Posted by Dave Horvath [73.154.113.3] on Thursday, November 12, 2015 at 20:39:55 :
Jeremy picked up this 318 poly out of a buddy's 1966 W500. Ordinarily, the W500 would have had the 318-3. This block is stamped 318-2. The 318-2 is described as the semi-premium engine and has roller timing chain and hydraulic lifters. It takes the regular size 14mm JY-10 Champion spark plugs.
The 318-3 is described as the premium engine and adds lower compression ratios, special alloy rods and bearings, higher pressure oil pump, larger oil pan, tighter tolerances for the crank and pistons, and slightly smaller valves with sodium-filled stems. It takes the larger 17mm F-10 or FX-10 spark plugs.
Even though the block is stamped 318-2, this engine has the 318-3 heads with the larger spark plugs. I expect when we open it up we will find it has the smaller valves. Can't wait to see if it has the rest of the premium components. My guess is Dodge built it as a premium engine with whatever block they had on hand. We'll see.
Plans are to build it up and put it in the swivel frame with an NP435. We are thinking we will go with the 462/.460 cam grind from Gary Pavlovich for better street performance. Don't want an RV cam grind because I'm already concerned about breaking axles. The swivel mechanism doesn't allow room to run a centered driveshaft off the transfer case for a centered rear differential. Don't need to increase low end torque with the offset differential. Make sense?
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