318-3 Closed Chamber Truck Heads

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70coupe

70coupe

G'day from Downunder!
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Gidday FABO'ers

Recently I found a pair of bare NOS 318-3 Truck Heads.
These use a different spark plug to normal LA heads and the only other mjor difference I can see is that there is a water jacket entry in between the intake ports (where the exhaust crossover would normally be).

I'm hoping to use these on my build, does anyone know any other differences or reason that I should not use them?

Pics below

Your experience and insights appreciated

Pete

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Not a water jacket. IT'S a exhaust crossover.
Closed chamher heads !!! Great score.
 
What that head is missing is the half moon exhaust heat relief above the heat cross over passage. There is no water port there on any stock head.

Should you use these on your build?

What are you building and what is it being built for? What is the intended useage and HP output?

Oh! What spark plug do they use?
 
TXDart said:
Not a water jacket. IT'S a exhaust crossover.
Closed chamher heads !!! Great score.
Click to expand...

He may be right about that. Chrysler did that with their early Hemi truck heads. I have a set on my 56 331 Hemi on the stand in my shop. They also did it on some of the big block heads on medium duty trucks. It wouldn't surprise me one bit to see some 318 heads with the exhaust cross over re-cast as a water cross over.

Especially in Australia. They got all kinds of interesting twists on American parts. The Australian Ford 351 Cleveland is a fine example of that.
 
It is 1,000 percent a water jacket. I'll get pics later to demonstrate.

I have a '68 318 for my dart replica (Aussie Valiant Hardtop) Running a 4spd and 3.23 LSD

Stock bottom end, performer intake, extractors and dual pipes.

Other than the closed chamber heads thinking an XE256 or 268 Cam, 600 vac sec holley.
 
This is indeed into the water jacket. Ma did the same thing on some heavy RB engines

This is a photo of an RB just as an example. These are the ones used the "high mount" oddball water pump with the water ports on fronts of the heads. Notice the temp sender LMAO. Notice the odd canted plugs, which are "Ferd style" 18mm

water.jpg
 
So I guess my real question, does anyone see it as a problem to run water through an Edelbrock performer (Non-EGR) crossover instead of exhaust. Assuming I seal the gasket nicely I don't feel it will cause any issues?.
 
Can I ask why you would want to use those heads? I get close chamber heads raise compression, but close chamber heads don't flow as well, and that old of head would not have hardened seats.
 
70coupe said:
So I guess my real question, does anyone see it as a problem to run water through an Edelbrock performer (Non-EGR) crossover instead of exhaust. Assuming I seal the gasket nicely I don't feel it will cause any issues?.
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I don't know. I would use good composition gaskets and SEAL them around there.

So far as hardened seats I would not bet on that. Those heads were MEANT for hard, heavy pulling and to withstand HEAT. That was their purpose
 
318willrun said:
Can I ask why you would want to use those heads? I get close chamber heads raise compression, but close chamber heads don't flow as well, and that old of head would not have hardened seats.
Click to expand...

My 56 331 truck engine had hardened seats right from the factory in 1956. I've found verified proof all over the internet. And I don't mean induction hardened, but sho nuff hardened inserts. It would not sprprise me if those heads had the same.
 
RustyRatRod said:
My 56 331 truck engine had hardened seats right from the factory in 1956. I've found verified proof all over the internet. And I don't mean induction hardened, but sho nuff hardened inserts. It would not sprprise me if those heads had the same.
Click to expand...
Could be.... but it would surprise me if the ones pictured are hardened.
 
318willrun said:
Can I ask why you would want to use those heads? I get close chamber heads raise compression, but close chamber heads don't flow as well, and that old of head would not have hardened seats.
Click to expand...

I want to use them because I have them. Alternatively I will just use STD 318 small-port open chamber heads which have the same flow characteristics/restrictions.

If I use them I will have the seats done, just like I'd have to on any LA cylinder head available in Australia.
 
"-3" 318 truck heads do have a water cross over in the centre, 18 mm spark plug holes and closed chamber design. This design was used well into the 70's so could have hard seats.
 
Those look like pressed in seats with their little parting line showing. I bet the Performer would not even notice water in that port instead of exhaust gas. But some OEM EGR intakes did have EGR ports on the plenum floor for some stupid reason to dilute the intake charge. IIRC the B/RB water heads had the ports on the front with a unique water pump up front. Some guy on H.A.M.B had some from a 67 truck and his info said they were not interchangeable without the water heated intake but that may have been stock stuff. supposed to have sodium valves too. I bet youll be good.
 
Yeah they have pressed in seats both intake and exhaust.
 
pishta said:
Those look like pressed in seats with their little parting line showing. I bet the Performer would not even notice water in that port instead of exhaust gas. But some OEM EGR intakes did have EGR ports on the plenum floor for some stupid reason to dilute the intake charge. IIRC the B/RB water heads had the ports on the front with a unique water pump up front. Some guy on H.A.M.B had some from a 67 truck and his info said they were not interchangeable without the water heated intake but that may have been stock stuff. supposed to have sodium valves too. I bet youll be good.
Click to expand...

On closer inspection it does have exhaust seat inserts.
Cleaned off some of the 40+yo Ma Mopar Machine oil and hey, presto!

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I'm going to tear down the engine during the week, I'll go over/ compare the heads with a fine tooth comb next to the STD 318 heads and make sure there are no other differences (galleries etc). Intake bolt angles work with the performer so that's one problem avoided. If all else matches up I'm going to take a gamble and use them. If I run into problems with it leaking, I'll get the manifold welded and machined down the track.
 
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