2.0 merc heads

[bassinvol]

:confused: I have built 1 good motor from an "88 150 and an 135 that I don't know the year. The heads are both the 1 piece design but the ones off the 150 are hemispherical heads and the 135 had a flat top design. I first figured that the flat top design was a lower perfomance head until I rebuilt a friends 200 efi and noticed that the heads on it were the same flat top design. Question, is there any cc difference in the heads and which set will give better performance? This motor is on a '76 1640 Procraft bass boat that I completely rebuilt several years ago.

[T-REX]

In stock form, they ain't much differnce...If ya gunna cut them, tha Hemi head stands out because U kan git more compression with less cut...I personally like tha Hemi design, becauze it theory it works better...but, On tha stop watch, they ain't much/if anyu differnce!!...REX