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302 heads vs 67 closed chamber heads on 318?

Posted By: Secret Chimp

302 heads vs 67 closed chamber heads on 318? - 07/16/12 05:46 AM

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!
Posted By: 340SHORTY

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 07:17 AM

Id buy the 302s, they are swirl port design and will flow a lot better..
Posted By: Dean_Kuzluzski

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 09:46 AM

Quote:

Id buy the 302s, they are swirl port design and will flow a lot better..




If you can find them as cheap as you say.........I agree.

But, you still have an unmodified head.

The closed chambered 67 head upgraded to 1.88/1.60 valves with a gasket match and bowl porting would be an interesting challenge to the stock swirlport design. I'm not saying it would be better, dunno, it just might flow better at top end. It's a bird-in-hand kind of thing.
Posted By: scratchnfotraction

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 10:57 AM

67 = non hardend valve seats

if you are going to buy heads have you thought about the mag heads with LA intake bolt pattern? EQ-heads IIRC and about the same price.

closed chambers,bigger valves,better port flow for untouched heads.

myself i like a 360 head on a 318 and shave .050 off for a CR bump,mild cam and lots more breathing on top end.

I did like the #302 head when I home pocket port and bump valves to 1.88/1.60 but still prefer the 360 heads over all.

the last set of #302 heads I just pocket ported the exhast side and bumped the valve to a 1.60 for a 1.78/1.60 valve set.
Posted By: Secret Chimp

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 04:38 PM

Would those LA-Magnum heads require anything beyond different pushrods?
Posted By: scratchnfotraction

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 06:48 PM

Quote:

Would those LA-Magnum heads require anything beyond different pushrods?




on a non roller cam LA engine...yes it is a magnum head with a LA intake bolt angle change.

it will need oil thru lifters/PRs to oil the magnum rocker gear.

this is why I like a pre-magnum roller cam LA engine, it has oil thru roller lifter/hollow PRs and oils like an older LA engine thru the head to the shaft rockers.

oiling both ways I would have thought it would have to much oil in the VC but not the case. most 90-93 318/#302 heads do it this way stock.

so I would be able to swap a set of mag heads right on with the stock magnum PR and have the older LD340 intake on it for a pre-mag hybrid 318.
Posted By: Secret Chimp

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 09:13 PM

Interesting. I didn't know you could get new/fresh-refurbed Magnum heads set up for use on LAs like that. I'd only heard of people buying used heads and then having them redrilled for the LA intake bolt angle during a normal refurb.

But still it sounds like I'd have to buy both the heads and a Magnum roller valvetrain for like another $300 from Comp or someone, right? It doesn't sound like my shaft-oil rockers on my current heads would transfer.
Posted By: scratchnfotraction

Re: 302 heads vs 67 closed chamber heads on 318? - 07/16/12 10:02 PM

correct,they will use the magnum pedistal mount 1.6 rockers and need the PR oiling. the magnum rocker/pedistals are fairly cheap for a full set at the dealer IIRC around 60$ for 16.

I have a few complete sets of roller valve gear from junking stuff.PM me if you need something for stock roller valve gear.

I am working on getting a set of the EQ heads for a hybrid build. I am stroking the 88-318 with a 360 crank for a 349 stroker with magnum heads/LD340 intake and voodoo roller cam
Posted By: BulletBob

Re: 302 heads vs 67 closed chamber heads on 318? - 07/17/12 02:28 AM

You have to grind the casting flash out of the pushrod holes in the heads The pushrod length seems to vary between 7.625 & 7.650
Magnum heads are the way to go
I'm doing a stock block 360 with Magnum heads,Crosswinds intake & Purple Stripe Ccamshaft for my wagon
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