198 slant questions

RustyRatRod said

I haven't seen anyone talking about piston to valve clearance yet, until you brought it up. We were discussing how you can take lots of material off and still get decent valve adjustment. I don't know if it's possible to make a 225 or 198 make piston to valve contact by milling. I guess it's possible. I know on the 225 in Vixen right now, the deck clearance was .175 in the hole. Ridiculous. I had the head milled to get the chambers from 56cc to 34cc. That was well over .155". This engine has a tic over 175 cranking pressure. On a slant 6.

Click to expand...

I have a 74, 225 here on a stand that I am slowly putting together as time allows, and even after a 30-thou deck shave, my pistons are STILL at 180 thou in the hole. I'm not really happy about that. It has 20-over silv o lite stock style replacement pistons in it on a set of NOS OEM Mopar rods I found via a guy over at the /6 forum.
I started with a head a block and a crank. Didn't get Pistons or rods with it when I got it or I'd have measured how deep in the hole the originals were.
So if I hadn't asked for that deck shave they would have ended up .210in the hole. Really ridiculous huh?
One of the magazine articles I read on the /6 had a fresh engine with Pistons at .210 in the hole. I think it was an article about the red 67 dart at the college in PA. There have been a few written about that one.
I've heard it said that replacement piston makers make the compression height less to compensate for the (slight) potential CR increase from boring out a cylinder. Which might be/ but is even made more ridiculous when you consider that when actually measured out/"blueprinted" as they come from the factory they aren't anywhere near advertised compression ratio to begin with due to all the tolerances of an assembly line.