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318 Stroker Motor

skymynx

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I've been going all over the place with what to do with my 318 motor. I've debated adding nitrous to it, building a supercharged motor and have now started to look into building a stroker motor. Trying to still do my research so that come tax return time when I have the money I'll know what I want to do.

A little about the car. Its a 1972 Dodge Charger with a 318/904 combo. Right now the motor just has a Weiand Action+ intake manifold with a Holley 670 on top. Other then that the motor is stock. I will be replacing the rear end later this year with a 8 3/4 rear with 3.73 gears. My goal with the 318 is to get it between 400-450 horsepower. Will be replacing the factory exhaust this spring with hooker competition headers and 3" dual exhaust.

I've never built a stroker motor before so its still a very unknown area of knowledge for me. What I'm looking for is people's experience with a stroker mopar sb. I'm very concerned about it being very streetable as its my girlfriends car. I want to build a street friendly mild car. Please feel free to give any advice you have in regards to this subject.
 
Well, with the 4 inch arm in there and @ .030 overbore, you'll be @ 390 cubes. And that's preety cool to me. At that CID, a bowl ported 340/360 head, cleaned up and port matched (Is a fav of mine) or cleaned up Edelbrock heads should be a very good choice for the project.

Intake wise, a RPM or Stealth or even a older LD340 would be what your looing at for a driver. You may want to go up in cfm though. The unit you have now will be fine for the street, but, lacking on the top end. It'll be fine for use though. Break in and drive around.

IMO, I'd look to the Hooker Super Comp headers @ 1-3/4 tube size. They have great! ground clearance. A larger tube for breathing.

Cam wise, a cam with a 230* duration @ .050 will do it for 400 HP. The big engine will swallow up the duration and it will seem like a smaller cam in the big mill. The above combo minus the big stroke makes about 400 HP on a 340/360 easy, for sure if you can tune a 750 on top of them well.

Your piston selection will have to have some thought in it. Try not to go above a 10-1 ratio. Even at 9-1, you'll still make some very good power. Add another point for aluminum heads.

This above should create a very nice daily driver that is easy on octane requirements, good to drive without being snooty.

Heres a example of a cam that could do you well. It's a split duration from Comp.
http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=628&sb=2
and a ever so slightly more aggressive cam with more lift. Good with Edelbrock heads.
http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=631&sb=2
 
Thanks for the info. I'll look into the hooker super comp headers. I might as well go big or go home right. I'll prolly give comp cams a call when the time comes for picking out the cam. It would suck to have to get a new intake manifold as this one has less then 5 miles on it currently. It is about a year old, but the car wasn't driveable last year, nor did I have the time or money (in the process of buying a home) to make it driveable.

No little confused about the amount of power that your saying to expect. Your saying I should expect somewhere around 400. I remember reading mopar muscle magazine article where they rebuilt a 318 with magnum heads and they got a little over 400 if memory serves. I was hoping to be closer to 450 on motor. I plan to run a conservative 125 shot ontop of the motor work.
 
Just slapping the parts together like Rumble suggested I think will give you great results, but in order to maximize your HP potential lots of careful tuning will be required. Also, with a 4" arm you will have higher piston speed and stresses will be higher - so don't rev the snot out of it. I'm sure the kit you will use has quality forged pistons and maybe H beam rods.

I saw a 318 powered 68 fastback at the drags and it was running 12.40's with 4.30 gears. No stroker, just a 318 built with 340 heads and a MoPar .528" cam. It's just a 340 with a slightly smaller bore is all. Hopefully that gives you more encouragement!
 
That does give me some enouragement. We will have to wait and see what ends up happening. Thanks for the info though, I will continue to do my research and will most likely post my findings along the way before I purchase. Want to the motor to be in sync with every little part.
 
318 strokers can be ground pounding, pavement stomping BEAST! I love the idea too. There is a TON of info and a few resident experts (I mean Guru's) on the subject at For A Bodies Only. Keep in mind, if the Mopar small block was a chevy or ford it wouldn't be called a small block. Also check out "How to Build Big Inch Mopar Small Blocks". It's a great book with a ton of info that will get you asking the right questions and better understanding the answers. That $20 and a little toilet reading could save you a lot of money.
 
318 strokers can be ground pounding, pavement stomping BEAST! I love the idea too. There is a TON of info and a few resident experts (I mean Guru's) on the subject at For A Bodies Only. Keep in mind, if the Mopar small block was a chevy or ford it wouldn't be called a small block. Also check out "How to Build Big Inch Mopar Small Blocks". It's a great book with a ton of info that will get you asking the right questions and better understanding the answers. That $20 and a little toilet reading could save you a lot of money.


And the cool part is you can usually get a 318 for hauling it away!
 
Thanks. I ordered that book this morning. I'm sure it will answer alot of questions.
 
poly?

Will that crank fit a 66 318 poly?
 
poly

Never mind I forgot I am unemployed.No money.Plenty of time to dream.I had some 318's in A and E bodies back in the 80's,cam- headers- 4 barrells and set of 3.91's they were alot of fun.
 
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