340 Heads, What's What

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Thanks, your probably right that they will work fine since I'm not building a race car here.I'm not seeing any pollution pump holes on these heads like later model 360 heads. My 340 is a 1973 and the heads look to be original with the motor, this motor is in my 71 road runner and looks to have been with the car for many years now, but needs a rebuild. I just want it to perform as well as a stock 71 340 does. I know that I will need higher compression pistons. Any more opinions?

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Can anyone tell me what those small holes below the regular exhaust ports are for on the 78 360 heads, do they have to be filled with jb weld? can i do it with the motor already installed in the car? I just noticed those after putting on a set of 340 hi-po manifolds, the regular 360 manifolds covered the holes.

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Hey folks I have a set of 587 casting heads w/1.88 intakes for my 340 engine that I plan on rebuilding back to basically stock 1971 specs. How do these heads compare to the 915 infamous "J" heads. Is ther really any diff other than some 915 heads have 2.02 intakes. Thanks for any input.

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They will run als well or better than the 915 2.02 heads till you start to spin in the 6000+ RPM range. The smaller valve will actually most times give you better low end. Too many blame the heads for the lower power output of the later 340 heads when in fact it was a combination of other things that did it, big thing being lowering the compression ratio big time.