Compression too high?

[Belgium Cuda]

The strokerbuild for the charger is about to start but the compratio is 10.9 according to 440source, isn't that
a little bit to high? I will use the eddy heads and a engle K60 camshaft.

[heminut]

Not with aluminum heads. General consensus is that you can run one point higher with aluminum than you can with cast iron heads. You should be fine with pump premium.

[73Chally]

Not with aluminum heads. General consensus is that you can run one point higher with aluminum than you can with cast iron heads. You should be fine with pump premium.

However, 10.9 is pretty much the max even with aluminum heads.

[Moparal]

   I'd love to have those SRP .030  not to high for me

[Chryco Psycho]

Make sure you have quench you are eqivalent to approx 9.9 with iron heads & you have better fuel , 96 octane I believe so no issue with compression , & would make sure the quench is in the .040 --.050 max range even if the compression is slightly higher this way as it will kill the detonation

[MEK-Dangerfield]

What octane is premium gas over there in Belgium? 

[Belgium Cuda]

Chryco,
How do I achieve this quench?

MEK,
We have 95 and 98 in the gasstations, however on many European Musclecarforums it's discussed if we use the same formula
and if the difference in reality is that big towards yours 91 octane. Hopefully some other members from overhere knows moore.

Since I have limited knowledge of precision tuning and building the Charger for a few cruising per year I have no problem to decrease
the comp a little bit if that makes my engine "easier" to handle. I guess a 500 stroker has torque enough.

[cudabob496]

I think a higher duration cam can help to prevent pinging, or detonation, or whatever you call it.

[Belgium Cuda]

I think a higher duration cam can help to prevent pinging, or detonation, or whatever you call it.

The Engle K60 has 288 duration

[nivvy]

with my edelbrock heads I was 10.92 to 1.. solid roller 248/254 @ .50    i ran pump gas 93 never tried any other grades.... 

quench was .052

[Chryco Psycho]

Quench is created by getting the flat part of the piston on the other side from the valve within .060 preferably closer to the .040 minimum clearance of the head so if the piston is .018 under the deck you need a .022 thick head gasket so the quench is achieved , or you can have the piston .005 under the deck & use a std 1009 FelPro gasket with .38 commpressed thickness  but I don`t recommend composition gaskets under Alum heads ever , Cometic sells a steel shim 3 piece MLS gasket  in different thicknesses to control compression & quench

[lemming303]

Chryco, why not composition gaskets?

[Belgium Cuda]

Quench is created by getting the flat part of the piston on the other side from the valve within .060 preferably closer to the .040 minimum clearance of the head so if the piston is .018 under the deck you need a .022 thick head gasket so the quench is achieved , or you can have the piston .005 under the deck & use a std 1009 FelPro gasket with .38 commpressed thickness  but I don`t recommend composition gaskets under Alum heads ever , Cometic sells a steel shim 3 piece MLS gasket  in different thicknesses to control compression & quench

Achieving this quench is in fact raising my compratio then but should be no problem? The 10.9 is calculated with .018 under
and a .039 gasket.

[Chryco Psycho]

increasing the compression ratio slightly to get better quench will pay off , the quench effect in the chambers will reduce the detonation more than the lower compression , you are basically splitting hairs anyway as the quench is in the range & the compression will not go up significantly using a .018 thinner gasket

[Chryco Psycho]

The composition gasket doesn`t live well with the drastically different expasnsion rates of Alum & Iron , this is why every 2.2 / 2.5 engine needed the head gasket changed just about as often as tune up / spark plug changes , even the awesome 1009 FelPro gasket doesn`t live for me , the solution is the Cometic MLS gasket with 3 steel layers allowing expansion by allowing the steel shims to slide instead of tearing at the fibers of the composition gasket ultimatly failing the gasket