Re: pistons & valve lift

[Andy Kress <aokress@xxxxxxxxxxx>]

I don't know the exact limits of FP limited prep rules so I don;t know how 
much you can modify - head thickness, pistons (do they have to be an OEM 
offering?) can pistons go to .040" over?.
Motronics are 10:1 w/ stock head thickness, as Jeff stated, and by all 
accounts (probably all anecdotal evidence, no test data) the Motronic 
pistons are superior to the 10.4:1 old style pistons.  they are alleged to 
give better flame front propagation, quicker & better burn, etc.  so i 
guess on the surface - 10:1 should be enough.  However, if cam timing, 
duration and overlap are left wide open - then dynamic compression ratios 
will vary widely w/ the cams selected- the more static compression you can 
get (or more precisely, be allowed to chose from) the better.  If you can 
go aftermarket and use .040" over pistons - Paul Spruell sells an 85mm 
forged piston that can be ordered in an 11:1 ratio.  I believe there is 
enough metal on top that some could be shaved off if you end up needing to 
come in under 11:1.  I'd ask for as much as you think you can get from them 
- more.
As to cam lift - If they'll give you 11.43mm - take it - the more lift the 
better.
Especially if you are going to petition for OEM Injection - Wes Ingram has 
some pretty good cams available w/ lifts up to 13mm.  I'm sure he can help 
you come up w/ an 11.43mm lift cam w/ best duration & overlap. I'm also 
sure there are others out there w/ selections in the 11 -12 mm lift 
category.  Kent Cams, C&B, Alquati for instance all list cams w/ lift 
greater than 11 mm.  I'm sure there are others.
Good luck w/ the petition!
Andy Kress 
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