Thread: drag engine build

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Flat top pistons with those heads will give you about 9.2:1 compression ratio. I feel this is too low compression for the camshaft you intend to use. You will need dome top pistons to increase compression or you will need to change your head choice to that of a smaller combustion chamber volume.

If you switch to the early-style head (C8VE, C9VE, D0VE) you will increase compression ratio to almost 11:1 with the flat top pistons. This compression ratio is better suited for your camshaft.

Between changing pistons and changin heads, the head change is technically a better way to go because the flat-top pistons will be lighter than the dome top pistons, but either way will work. Valve train mods are also required of the D3VE cylinder heads, unlike the early style heads mentioned above.

Also, if the KB's are hypereutectic pistons, then you may want to consider forged pistons for a motor that will be seeing regular abuse. 3500 rpm souds like quite a high stall speed even for this motor in that car...are you sure you need that much stall?

Finally, the stock rods are marginal in high rpm/high HP applications. You will be pushing the limits of those rods and should at least prep them and put in some quality rod bolts. Aftermarket rods would be a better choice.



Paul