The "Throw Away 318"

89on35s said
For a couple years now, I have been deep into building an aluminum headed 360 for my Duster. Long story short after 5 minutes of cam break in there is a hole in the oil pan and undetermined damage in the crank case. Maybe I’ll figure it out this winter.

So, what do I do now? I can’t go all summer without my Duster! That is not an option for me. I had an old 78 318 sitting in the corner with no purpose in life. The old “Throw away 318”! I think it used to be good! Don’t really remember. It hadn’t been in a running vehicle forever! Hell let’s do it!

So, up on the engine stand she goes for a quick scrub up. I didn’t even paint it. It got a Summit K-6901 cam kit 218/228 @50, 441/441 lift on a 114 LSA. It got a Edelbrock Performer 318/360 intake because that’s what works with my AC compressor brackets. It got a Melling HV oil pump with matching distributor drive shaft and a new oil pickup and pan because I didn’t have any car stuff that wasn’t for a 360. Between what I had and what I bought I dropped about 500 bucks on the old “Throw away 318” just hoping for the best.

Well I put it together, dropped it into the car and man, I am super impressed with it for what it is! It doesn’t have great hot idling oil pressure but still has about 10lbs at 800 rpm (180* temp).

With the 4.10 rear gear and the 2.70 first gear in the A-500 it is a blast to drive around town It’s certainly better than the old wore out 360 with the wrong cam that that I had last year. I have been very nice to it so far, but It seems like it might run out of steam at RPMs over 5000. With the tiny valves that’s probably no surprise. I will drive it like it is for this year and maybe next year. Not sure on the fate of the whole 360 program now that this is so much fun and such a sweetheart to cruise. I will take it to the track and see what times it runs, and I am curious as to what kind of fuel economy it might get. It runs about 2100rpms at 65mph with the OD on. I picked up a NOS cheater plate and the parts to go with it a while back. Maybe I will try a 100 shot on this motor, Not sure yet!

I am very interested in what this engine might do with new rings and bearings, home head clean up and the ever-controversial swapping of the pistons side to side like Uncle Tony suggests. It would be a fun side by side comparison. I guess I’ll see how the motor works out in the long run. I have 800kms (500 miles) on it so far and things seem good. I did notice some oil by the breather on the drivers side valve cover, I hope there isn’t too much blow by pressuring up the crank case. I’m going to look into that tomorrow.

Cley
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You didn't mention anything about where the hole is so I will say this, I ran into a project where I installed one of those HV pumps in a small block a long time back and there were clearance issues which made a small puncture point in the pan from one of the pump cover bolts. If I recall the sump was a center sump. I can't image an engine failing that fast after working on it but anything is possible. Also you didn't say anything about hearing bad sounds and knocking as would be a case if a rob bolt failed. I can only hope you have at least part of the engine to salvage and hopefully the cam is not trashed. On a note of fast failures, I did have a 65 396 Cheby that was supposed to be a rebuilt that another guy did the engine and sent it to the shop I was in, working on the frame and drive train. He failed to find and remove the 2 bolts for the choke cover inside the runner for #5 or 7 and the engine block was scrap iron within about that amount of time. Fortunately I was able to salvage most of the engine which I used for building a replacement. I found a 454 block that had been machined, used the 396 crank and 7 rods, replaced the one that bent, bought a set of KB 427 pistons, and was able to use the bearings aside from one pair of rod bearing halves. Had to source a new set of heads since the 396 heads were closed chamber which I would never use on a pump gas late model street engine. I did a lot of other stuff to this new engine to make it a much better build than the 65 396 but since this is a MOPAR site, Just keep your fingers crossed and hopefully you still have a 360 you can fix cheaply.