrgreen:

I'm not sure why I initially chose the Clifford intake but I do recall now it is considered more of a high RPM intake, and the Offy more for a street driver. I can easily swap out to the Offy.

Next question, would I be better served with the Clifford shorty headers or going to Dutra Duals?


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PostPosted: Sat Feb 12, 2022 9:04 am 
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Joined: Mon Oct 21, 2002 11:08 am
Posts: 15362
Location: Blacksburg, VA
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3.91 with 29" tires will be totally fine.

Dutra Duals more durable and easy to seal and build exhaust system. Shorties will make more top end, but I doubt you would see a lick of difference below 4000-4500. If shorties, then make sure to run secondary pipes from collectors to a Y-junction about a foot behind the trans X-member for good low end power. If using shorties, get the dead soft aluminum gaskets and double nut the collector bolts. Everything else will leak over time. Best to use the thick green gasket from Brian Droschak or Remflex gasket with shorties. Dutras will work work about any int/exh gasket. I would use 2X2" pipes off the dutras or headers into 2.5" single out the back. This will breathe well but not be oversized (condensation and more noise).

Lou

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PostPosted: Mon Apr 25, 2022 10:14 am 
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Joined: Fri Feb 29, 2008 10:49 pm
Posts: 1543
Location: Salem, Oregon
Car Model: 1984 D100 Shorty Custom
Whichever 4 barrel manifold you have left over, I'll gladly buy; need one for my 84 D100!

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