I'm currently running a 170 slant, and want to have the head milled. I've read in other forums that 170's are diffrent because they are a zero deck motor so milling the head in it is diffrent than the 225. I'm wondering how far or what other 170 slant owners have taken thier heads down, and how far before you run into push rod length problems. Any help is appreciated!

The head for the 170 and the 25 is the same, and can be milled the same amount. The difference with the 170, as you know, is the deck hight, which makes the piston to valve clearence more critical. You need to take into consideration the cam specs, on the 170, more so then on the 225. I have .100 off my head on the 170. I was very limited on my cam choices, without notching the pistons. I also had to use shorter pushrods, but just barely. That will depend on OEM manufacturing tolerances. If the cam you use, is a regrind, it will had a smaller lobe base circle, and the odds are more in favor of std push rods fitting. I also run the OEM steel shim head gasket. If a aftermarket, thicker) head gasket is used, the compression will be lower, and valve to piston clearance will be greater. What ever you do, with any motor, you should always check these clearences. What works on one mortor, may not work on another, due to OEM tolerances.

PS: my 170 started out with about .020 deck from the factory. If I had not milled the block, to make this .002, and had used a aftermarket head gasket, I think the stock pushrods would work.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225