i have a set of holley aluminum heads and was thinking of putting them on my 92 z they have 68cc combustion chambers. will this hurt the comp. ratio? i also will be putting my slp 1 3/4 headers on at the same time. i know ill have to modify the center intake bolts. any thing else to watch for?

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92 z28 170,000 miles 14.20 on goodyear eagles only mods k&n and muffler fell off!
87 trans am 12.20 on motor too many mods to list

 

Yes the 68cc chambers will hurt your comp ratio considering stock is 64cc. You want to have them angle milled to 58cc. Hope this helps.

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N/A 406, TPIS Miniram, 58mm TB, 30lbs injectors, Custom Ground Elgin Cam, Ported TFS heads, SLP 1-3/4", & DFI computer.
11.70@117mph

 

why to 58cc if the stock are 64?

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92 z28 170,000 miles 14.20 on goodyear eagles only mods k&n and muffler fell off!
87 trans am 12.20 on motor too many mods to list

 

To gain more compression. Something in the 10 something neighborhood. Aluminum heads can handle more compression since they can disperse heat a lot better. Besides.. more compression gives you more power, plus it allows the engine to use those heads to their full potential.

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92 Z28 5.7
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Trick Flow 23° heads, Comp Cams XR270HR-10 cam, Accel intake base + ported TPI,
TES headers, Flowmaster catback, MSD ignition, #24 SVO injectors, 1LE aluminum driveshaft.

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