318 HEAD QUESTION

[koshe]

I am in the process of building a 318. Motor is not decked. Cylinders bored .040. I am putting 360 heads on it. Some say the 360 heads need to be shaved .050.  (I am running a Lunati cam with 480 lift) The block is a 68 and the heads are 75-76 era. These should have hardened valve guides right? Do I loose compression if I do not shave these down? What should I do?

[chargd72]

You will absolutely loose compression going with 360 heads.  Milling will be necessary but I'm not sure how much.  Also, that's a lot of lift for a 318.  What are your plans for this build?

[elacruze]

There are a lot of good articles on building a 318 on the web, do some searching particularly in the Magazines.

Generally speaking, 360 heads (unless they are the pretty rare small-port 360 heads) are not a great choice for a 318. You'll give up a lot of low-RPM port velocity, making the motor lazy until it revs up. Particularly with stock-height pistons, you'll have pretty low compression, and any cam at all will give you a fat lazy pig that's no fun to drive.

Hughes Engines sells 318 pistons with a higher compression height which will zero-deck your block for about $300. If you want real compression you'll have to spend more on some dome pistons.

Here's my recipe for a 318-keep in mind that I'm building it on the cheap and it's going in a pickup so I'm not looking for high-RPM power, just a surprising motor that runs like stock.
http://www.dodgecharger.com/forum/index.php/topic,69895.0.html

[koshe]

My cam specs are:
•Advertised Duration (Int/Exh): 292/292
•Duration @ .050 (Int/Exh): 230/230
•Gross Valve Lift (Int/Exh): .480/.480
•LSA/ICL: 109/105
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 2000-5500
•Includes: Cam Kit

This car is going to be driven hard. This cam will help with the low end issue along with a dual plane intake.

[elacruze]

I would suggest that your cam would work better overall with stock 318 heads than with the 360 heads. The big ports may be faster at >4000RPM but you'll lose a lot of drivability.

We've had lots of discussions about 318 builds, and even I have to admit that buying a running 360, milling the heads and camming it is cheaper, easier, and will make more power and torque than a 318 for half the money.

I just don't always roll with my own advice.

[chargd72]

Like elacruze said, you won't be able to use all that runner mass until the engine is really winding.  But if you're like me, and want to make parts work that you already have.  Give them a shot.  But I have a feeling you're not going to be satified with your take-offs from any stop light. 

Everything I relay to you is from what I've collected thru reading others testimonies.  I am on my first engine build and trying to make a respectable 318. 

Here is the route I'm going.

Stock crank
Federal Mogul sealed power pistons
340 repro cam with .464/.464 lift
Air gap manifold
1 inch hvh tapered spacer
have a 750 eddy carb that I'll give a test but probably trade it for a 600-650
cast 302 heads with 1.88/1.60 valves and pocket port job/matched int/exh runners & 340 damper springs
headman headers 1 5/8