302 heads vs stock 67 heads on a 318?

[Secret Chimp]

I understand that 1967 was the sole year (or close to it) that 318s had closed-chamber heads until the 302 head came along later in the 80s.

My engine just rolled over 107,000 miles - I know that the valve guides are a little wobbly from when I changed the springs, and had use or not I'm sure the valve seats have seen better days (stem heights appeared equal but who knows what the actual sealing surface looks like).

I found Clearwater Cylinder Heads on eBay selling refurbed 302 castings for about $185 a pop, including valves. 68-72cc chambers. Supposedly there are some suppliers out there like CM Engines who sell for even less if you ask (this is according to a 4 year old post, though).

What'd be better worth my money - buying a pair of new 302 heads for around $400-500, or having my existing heads refurbed for that much or more? I don't know many machine shops around here nor what $500 would buy in good head work beyond guides/seats, or if 67s are worth messing with. Of course there's the wildcard 360 head but I still don't understand if it's possible to recover the lost compression on those with head milling alone.

There's a bazillion articles and posts and topics about 302s, but I haven't been able to find out much about the original '67 small block heads.

Inform me, please!

 

[RCAddict]

I'm not sure about the cc's on the chambers but you would save a lot of money using 302's versus having your heads setup for unleaded fuel. I believe the ports are larger than your original heads so an intake change is mandatory
I'm doing a Magnum head conversion now for my wagon
it's easier to get more lift from your cam using the 1.6 stock rockers that come on them & have smaller chambers as well as bigger valves that don't require cylinder notching

 

[Secret Chimp]

I'm running a standard Eddy Performer right now. I'd like to do a Magnum conversion but I imagine it would end up running me more money in the end with the extra changes needed to run it on an LA block. In the Northwest everything is a bit harder to come by or more expensive, or both, for Mopar stuff.

 

[Supershafts]

Is this a DD and also a 67 car or what... What exactly are you doing with what ?

 

[Secret Chimp]

67 Coronet wagon, original 318/727 drivetrain. Not a DD but used like one when it's driven (i.e. it's cruising more than it is going fast)

 

[Supershafts]

Then do the newer heads they'll already have better seats.

 

[Powerflite]

I already have a good running 318 motor in my '70 wagon, and I have a set of rebuilt 302 heads. My question is would it be worth going to the trouble to replace my stock heads while I am already changing the intake, or would the benefit be minimal and mostly a waste of time?

But if your current heads need gone through anyway, I would definitely change to the magnum or 302's.

 

[RustyRatRod]

First, the things I know.

As stated, I think Magnums are the clear winner over the 302s. They also have the small chamber, but also have larger valves, a 1.6 ratio rocker system.

Now for what I do NOT know.

I have had no direct dealings with Clearwater Cylinder Head. Like you, I am intrugued at their low prices. However, I have read nothing but bad things about them. I mean nothing but. That's not a good sign. They may well be reputable, I don't know first hand.....but at this point I would not take any chances.

 

[67Dart]

I'm not sure about the cc's on the chambers but you would save a lot of money using 302's versus having your heads setup for unleaded fuel. I believe the ports are larger than your original heads so an intake change is mandatory
I'm doing a Magnum head conversion now for my wagon
it's easier to get more lift from your cam using the 1.6 stock rockers that come on them & have smaller chambers as well as bigger valves that don't require cylinder notching

"302's" have the same small intake ports as 273/318 heads, and pretty much the same CC's as the early heads, so you can use your original small port intake. What you are gaining with 302's are swirl port chambers and hardened exhaust seats. The ports are a bit better, but probably won't be noticable on a daily driver.

 

[rumblefish360]

"302's" have the same small intake ports as 273/318 heads, and pretty much the same CC's as the early heads, so you can use your original small port intake. What you are gaining with 302's are swirl port chambers and hardened exhaust seats. The ports are a bit better, but probably won't be noticable on a daily driver.

This guy hit it on the head. A new intake is NOT MANADTORY

The 302 head will perform exactly the same as your current head does. The 302 head can be ported out much further than any other 273/318 head. This is why there recommended.