Should I bore a 74 318 to 340 ci or just go with a 360?

318 or 360

  • 318

    Votes: 61 27.1%

  • 360

    Votes: 164 72.9%
  • Total voters
    225
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racerdude5

racerdude5

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I have a 74 Duster with a 318 and I think it would be kind of neat to keep the matching numbers engine but if it's for my best interest it can go. So I would like to know if it would be a good idea to just bore out my 318 to 340 or would it be better to get a 360 instead. Would I be better off getting an LA 360 or a Magnum 360? If I could do what I honestly would like to do, I would get the Mopar Performance A8 (because of the aluminum block) and have it sized to 340 or bigger maybe, but that's out of my budget right now. I'm not planning on keeping anything stock on my engine, I want to get aluminum heads, a new cam, and more. I like the sound of the Edelbrock Victor heads which I would match with a Super Victor intake, but is there a better choice, should I just go with regular LA Aluminum heads and port them? My plan is to be able to use my Duster as a weekend drift car so I need to be able to hit pretty high RPMs, but also need to be able to use it as a somewhat reasonable daily driver. My main priorities are Performance/Economy, Reliability, and light weight.
 
yes,,bore it out to a 340..

but first fine out what the bore is on a 318...then the bore on a 340...and do the math...
 
economy and a set of yet to be released, high flow victor heads......kind of seems like an oxymoron....
 
If I had the cash, I would've done the 396 stroker. That's a 318 bored .060 over and a 4 in crank. Then you can say you have a 396 in your car. Payback to Chevy for saying they have a 383 stroker. LOL.
 
3.91 to 4.040 ? I don't know of many blocks that you can bore .120 and have much cylinder wall thickness left! Have your block bores sonic tested to see what a "safe" overbore is possible.
 
................Alrighty...........i speak from experiance about boring 318s out to 340 size.........yes it can and has been done............u need to get the block sonic tested to check the thickness......i dont believe a 74 block will go that far........i've had 68-9s done...........anything over a .060 overbore will be custom[expensive]pistons...u will be way farther ahead to build a 360, theres all kinds of stuff out there for a 360 build.......kim........
 
kimmer is right. It can be done. A sonic check is a must. If it was me though, what I would do would be build a 390. I mean, boring one that far AINT gonna be cheap. You could probably buy a stroker crank for that money.
 
Ok i'm building a 318 so i'm bias to the little underdog but what gets me is the fact no one has said a word adout this guy using his duster as a DRIFT CAR!!!!! Lol that is great when you get it done there better be some videos posted racerdude5
 
Go with a built 360, but if you want to cruise the car build the 318, hi compression, either way I'd go stock stroke. But if you opt to stroke go for the 360/408
 
I don't think you can bore a 318 to 340! the walls would be super thin and would over heat. You Could Bore a Polly 318 to a 340 cause thay have thicker walls. but you can never go wrong with a 360.
 
valentino automotive said:
I don't think you can bore a 318 to 340! the walls would be super thin and would over heat. You Could Bore a Polly 318 to a 340 cause thay have thicker walls. but you can never go wrong with a 360.
Click to expand...

Some of them will go that far. You have to have them sonic checked first.
 
I had that Question years ago when I was a teen! The Machinist looked at me all crazy when I asked that Question I wanted a 340 but it was not going to happen. I know thay have a company that does it but thay pick ther blocks very careful so not all make it to be a 390.:blackeye:
 
Performance, economy and reliability? :-k

Seriously though, what you need to do is decide what your budget actually is, and how much horsepower you want to make.

318's can be made to run at 400 hp with fairly modest builds, and a set of aluminum heads would put you well on your way. But even an aluminum headed 318 build will probably set you back over $5k, since the heads will end up costing close to $2k when all is said and done.

If you want more than 400 hp, get a 360. The 360 will probably be cheaper to build if you have a specific power goal, anything over about 300 hp will mean the 318 will have to be a more radical build to get to the same level, ie, the 360 can have a smaller cam and still make more horsepower. The 360 will make more torque too, although it won't rev quite as well.

And if you're building a drift car, don't forget that you'll probably need to spend $1k MINIMUM upgrading your suspension just to get things to entry level- bigger torsion bars, bigger brakes, sway bars, frame connectors, not to mention all new bushings, ball joints, etc. Its not a small undertaking...
 
Thanks everybody for replying. So according to DusterPaul I should stroke it instead of boring it, would it be a good way to go to stroke it to 340? Should I bore and stroke it?
 
Look, get a 360 crank with 318 mains. Do a cleanup bore on your block (.020-.030") amd new pistons to match the new stroke. You should be able to get a kit fairly cheap. You'll now be 344 ci and have your numbers matching block. Throw on some decent heads and go hunt some chebbys!
 
I say if you want to keep the teen,stroke dont bore.No future rebuild with a max bore.
 
Dude....here's the best thing. If you're on a budget, build the 318. You already HAVE it.
 
Gonna have aLOT of over heating problems with such a large overbore,and you wont make as much power either. You need the bore to stay round and true,and with that much meat cut out of it,it wont.

Go for the 360.Or just put a stroker kit in the 318
 
Well, i gather that your not a experienced drifter so i think you should build a 360 and see how it goes. Probably would be the least cost to try and break in to that sport.......jmo
 
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