Join Date: Sep 2004
Location: San Francisco Bay Area
Re: remove 0,1 inch from D3VE-A2A heads
I have never measured, but I would estimate the cylinder head mating surface to be perhaps 0.300"-0.400" thickness before any machining since delivered from Ford. The variation in the estimated thickness comes from potential core-shift and also because in some places there are water jackets and other places there may not be water jackets.
The cylinder heads are applied to the cylinder block with a final torque of 140 lbs/ft. I can't say for sure, but you may want to consider whether you want to risk going so thin as to cause your heads to crack when bolted to your engine. I really don't know for sure how likely this is, and it may not even be a factor in your proposed modification.
The D3VE combustion chamber is about 0.100" deeper in the cylinder head than the early-style castings. If you cut 0.100" from the chamber-side of the heads, you will need a new set of pushrods for sure, so as to restore rocker arm geometry. Further, your intake manifold will no longer fit to those heads, unless you either machine the manifold so as to mate properly to the heads OR machine the intake-side of the heads after machining the combustion chamber side. Can your manifold be machined at the intake flanges by .100 on each side? Is there enough material? Personally, I think it is better to machine the intake sides of the heads at the same time you machine the combustuion chamber side, because this way only one engine component (the heads) has been bastardized, and the intake will still work on the modified heads and unmodified heads.
BUT, the general rule of thumb is that if you shave .040" from the combuston chamber side, you should also shave .040" from the intake side so as to keep everything dimensiionally correct. But what if you need to shave 0.100" from the intake side? Will the intake manifold bolt holes still be deep enough to accomodate the bolts? I don't know....
All this modifying will not only be experimental, it will be expensive. And the results will be nothing better than simply buying a pair of early-style castings. Also, this expensive modification may not even work and the heads may be rendered useless. At least D3VE heads are plentiful...
The risk is yours. I'd sure like to hear how this works out...