Hi Mark,
I had around 1/8" removed total (From the head and block) and I have to
use 91 octane and it still will ping. I dont know about 1972, but the
'69 engine I have came stock with a 9:1 or 9.5:1 cr, so Im probably
running a ridiculous compression ratio right now. The only reason I
took this much off was because I had the head milled years ago and then
once more trying to solve a leaking head gasket, but that didn't fix it
so I had to get the block decked also. The motor pulls pretty good, but
I wouldn't recommend shaving too much. I need to get myself a thicker
head gasket and different length push rods some day soon...
My $.02.
Eduard Tieseler
'66 Herald
Mark.Green@communityhospital.com wrote:
>I live in a state where my '72 Spit doesn't need to pass any emissions
>testing because it's a pre-1975 model so I was thinking about increasing my
>engine's performance. Part of what I want to do during the winter
>non-driving months is increase my compression ratio by milling the engine's
>cylinder head (along with porting and polishing the head). I have a basic
>1300 engine with a single Stromberg and was wondering how much could be
>milled off and not cause any problems with the 91 octane gasoline we have
>in the USA. I have a local auto machine shop and the owner could easily do
>it during the snowy winter months.
>
>Anyone ever had this done and could give some feedback?
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