CIS to PMO, engine drop required?

[ael911]

I am thinking about switching from CIS to a new set of 46 PMOs. I understand that PMOs come with the complete install kit. Can the conversion be done with the motor in the car or does it require a motor drop? From reading Wayne's book, I know the CIS unit can be removed as a complete unit once all the manifold nuts are removed and connectors disconnected. Anyone that has done this conversion please chime in.
Thanks,
Andy

[JP911]

I did the CIS to PMO swap this past summer and did not drop the motor. The CIS runners need to be detached from the airbox to get everything out. It's a pretty easy job. I hit two roadblocks (neither having to do with the CIS): 1. PMO did not send the longer studs required to bolt the manifolds to the heads with the spacers, and 2. I had to cut some material on the fan shroud to make the spacers fit.

By the way, won't 46s be a bit much for a 2.7?

[ael911]

Thanks JP,
Yea, 46s are a bit optimistic for a 2.7. I think 40s would be the ticket. I know this has been a great debate, but did you see any increase in hp? I am sure the throttle response was better. What's your take?

[JP911]

I was originally running CIS on my 3.5, but the engine ended up in a smog exempt car. The CIS was really choking off the motor so it's a completely different experience with the PMOs. With the carbs you'll get the throttle response (which is really nice) and you'll be able to bump up your ignition advance for a bit more power. What would definitely give you more power is a hotter cam matched with the carbs. I'm tossing around the idea of a cam swap to get the most out of my setup.

[Steve@Rennsport]

Jon is correct; 46's are FAR too much carb for a 2.7.

The 40mm PMO is just perfect for your engine and leaves plenty of room for growth, should you decide to change pistons & cams.

A properly setup & conrfigured PMO package makes a huge difference in throttle response that belies the actual power increase,...

[81 911 SC]

I have 40mm PMO's on my 3.0 SC running standard SC cam and recurved distributor. throttle response is much better. If you're still looking for good/reasonable MPG then don't go with carbs.