Webers or stock

[70SWT]

I've put my hands on a good 1975 2.7L 7R-based engine for my 72 widebody project (courtesy of another Pelicanhead who shall remain nameless, thanks). I also have read through BA's and Wayne's books to get some ideas. Bottom line, any comments on experiences with Webers vs. sticking with the stock injection for a street driven car, with occasional DEs and autox? I understand from BA that I can expect a HP increase but mileage will drop to the 16-19 mpg range.

[Wayne 962]

If you leave the engine stock internally - stick with the CIS. If you use higher compression pistons and a hotter camshaft, then go with Webers.

-Wayne

[70SWT]

Is it fair to say that without internal mods there would not be a significant increase over stock in using the carbs? i.e., you need the upgraded internals to take advantage of any gain from the carbs?

[Steve@Rennsport]

It really comes down to what you want and expect.

Instant starting and best mileage?...CIS, for sure.

Snap-your-neck instant throttle response and better power?...Its hard to beat a well setup set of carbs, even on a totally stock 2.7.

The operative word here is "well set up". If carbs are not properly done with accurate fuel pressures and float levels, they can be frustrating. If they are done right, its really an amazing experience,...

I've not needed to touch my Webers in 25 years so their reputation is all about the "human factors". Its instant start and go,...anytime.

[jgparker]

I second what Steve said. Webers on a stock 2.7 is very good. Webers on a HC hot-cam 2.7 long-block is awesome. If you're worried about gas mileage or your rebuild budget, stick with CIS.

Good luck,

JP

[70SWT]

The former 944 Turbo owner still in me tends to never be happy knowing there is more power to be had. I will probably end up wanting more oomph than I'm likely to get with the stock set-up.

As long as I have the engine out of the car, I may just go for the package as described in Anderson's book with 911E cams, Webers, etc.; the dyno results he lists puts the HP at about 225, which would be very nice. No idea what this is likely to cost me, gotta do some research...

[Wayne 962]

Go with the 'S' cams - the motor won't be as peaky as the 2.4S or 2.2S. I don't know anyone with the 'S' cams on a 2.7 that didn't like it. This is the same cam profile as the 'RS' engine...

-Wayne

[70SWT]

Thanks for the info, Wayne. I've purchased both of your books and will reread the relevant areas as my knowledge of these engines is nowhere near what it needs to be to start buying components. Regards Al