milling the head

mluck

Well-known member
the people that are going to work on my head are concerned about milling to much..i said .060...the head guy is worried about overheating and the head gasket not fitting right....he said even though hes been working on heads for 25 years ..hes really not that knowledgeable with upgrading theses heads.
 
then its time to give him an education. .060" is fine, but before you have him do that, run the numbers carefully and make sure you dont run your compression ratio too high for pump gas.
 
I second rbohms advise double crunch the numbers but in most cases .060 is plenty safe. I would also consider zero decking the block while you're at it, this gives the ol' six a real kick in the pants towards making decent power. If your still feeling rather leery about taking off .060 you can go .040 and still take up what thickness a new head gasket would offset you and have about .015 extra to squeeze. That's what i did on my econo build and the car runs great on pump gas.
 
mluck":qsq6d2wg said:
the people that are going to work on my head are concerned about milling to much..i said .060...the head guy is worried about overheating and the head gasket not fitting right....he said even though hes been working on heads for 25 years ..hes really not that knowledgeable with upgrading theses heads.
The head is a late model with the large log??
Also what camshaft are you running, is it the Comp. 260??
If both the above is correct take at least .060" & zero deck the block. Run a Victor head gasket which is .004" thinner than the Felpro & seals better.
If your engine has dished pistons your compression will be close to 9.2-9.4.
 
According to Ak Miller and the details on the new shell moulding processes at the Cleveland plant, after 1969, Ford started downgrading the iron thickness. For early heads, 90 thou is the practical limit, but you can go to 120 thou like FalconSedanDelivery did on both his head casting, and the block deck. Rocker geometry then has to be checked and adjusted.

After 1969, the average casting droped to 187 thou bluenprint at the Cleveland foundary, and for cylinder bores, they shell moulded down to 130 thou. Great if your making them, not so good if your reconditioning. Compared to a Chevy 283 or early small journal 327, the heads measure 242 thou everywhere,




with no less than 180 thou in the working face of the cylinder bore. Ford used to make engines like that, Y blocks, I blocks, FE's. Lima MEL 430 and 462's.....it wasn't a cost cutting measure made until Ford won LeMans, and then it came time to pay the rent. Less iron less cost. Its not an issue unless you really need a lot of compression.


60 thou for head planing for C9 heads to E1 heads, and 30 thou for overboring blocks. The 250 always had a lot of deck height, you can cut em down 120 thou, but block cracks around the head studs can occur unless some stress reliving is done.
 
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