1968 Dodge D200 with a 318 from who knows where

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chukardogs

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Shoreline, Washington
Hello,
I'm new to the site and obviously my 1968 D200 is not an A body but it's possible that the 318 that's under the hood used to sit in one. I'm looking for information and an opinion or two on an issue I have with the 318 in the truck.

A little about my situation. I bought this 1968 Dodge D200 with a 318, A727 automatic transmission 20+ years ago. I put a couple grand into running gear, replaced the king pins and did a basic tune up and drove it. I used it for projects and fire wood.
The truck started out as a service vehicle for Seattle City Light and has obvious signs of being altered. Based on the modifications that I can see, the truck used to be a 383, 4 speed. The cross frame under the tranny has been cut and filled with a new piece that allowed space for the automatic. The area where the clutch rod would have passed through the front wall of the cab has been covered with a plate, the master cylinder has been moved laterally and so on.
Originally I figured Seattle City Light altered this rig during the gas crunch in the 70s but under further investigation, I'm starting to question that theory.
Over the years before I bought it, the engine has had some aftermarket items installed like an aluminum Edelbrock performer manifold and an Edelbrock 650. The aluminum manifold finally cracked below the heat riser cross over passage under the carburetor. Eventually, this situation and my own stupidity caused a massive back fire that blew out the exhaust gaskets, the back of the muffler and destroyed the cam gear and thus the timing chain which brings me to my issue at hand.
While removing timing cover, I found some pitting on the timing covers mating surfaces and figured replacing the cover may be in order. During my search online, I found that all the new covers have timing marks cast into the drivers side or right side as you're facing the engine or, no timing marks at all. My existing cover has the timing marks cast into the passenger side or left side as you're facing the engine. Also, when I picked up a new harmonic balancer, I found that the new harmonic balancer is 7 inches in diameter which doesn't match the existing harmonic balancers at 5 inches. It turns out that the existing harmonic balancer is missing the outer ring and has a timing mark that is approximately 90 degrees off, counterclockwise of where the new harmonic balancer's is which may make sense considering that my timing marks on the existing timing cover are on the passenger side.
For now (to keep moving forward) my plan is to add a mark on a new harmonic balancer that matches the existing harmonic balancer and press on. (I know, I know)
My question for you all is; what am I dealing with here? Is this engine the result of almost 60 years of backyard mechanican or do I have an engine that was built this way from the factory for a specific purpose?
The truck has always ran like a champ and always had power to burn.
One other note that may be important, when I found I had to replace the intake manifold and after the massive back fire blew the exhaust gaskets out in a couple locations and the back of the muffler off, I had no choice but to do the exhaust gaskets at the same time. I found the right side exhaust manifold was warped and the surfaces were damaged and too far out of whack to machine so I had to replace that exhaust manifold. After and exhaustive search, (no pun intended) I found someone with a set that matched what I had and it sounded like they may have came off of a bus.
Anyways, if you're still reading this, thanks up front for any information or opinions on what I may be dealing with and just for what it's worth, I already understand that one man's truck is another mans junk heap.
Thanks
 
Alrighty then, I checked all the engine numbers and the casting number, 2536030 318-6 means it is an LA 318 built between 67 and 75. The 8 digit number stamped on the block below the drivers side head is PM 318R 25020444 which does not match the vehicle identification number on the tag inside and behind the drivers door. Unless this tag was changed at the time of an alteration, this may mean that the original engine was a LA 318?
If that's the case, why scarf out and replace the transmission frame support and what's with the patches on the holes in the front of the cab that align with the master cylinder brake and where a clutch rod would have protruded through the cabs forward wall?
Anywhoo, none of this changes my issue with the timing cover and the harmonic balancer.
 
"2502"0444 ... 10k day calendar says June 3, 1968.
The tag inside and behind the drivers door has the last 8 digits as 28144362. Until now, when I really need to understand what it is I am working with, I never really cared where the timing marks were. As long as I could start it and get it warmed up, I always set the timing based on best vacuum anyways. FWIW, over the years, once the timing was set, it was never where the books said it should be, which I believe was 5 before TDC. This truck has an Edelbrock manifold and an Edelbrock 650 carb with no smog pumps or components.
I'm not a gear head and honestly, I don't understand or know if those facts would make it impossible to set the timing to the books numbers. The truck always ran well and had power so I drove it.
I'd really just like to find out what it is I have under the hood. I'm starting to believe that it really is, the almost 60 years of back yard mechanican and that I may never find out what's under the hood. Thanks
 
LA 318 started in 67 and the timing mark was on the pass side thru either 69 or 70 when they switched to the driver's side. You say your outer ring is gone on damper? Then so is the timing mark. But yeah the pass side timing mark ones had a cast iron water pump.
'68 truck, 68 engine what makes you think it's not original? They didn't put vin numbers on blocks either until 69 or 70 and no, the number after "PM318..." wouldn't be the (partial) vin even if it was numbers matching, the vin would be on a machined flat spot just above the oil pan towards the back and as I remember pass side of the block.
Also how many people have had this truck since Seattle was done with it?
Aluminum manifold cracked (where you say it did). I'm quite far from having seen everything but I have never heard of that one.
 
I'm just going by what I've read. I read somewhere that the number stamped on the front, right below the head on the drivers side of the block should match the last 8 of the vehicle identification number on the tag. Who knows, that may not be accurate.
I have no idea what happened or who did what to the truck before 2003. I found it sitting on a farm in Sellick Washington. After talking to my local Automotive machine shop guy, I'm starting to understand the issue with the timing marks being on the passenger side and the outer ring missing. The fact that there is a timing bracket installed that sets the marks directly adjacent to the balancer means it was probably intended to be this way. The existing harmonic balancer has a groove cut into the outer surface in the right orientation so I'm going to put it back together as is. I had it spun on a lathe and cleaned the surface where the seal rides with 0000 steel wool so it's as smooth as it was when it was new.
The upper surface of the Edelbrock Performer manifold showed no sign of a crack but it had a sporadic vacuum leak and ran like it had a vacuum leak. Eventually (but only after destroying the cam gear when it backfired) I removed the manifold and found the heat riser passage directly below the carb had a 3 to 4 inch crack that allowed the exhaust gasses to go back into the crankcase. Very strange situation. When cold, it would start and run fairly well but as soon as it got warm or you applied much of a load it would die. I've replaced both the intake and the exhaust manifolds already. Because the resin coated cam gear was destroyed, I had no choice but to pull the oil pan to clean up all the fragments from the cam gear. Once the timing chain is finished and the oil pan is back on, I've got my fingers crossed that it'll be back on the road.
I may never know whether it's original or who did what to it. As long as it runs, no worries.
 
That was no resin.
Back then many cam gears were nylon coated to cut down on chain noise.
And if in fact the damper is missing the outer ring DON'T RUN IT. REPLACE THAT DAMPER
There are 2 places in California that offer rebuild services, with lifetime guaranteed. Damper doctor e damper dudes. I've used both.
Without the outer ring you're not damping any vibration. Basically it's no longer a "damper".
 
I was told by the local machine shop guy that I've known and trusted for years that all 318s are internally balanced and thus the harmonic balancer only acts as a unit to bolt the fan belt pulleys to. Whether this is true or not....... I have no clue. The new timing chain gear set doesn't have the nylon coating on the cam gear. It'll be interesting to see how much noisier it is.
 
woudn't run it without the balancer could end up cracking your crank just cause it hasn't yet
you need to tie together the frame rails where the old org bell housing trans mount were when they moved the rear trans mount
think they make a kit ...something about the flex in the rear spring mounts can crack the frame
 
I'm sorry, I guess I wasn't very clear before but the cross member was cut. It looks like it was cut with a torch and honestly it looks like a 10 year old could have done a better job. But, the frame was cut and a splice piece was installed.
I assumed it was done to allow for the automatic transmission to be installed but now that it looks like it was an automatic all along, I don't have a clue why the frame was cut.
 

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