Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec MAX CC'ing of 2.5 heads?

Well, sorry for taking up the forum with all these new threads, but hey, that's what it's here for, right?

Anyway, I need your input to help me decide which heads I will use assuming I DO elect to go 3.0 upgrade. Anyone know what lowest reasonable CR I can expect by having my heads CC'ed (how much can they be CC'ed)?

I hope know one is confused by my various questions regarding the route choices I suggest (in previous posts), but its's a matter of final cost and IF/THEN's. Meaning if I do this, then I might as well do that ... My various solutions are costing anywhere from $1500 upwards of $5k.

taking material OFF the heads deck will INCREASE compression. If your just opening up the CC then you can probably dip a tad below the stock 10.0 or 10.2. IMO, if you want to drop compression, go 3.0L.....just go 3.0L heads anyways.

Thanks Ryan, since it appears reasonable that I can hit somewhere around the 10 area, I will do a cost analysis between using one over the other. I agree with the idea of going the 3.0 heads a long as I can hold back from basically doing nothing to them outside a normal rebuild (assuming I can find some decent used heads , preferably low milage) On that subject, anyone know if there have been any changes to the '01 + heads with regard to compatibility with the mid' 03 up shortblock? I kind of pieced together through my parts searches that there may be a difference in part numbers for the heads on the two shortblocks (or maybe it was just the vehicle application)?

Full Oval Port 3L 'nuff said

After installing 3.0L valves in my 2.5L heads, along with quite a bit of deshrouding, I ended up with between 47.0 and 47.3cc. Accounting for the headgasket and all, that equates to a 10.43-10.49 compression ratio.

Somehow I recall a 11.2 CR if the 2.5L heads are installed untouched. That would be 43.2cc

The 2002 3L heads untouched were 49.0 cc, yielding a 10.14 CR.

While I ended up flowing about the same as the siamesed 3L heads with my porting 2.5L heads, fully ported 3L heads would have further gains.

3L heads are the easiest option.