318 ideas..opinions please.

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cross_thread72

cross_thread72

Tattooed white trash
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A friend donated a 318 to my cause, it's disassembled and off to the machine shop. My plans are a healthy overbore, it's already .040 and had a ridge, so it's going to have to go .060 the machinist is going to do the oil system mods, line hone it, and torque plate hone as well. The crank is steel according to the machinist and will clean up .010. I've ordered a set of kb399 pistons which have the highest compression height of any 318 slug available. Everything will be balanced and I'm running the eagle I beam rods. I'm trying to beat the same friend out of a set of magnum heads he has, they've had the guides cut down for retainer clearance, and have had really light cleanup done on the ports, and he also has a set of Harland sharp full roller rockers. I'm leaning towards a Howards hydro roller p.n. 713175-10 topped off by an rpm air gap intake. This is my first mopar build, and everybody I know says I'm building it like a chebbie and none of this will work. Thoughts, comments, opinions, smart remarks?
 
Certainly won't be a pump gas motor.
 
Sonic test the cylinder walls to be sure it will take a .060 overbore first before you order the pistons.
 
If You trust your Machine shop then who cares what the Nay Sayers think? I'm no expert on Custom builds but it sounds freakin COOOOOL. As long as nobody on here gives you concrete reasons not to, I say Do it. I have seen the 318/360 debate 1000 times. Mostly, The free Factor put's the 318 ahead but yes you can get more out of the 360. But you already have the 318 :glasses7:
 
73AbodEE said:
with all that work , i would start with a 360
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I wasn't given a free 360 core, and IMO there's noting quite like a high winding small block, sometimes less is more. I'm not worried about it being a pump gas motor, it might see the street, but I doubt it, it's only going to be driven 1/8 mile at a time.
 
If you don't mind race gas, it'll kick ***. Go for it.
 
cross_thread72 said:
I wasn't given a free 360 core, and IMO there's noting quite like a high winding small block, sometimes less is more. I'm not worried about it being a pump gas motor, it might see the street, but I doubt it, it's only going to be driven 1/8 mile at a time.
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im all for the 318, i was just thinking cubes, but hey, free is free , i have one myself that i would love to get a shitpot of horses out of
 
Like the cam (might even go a bit bigger) much like what I'm gathering parts for. My pistons are forged with -4.9cc dome. Have you calculated the compression ratio? Love the high rpm 318 idea, that's the way I'm going. Have good quality main studs installed when line honed. Really don't understand that chevy comment, unless they're confused about Magnum rocker studs. I like it.
 
If you were building it like a chevy it would blow up! -smart remark


Build sounds good for a limited street use engine. Go for it and let us know what it does in the 1/8th!
 
Coronet 500 said:
Like the cam (might even go a bit bigger) much like what I'm gathering parts for. My pistons are forged with -4.9cc dome. Have you calculated the compression ratio? Love the high rpm 318 idea, that's the way I'm going. Have good quality main studs installed when line honed. Really don't understand that chevy comment, unless they're confused about Magnum rocker studs. I like it.
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With a large bore, thick head gasket it should be around 10.5:1, and yes it's studded with arp studs. I guess the comments stem from the love hate relationship between Chevy and mopar guys. On paper it looks like a screamer, I might open up the heads a little bit so it's not wheezy on the top end, my target is for it not to be under 6k rpm except when I'm pulling into a parking spot.
 
cross_thread72 said:
I wasn't given a free 360 core...
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And it sounds like you weren't given free machine work, hardware, pistons, cam, etc either. You're sinking a significant amount of money into your motor. In the scheme of things, the cost of a core short block doesn't seem too much. But you're call.

A used std bore 360 magnum block would be like $200-300 tops and offset some of the retrofit roller cam costs. Non magnum 360, probably a little less.

...and IMO there's noting quite like a high winding small block, sometimes less is more. I'm not worried about it being a pump gas motor, it might see the street, but I doubt it, it's only going to be driven 1/8 mile at a time
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That hydraulic cam is only listed at 1,600-5,600 operating range. If you want a high winding small block get a bigger solid cam that revs it to 6400-6800 rpm.
 
Wow, cuda, I need to come pick up cores wherever you're at. You can't touch a 360 here for under $400 give or take on the magnums. So far the only thing that has cost me are the pistons/cam. I traded a rifle for the machine work, so if I can get the heads and rockers from my buddy fairly cheap I'll have right around $1k in everything. As far as the cam goes I think I'll be right on target 4* advanced with the 1.6 rockers, I've twisted hydraulic rollers to 7k in non Chrysler engines, is there something I'm missing?
 
cross_thread72 said:
Wow, cuda, I need to come pick up cores wherever you're at. You can't touch a 360 here for under $400 give or take on the magnums. So far the only thing that has cost me are the pistons/cam. I traded a rifle for the machine work, so if I can get the heads and rockers from my buddy fairly cheap I'll have right around $1k in everything. As far as the cam goes I think I'll be right on target 4* advanced with the 1.6 rockers, I've twisted hydraulic rollers to 7k in non Chrysler engines, is there something I'm missing?
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Check out Craigslist, they're on all the time. I don't dig the 360 but that's just me.

It does crack me up when people say "It's small but a high winding smallblock"....I'll take whatever makes the most power at the lowest RPMs. Try a single turbo, it'll be cheaper, make more power and be more reliable than a 318 turning crazy RPMs, and still run on pump gas.

If you're taking hydraulic cams to 7k RPMs on a regular basis, fast n furious style (1/8th mile at a time :D) then you're likely going to have issues, that's why they're telling you to go solid.
 
Hmmm....That's good food for thought, I've got a lot to learn about chrysler engines, I guess you can't build and twist them like a chebbie.
 
You might want to spin it more than 6K, IMO, that cam isn't going to do it without some serious head work. Too short on duration. My guess, it will be all done in a 318-330 inch engine at 6Kish range.

Yes, stock chrysler hyd rollers will go 7K with good valvetrain components.

Sounds like an interesting build.
 
The thing with Chevy is....they work GREAT, no outlandish parts needed, parts are everywhere and they are cheap. Especially the LS series is great, even more especially with a turbo :p

Plenty of guys do high RPM stuff, that's where the power is at when you're NA, especially with a smaller engine. I'm definitely not saying it can't be done :)
 
Aren't KB399 domes I don't think they will play nice with your closed chamber magnum heads.
 
They are domes, I plan on hand fitting them to the combustion chamber and they'll have to have some shallow valve reliefs cut. Once again I'm basing this build off some of my chebbie engines. I'm not sure why I keep hearing things like "you can't run more than 9:1 compression on a mopar" "you can't run domed pistons with closed chamber heads" I've ran 10.5:1 big block chebbies on pump gas, with domed pistons on canted valve closed chamber heads. I'm I still missing something? I plan on running race fuel, I have the option of alcohol, I have a carb and pump to go that route. I don't care about street manners, I just want to go fast.
 
cross_thread72 said:
They are domes, I plan on hand fitting them to the combustion chamber and they'll have to have some shallow valve reliefs cut. Once again I'm basing this build off some of my chebbie engines. I'm not sure why I keep hearing things like "you can't run more than 9:1 compression on a mopar" "you can't run domed pistons with closed chamber heads" I've ran 10.5:1 big block chebbies on pump gas, with domed pistons on canted valve closed chamber heads. I'm I still missing something? I plan on running race fuel, I have the option of alcohol, I have a carb and pump to go that route. I don't care about street manners, I just want to go fast.
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If youre not in it for street manners, then super/turbo charge that bastard and go for broke :twisted: There is nothing like the sound of a blower or a the beautiful sound of twin turbos spooling up!
 
I don't see why you can't run what ever CR you want if your using racing gas and make sense that the domes and closed chambers will work if your custom fitting them. A 318 is just a smaller bore 340 it can make same Hp just a little higher in rpm, there's a guy on here that has custom forged piston and 2.96 crank for sale to make a 318 in 288 if you really want to spin it 10000+ rpms.
 
If you're gonna run race gas anyway, anything under 13.5 would be dumb. What I mean is, if you're gonna do it, DO IT. lol
 
No reason you cant build a 318, Chevy uys build 327s, ford guys build 289s and 302s.
 
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