"302" heads opened up to 360 intake port size question.

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Dragonbat13

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Ok, I got this lump in my car. Its a 318. I had thought the engine was gone, but apparently its still in there and just needs a crank. Gonna find out in a few weeks.

But anyway, I want to try and fix it. I dont think its gonna be a problem with the crank. All its gonna do is move the car around. But if I can get it to run decent I will.

So it has 302 heads on it, but the intakes were opened up to 360 gasket size. And its not the best opening up. The runners sorta look like some inlets to velocity stacks. A real heavy, rounded pinch all the way around the port.

My question is, should I use a ebay special performer intake that has been opened up to 360 size, or just slap a stock one on and have the funky overlap between the ports? After all the overlap isnt going against the flow, the small side would be upstream.

I have also considered getting something like that putty epoxy steel stuf and replacing the material, then just filing down the gasket surface and using 360 gaskets to keep the sealing surfaces on the original metal of the heads.

I know the 302 heads arent that great, but I though about using super thin head gaskets to raise the compression and get a little more quench out of them.
 
The 302 castings are the best stock heads for 318's Also if you put a stock port intake on the mismatch won't be an issue. (Now if you had a 360 ported intake and stock ported heads there would be a problem.) A thinner head gasket will bump up your compression a bit too. Don't use the epoxy. JUst asking for problems there. tmm
 
302 heads work because they have great velocity and swirl port design. If you opened up the ports, you may have taken away the velocity which causes torque. 318's need torque unless you have a very high stall converter. Hope the porter didn't ruin the design that makes them so great. LOL
 
The grinding wasnt done past the pushrod pinch on that side. The best way to describe it is it was just opened enough to allow a 360 manifold to not have the mismatch.

I think I am gonna tear it down, do a basic rebuild that I wanted to do in the first place, use thinner head gaskets and a cam swap.

I want to say this engine had a roller cam also. I may do some searching on a cam. Car is a 74 dart/904 with 2.74 first,999 planetry sets/2500-2800 stall/3.55 gears or 3.23 (eventually it will get 3.55)/vaccume second four barrel/headman 1 5/8 headers and 2 1/4 dual exhaust. Any ideas on some general cam specs?

What about the head gasket? Always wanted to try those cometic, although they are rather expensive for a budget build.
 
If it was a good job and only the port openings, it won't hurt a thing.
 
Don't fit a small port port manifold to a head which has been opened up to the larger size. Where the incoming charge goes from small into big, you'll get tand eddy/turbulence which will create drag and reduce performance.
(I read that in a book, so it must be true)
 
All joking aside, I would think the the turbulance would help keep the fuel suspended.

As far as the epoxy, just how "unstreetable" is it. Probably not worth the effort on this build, but I know that puddy steel stuff in a tube is a **** to get off of anything. Not to mention the bragging rights. "Man, these ports are ported, polished, epoxied the runners in the right places. These heads are IT. You should see my car mash them taters!"
 
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