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[jon1550]

I have an '02 Deuce with an '06 factory SE 103-B motor producing 96.20 HP/102.46 TQ
with no headwork. This current build includes Andrews TW55 cams, Zippers 50mm TB,
Thunderheader 2:1 pipes and SE Pro Super Tuner. Since Andrews recommends a minimum
of 9.8 CR for the TW55, I plan to have the heads street ported to raise Static Compression
to 9.85:1 (and Cold Cranking Compression of 185.2 @ sea level). Playing around on the
Big Boyz Compression & Displacement calculator, I can reach 9.85:1 by either milling 88 cc's
using .030 MLS head gaskets or milling to 86 cc's using a .040 MLS head gasket. As a novice,
does it matter performance wise, and does either approach have the potential to harm the
fins or casing? Hoping this mild porting job will produce a 10% increase to 106 HP/113 TQ
without overheating/detonation issues (since I commute regularly on days above 45 F).

[cherryseeg2]

Just got my heads back from Bean at bigboyz and had my compression set at 10.1.  I had no induction fitment issues.  If you have any questions Bean is a great guy to work with just give him a call.

[HILLSIDECYCLE.COM]

I have an '02 Deuce with an '06 factory SE 103-B motor producing 96.20 HP/102.46 TQ
with no headwork. This current build includes Andrews TW55 cams, Zippers 50mm TB,
Thunderheader 2:1 pipes and SE Pro Super Tuner. Since Andrews recommends a minimum
of 9.8 CR for the TW55, I plan to have the heads street ported to raise Static Compression
to 9.85:1 (and Cold Cranking Compression of 185.2 @ sea level). Playing around on the
Big Boyz Compression & Displacement calculator, I can reach 9.85:1 by either milling 88 cc's
using .030 MLS head gaskets or milling to 86 cc's using a .040 MLS head gasket. As a novice,
does it matter performance wise, and does either approach have the potential to harm the
fins or casing? Hoping this mild porting job will produce a 10% increase to 106 HP/113 TQ
without overheating/detonation issues (since I commute regularly on days above 45 F).

The thumb of rule, is .007" equals 1 cc, but the "check twice, cut once" method, applies to this.
Use the .030" by all means, as the closer you can put the piston to the cylinder head, without contact, during normal operating temps, the less chance of detonation you'll experience.
Singh grooves also help.
If you so desire, call us at the shop, 315-495-6650, and we will push your combination through one of our engine programs to alert you to the EXACT compression needed, still within the confines of pump gas, to fully expose the worth of that combination.
My thoughts on the air requirements of that engine,(we average about 150 sets of heads a year here) to bring the hp/torque WAY up, would be a head that flows at/near 165 cfm, @ 10"/.600 lift, with it GULPING air, at lifts as low as .100".
No problem bringing 103"s to at/near 120/120, with the proper combination.
Scott

[HD Street Performance]

Scott
This has open chamber heads. 98cc

[HILLSIDECYCLE.COM]

As Don has pointed out, the 7cc rule is out the window on that one.
Can't slip nothin' past you.
Scott