what engine for my 68 911?

[adomakin]

just sold my 2.7s engine and im looking for an alternative. I was thinking 3 litre sc (204bhp) but someone said that they are real heavy and that a 3.2 would make for a better and more powerfull swap. ive got a 915 box installedand the car is currently looking like a 73 carrera with longer rear arms and rs rear arches and s brakes (though i still have to jump on them every time i want to stop!! can anyone advise??

Thanks.

Andy

[dd74]

Coming from a transplant history myself ('74 911/3.0), I would think the 3.0 would be the easiest and most cost effective to install in your car. It is lighter than the 3.2, but I think the difference is only about 25 pounds. That same 25-pound increase should be factored in between the 2.7 and the 3.0.

A 915 gearbox, particularly if it has a 7.3:1 ring and pinion will have a better survival rate with a 3.0 than a 3.2 - the torque in a 3.2 can put a strain on the ring and pinion if you do a lot of drag racing-type starts. Also about the 3.2, some flywheel work will be required to adapt it to the 915, though I am not all too sure what that work is.


As for reliability, 3.0s snap head studs (they don't pull like 2.7s), and yet 3.2s have been known to suffer valve guide problems. If you sold your 2.7, hopefully (if it had one and the engine wasn't sold with it), you can adapt your exhaust system from the 2.7 to the 3.0 for a higher horsepower/torque gain. This same exhaust system is a bit too small for the 3.2; for the same gain of the 2.7's exhaust system adapted to the 3.0, the 3.2 will need headers and a new muffler.

CIS on the 3.0 is not very adjustable in lieu of other modifications (i.e. pistons, cams, etc) that you might want to do to the engine. The Motronic system in the 3.2s can be chipped or an electronic aftermarket fuel management systems can be adapted to the 3.2 to compensate for piston and cam change.

Regardless of these details, either engine is a nice substitution for a 2.7.

[adomakin]

thanks for your help!