Which heads for a 318? (I got two pairs)

[Loa]

Hello,

Currently, the heads on my 318 (on 68 Charger) are the 4323345 Police heads (1.78 intake, 1.50 exhaust, about 74CC, but correct me if I'm wrong).

I also have a pair of 3418915 (the 360 version) standing by. They're 1.88 intake, 1.60 exhaust and about 70CC, but again correct me if I'm wrong).

Would switching the heads make a significant difference in power? And if so, would it be as simple as swapping them?

Thanks.

[PRH]

Dimensionally and functionally the 345 heads are like "360" heads, although I don't know that they ever came on 360's.
From what I can find, they "should" have 1.88/1.60 valves.

Years ago I had one of those heads I was using to play around with on the flow bench, and that one did come with  1.88/1.60 valves.

Similarly prepped 915 heads flowed better..... and if the chambers are smaller, that's another plus.

With either of those heads on a stock 318 it's pretty easy to end up with compression ratios at or under 8:1.

[Loa]

Hello,

Thanks for the info. That's what I was afraid of.

I think I'm ready to keep the 318 and add better heads, cam and intake to get more power, instead of changing to a bigger block.

Could you recommend a new set of heads (new heads, as finding heads in junkyards is pretty much impossible here) that would push compression ratio closer to 10:1?

I'm not looking to build a monster. Something around 250 -275 hp would be ok for me.

Thanks.

[Nacho-RT74]

302 heads are closed chamber. If you wanna stock replacement, those are the best bid to increase compression rate. They are from 80s SBs. Called "swirl port" heads.

[Loa]

Thanks, I'll look em up.

But I'm opened to non stock heads as well (I'll keep the police heads if I ever wanna go back to a pure stock look).

[PRH]

If you're looking for a very noticeable improvement in power, my advice is to not try and make the 318 into something it's not...... a "high performance" engine.
While doable, it's not really very cost effective.

IMO, The best money you can spend will be finding a decent rebuildable 360 short block core.

[Loa]

Well, I thought so too until I found this article by the motortrend bunch from way back when in 2004.

http://www.hotrod.com/articles/318-small-block-build/

As I said, 250-275 hp is plenty for my taste and needs, and they got 400hp on a 1500$ budget.

Now I know I'm going to by heads, so it's going to cost more, but still...

[PRH]

If all you're looking for is 275hp..... you don't need much for that.

Have the 915's gone through, mill to 60cc, comp 901 springs.
Thin head baskets, comp 268h cam, std performer, 600 carb, headers.

[Loa]

Thanks for the parts list!

Two questions:

For the standard Performer, does the Edelbrock Performer Intake Manifolds 2176 fit the bill?

For the cam, does it have a nice lope at idle?