Mopar question

[offroadrolls]

I just bought the first Mopar in my life. Worked on plenty of them over the years but, never owned one. Anyway what I got is a 1970 W 500 2 ton truck with a 318 in it. The ID tag calls it a 318-3. I've done some research and understand that the -2 or -3 in my case is supposed to indicate a higher level of internal engine quality vs. a stock 318 in say a Dart or something. Any Mopar experts on the forum that can confirm this? And if so, any details as to what's better?

[smallfoot]

From what I've read, I'm no expert but lots of info, the crank is forged and hardened, the blocks are left heavy and the flow on the heads was improved. The motor is a keeper!

[Dr Crankenstein]

I don't know Mopar stuff, but medium duty GM trucks of the era had "industrial" engines with forged cranks, heavy 4-ring pistons, specific (low flow) heads, intake manifolds and cooling arrangements... all designed for low RPM/high torque applications and virtually useless in a performance build.

I'd expect your 318 to be similar, given the application... I-R-POPS? MercuryMac?

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[phil cottingham]

I thought that in the 60"s and early 70's there were 2 different 318 engines. The ones used in the bigger trucks were a different engine from light truck and car 318's. No interchanging parts. I could be wrong. It's been a few years.

[MercuryMac]

I can't answer about the -2 or -3, but I think I had one in a D-600 three ton. It pulled well, even when loaded and it'll be tougher than nails. I, especially liked the New Process five speed trans in the truck. Anyhow, Dodge didn't make a dud motor, ever, so keep it and drive it.

Phil, in the mid sixties, the Polispheric, [ poli for short] 318 was phased out and the LA 318 was brought in. 1967 was the last year for Poli's in pick-ups, and I think 1962 might have been the last year for wide block Poli's in cars as the LA 273 was introduced in '63. I'm guessing at some of this but it explains the stories that you heard about the two different 318's. The two motors look quite different. I'll see if I can find some pictures. Yes, the first one is a Polispheric compression chambered 318 out of a 1966 Dodge pick-up. The second pic is an LA 360 that looks just like an LA 318.

[Blue Eyed Devil]

Originally Posted by MercuryMac

1967 was the last year for Poli's in pick-ups, and I think 1962 might have been the last year for wide block Poli's in cars as the LA 273 was introduced in '63. I'm guessing at some of this but it explains the stories that you heard about the two different 318's.

The 318 Poly A series was used in trucks and passenger cars until 1966. The early '56-61 design has a different bell housing pattern than the later '62-66 version, which used the LA series pattern.

[phil cottingham]

Originally Posted by MercuryMac

I can't answer about the -2 or -3, but I think I had one in a D-600 three ton. It pulled well, even when loaded and it'll be tougher than nails. I, especially liked the New Process five speed trans in the truck. Anyhow, Dodge didn't make a dud motor, ever, so keep it and drive it.

Phil, in the mid sixties, the Polispheric, [ poli for short] 318 was phased out and the LA 318 was brought in. 1967 was the last year for Poli's in pick-ups, and I think 1962 might have been the last year for wide block Poli's in cars as the LA 273 was introduced in '63. I'm guessing at some of this but it explains the stories that you heard about the two different 318's. The two motors look quite different. I'll see if I can find some pictures. Yes, the first one is a Polispheric compression chambered 318 out of a 1966 Dodge pick-up. The second pic is an LA 360 that looks just like an LA 318.

Maybe my memory is better that I thought or maybe I got lucky. I worked on a few back in the early 70's but not touched one since. Mostly in older log trucks.

[Blue Eyed Devil]

Originally Posted by phil cottingham

Maybe my memory is better that I thought or maybe I got lucky. I worked on a few back in the early 70's but not touched one since. Mostly in older log trucks.

Actually there are several interchanging parts. The blocks are nearly identical - So much so that LA heads can be bolted onto a A block, and A heads can be used on an LA block with some minor machining. They are meaty as well, with the ability to be bored .105 over relatively easy. That can take the 318 all the way to 426ci! Distributors are the same as well.

[offroadrolls]

Thanks for the info guys. Here's a picture of the Truck that has the 318-3 in it. It was brush fire truck in Nevada. It has just 13,000 miles on it. I bought it from a guy about an hour north west of Laramie WY. We drove it 175 miles home getting 6.5 miles to the gallon. Originally I thought I'd be putting a 6BT Cummings in it but after driving it it's just too tight to mess with. Plus with 6.81:1 axles in it, the 318 was turning about 4200 rpm at 65 miles and hour. So I'd say it's geared a little low for a Cummins.



Here's a couple pictures of the engine. The most notable difference is the timing chain cover. It's a different casting than what's used in cars and pick ups. It allows for the water pump to be mounted higher so the fan is centered to the humongous radiator. Also, there's a hard line plumbed from the water pump to the carb base.




I put a wrench on the crank and the slop in the timing chain was minimal at just 4 degrees. So I'd say the 13,000 miles is probably true. I've got a Chrysler electronic ignition coming for it, along with a carb kit and a fuel pump. I'll start a build thread soon as there's big plans for this gem!

[Old Iron]

So it's four wheel drive too???