Here’s a thread on one I’ve got right now. 1990 318 hydraulic roller industrial engine. The cylinders are nearly as thick as in an early 360 block, but the bottom end is still garden variety eighteen. Be Careful of What You Let Get Away
As far as a premium 318 that’s supposed to be a step above the others is the early 70s -3 318. Heavy duty truck, industrial, marine application. It’s supposed to be marked with a -3 on one of the VIN pads and has a premium forged steel shotpeened & flame hardened (maybe TuffRided, too?) crankshaft. I’m a little fuzzy on this next detail at the moment so hopefully someone will chime in if I’m wrong. It’s my understanding that you would need to check if it were a reverse rotation (counterclockwise) engine such as marine applications because the oil seal surface grooves on the #5 crank crank journal have to be recut in the opposite direction for it not to leak if converted to clockwise (viewed from the front) rotation.
"forged crank" sounds nice if you are going to run boost or NOS. But I've known racers to turn the cast cranks 7200 rpms again and again. Most common "street hopped up 318's" will never outgrow the cast crank. Actually, most bracket racing 318's won't either. In fact, I know stock eliminator racers that used cast cranks.
My favorite 318 is low mileage 72-74 mound road engine. Always well built and take a hammering. Look for this decal on the valve cover. But Now remember I am old .
Wonder what that actually meant? Another mopar mystery. I'm beginning to think the entire mopar division was run while being high on acid. Hence the trippy info. Weird build codes. Fun colors. Lol. You name it. They did it.
Mound Road was the specific plant it was produced. I've owned them and found nothing different... LOL. I've never lost a 318 in fact
Both excellent points on posts #33 & 34. I personally believe that you’ll have more trouble from the stock 318 webbing and caps than you would from the crank. But I wouldn’t worry about those, either, unless spraying or adding boost. A 1973 mound road 318 with studs and stock caps will stand everything a 4 inch crank and 11:1 with edelbrock heads can throw at it. Seen one bouncing off the rev limiter at 7 grand more than a few times before.
@318willrun, The magnum heads are suppose to be a good budget cylinder head for a LA 318. My question is, with them being known for cracking would this affect the durability of the cylinder head? Does the crack get worse and cause the seats to come out or let coolant into the oil, are they worth putting money into? Same question for the 302 heads.
I had my head guy install 360 valves with hardened seats in my 920's and port them... They will flow just as good as a stock 340/360 head and have the smaller combustion chambers for the compression increase...
Of you decide to run a roller or flat tappet block and want a set of 920's, I have a set that need to be reconditioned that I could let go... What part of IL are you in??? I'm in the southwest burbs of Chicago....
I'm glad someone finally mentioned the 9.2:1 difference in a 318 thread. I'll add that the late LA rollers are likely to be a true 9.2:1 or very close vs the often "lower than spec" earlier builds where the 71-83-ish "8.8" motors are commonly tested as 8.5:1-ish. I'd imagine this also holds true for the 67-69 9.2 motors but not sure I've read about one actually measured. Also not sure how much of the comp increase is due to the head or the piston 67-69 vs 84-91. Either way, that also means if you need pistons for a 71-83 engine, a factory replacement for 67-69 or 84-91 years should have ataller installed height, giving you more squeeze. I also can't remember if 1970 is an oddball one year only ratio like the 383 HP that went from 10:1 in 69 to 9.5 in 70 and then lower for 71.
I put a early 85 (block dated 84 roller 318 cam engine) in my truck about 10 years ago still going strong. Best part it was free. Also you can run either cam.Flat or roller in those blocks.
It would be easy to get a quarter million miles out of one of those with no more than a good timing chain and gears.
many magnums out there with 300,000 and run great, most likely with cracked heads. Nobody likes the idea of putting an engine together with cracked heads including me. I think spring pressure has something to do with how the cracks behave also.
Yes. In fact, you can take any 318 head from '67 to '91 and add larger valves, and good port work and really increase flow. If you have to pay for it all, it's $$$ though. Especially today.
And outside of the factory 4bbl LA 318's, I think the torque converter and gears behind the 318 is more of a deciding factor on how well it would perform from the factory vs what year of 318 2bbl you had. For instance, 3300 lbs car with a 2120 rpm stall 904 with a 2.9 gear will fill gobs quicker than a 3300 lbs car with a tight 1700 rpm stall with a 2.45 gear. Then the "year" of that quicker 318 is noted for being "spunky". Couple that with how much smog exhaust one can add LOL.
