X head milled to closed chamber ?

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Did this a dozen years ago--chambers came in at 45 cc I believe. Beware your piston valve reliefs will have to change to accommodate. J.Rob
 
Wouldn't it have been nice if they had made some like that?
 
Why, just buy good pistons?

Yes! :cheers:

You will also have to mill the intake to match the heads, and then figure out pushrod length, and/or shim the rocker arms... One headache after another... :banghead:


I agree, just buy the proper set of pistons... :D
 
Did this a dozen years ago--chambers came in at 45 cc I believe. Beware your piston valve reliefs will have to change to accommodate. J.Rob

Got any test results? That head should help resisting detonation with it's closed chamber. Would
work well on a 318. Machining costs would be the downside.
 
I have been pondering this exact thing for a few days now, only for a big block. I may just spray weld the chambers then mill them to create a closed chamber 906 or what ever. Just changing pistons will not gain the desired quench you get from a closed chamber. I'm thinking my pistons are too far in the hole for good quench anyway, but I could gain a little in compression, which the cam may drain off anyway. And so goes the vicious cycle with it's myriad of variables. I shall persevere and overcome, or I will just build a 280hp 440 that will run forever. Skinny tires should get me the smoke I desire.
 
Just found it interesting. Kind of a fools endever these days.

I always want the thickest decks, the thickest bores, thickest head surface, highest valve seats. By milling that much off the head surface, I was always afraid of blowing head gaskets or worse. 340 pistons are above block at 10.5 to 1. Those heads do look sweet.
 
I have been pondering this exact thing for a few days now, only for a big block. I may just spray weld the chambers then mill them to create a closed chamber 906 or what ever. Just changing pistons will not gain the desired quench you get from a closed chamber. I'm thinking my pistons are too far in the hole for good quench anyway, but I could gain a little in compression, which the cam may drain off anyway. And so goes the vicious cycle with it's myriad of variables. I shall persevere and overcome, or I will just build a 280hp 440 that will run forever. Skinny tires should get me the smoke I desire.

Custom pistons would probably be cheaper. 1967 915 heads are closed chamber as are 516's. The 516's in stock form will loose to the better flowing 906's. Search IQ-52's low compression 440 build. If you know the right combination, you can get a lot more than 280 HP, open chambers and all.
 
Also, rest assured whoever milled that head up there ^^^^^ had to angle mill it. Technically, they angle milled it the wrong way. Angle milling is used to get the valves on a better angle with the pistons and chamber. The intake side would have had to take the heaviest mill there and that's goin slap the wrong way.
 
Custom pistons would probably be cheaper. 1967 915 heads are closed chamber as are 516's. The 516's in stock form will loose to the better flowing 906's. Search IQ-52's low compression 440 build. If you know the right combination, you can get a lot more than 280 HP, open chambers and all.

I am aware of that build. And I do have a pair of 516's to work with. They would need porting and larger exhaust valves. I may copy the build. Only thing is I really would like to run stock hp exhaust manifolds and I'm guessing I will loose a significant amount of power. I do have a set of headers I can use if it doesn't satisfy me.
 
the 516 head has way smaller intake ports. even ported , they will not come close to a stock 906 head!!!!! 184 cc vs 203 cc. not worth the effort. seen them on flow bench!!!
 
the 516 head has way smaller intake ports. even ported , they will not come close to a stock 906 head!!!!! 184 cc vs 203 cc. not worth the effort. seen them on flow bench!!!

Probably true. Would be better suited for a 383, if at all.
 
yes! :cheers:

You will also have to mill the intake to match the heads, and then figure out pushrod length, and/or shim the rocker arms... One headache after another... :banghead:


I agree, just buy the proper set of pistons... :d

^^^^^^^^this!!!^^^^^^^^^^^^
 
I don't like cutting heads a lot cuz u lower the ports - not good for power. my 340 has .050" quench with open chamber 3418915 J heads
 
I did this to my 894D x heads. I milled them .35 thou and got a 60cc chamber. They were still open chamber slightly
 
I have been pondering this exact thing for a few days now, only for a big block. I may just spray weld the chambers then mill them to create a closed chamber 906 or what ever. Just changing pistons will not gain the desired quench you get from a closed chamber. I'm thinking my pistons are too far in the hole for good quench anyway, but I could gain a little in compression, which the cam may drain off anyway. And so goes the vicious cycle with it's myriad of variables. I shall persevere and overcome, or I will just build a 280hp 440 that will run forever. Skinny tires should get me the smoke I desire.


Could you explain this posses to me, in more detail...............
 
I have been pondering this exact thing for a few days now, only for a big block. I may just spray weld the chambers then mill them to create a closed chamber 906 or what ever. Just changing pistons will not gain the desired quench you get from a closed chamber. I'm thinking my pistons are too far in the hole for good quench anyway, but I could gain a little in compression, which the cam may drain off anyway. And so goes the vicious cycle with it's myriad of variables. I shall persevere and overcome, or I will just build a 280hp 440 that will run forever. Skinny tires should get me the smoke I desire.

It will be much more budget friendly to simply find some 915 heads. Even perhaps to buy a set of aftermarket aluminum closed chamber heads.
 
Google spray weld.



I did, just can't see how it would hold up in a high heat/pressure situation like a head live in.

just wounder if any on had done this on a actual head......and did it live................

Sorry Getting this thread of in the wrong direction.......just curious
 
I did it in a restricted racing class with flat top KB pistons ON A 368CUBE 500cfm carb rule. all the intake seats cracked to the spark plug hole in every cylinder, and I was using race gas for 12 to1 or higher. rich carb and never went over 180 degs. and 32 degs timing, they were the x heads,894 69 head. but they did go about 250 miles at full throttle before I found the cracks. might hold up a full season in 1/4 mile racing or on the street with limited fun time. also the rocker oiling hole had to be reworked to keep the oil flowing.
 
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