Carburerated 2.7S Engine

[Rexs-911T]

Newbee to the site and just purchased a 1971 911T with a 2.4 Carburerated engine. Set up for racing and I am looking for a more street friendly setup. Plan on picking up a 2.7S that originally was set up with the typical CIS.

Can anyone recommend using the carbs off the 2.4 in lieu of the CIS. Will I have any issues doing this? The 2.7 I'm looking at does not currently have any carbs, CIS, MFI or anything and I will need to get it outfitted with a fuel system. Looking for some advise.

[haycait911]

this one can go round and round, but. here's my $.02.

the carbs will work on the 2.7, but not great without internal mods. power will be maybe a nick better than CIS and your fuel economy really goes out the window compared to CIS.

I'd sell the 2.4 complete as is, that way the purchaser can drive and do a PPI much easier. then buy yourself a problematic 2.7CIS.......OR........ buy a bulletproof 3.0 CIS engine. lots of cheap fun, dependable, decent fuel economy, and with an exhaust backdate a strong runner.

if you're set on the 2.7 you're looking at, better to buy a good CIS from someone converting, than use your carbs. do a VERY cafeful PPI on any 2.7. if it's not currently running consider it a core.

FWIW.

[haycait911]

additional note. as a newbie it's expected to post some pics and details. always fun to see someone's new toy.

[Rexs-911T]

Thanks Haycait, what kind of internal changes are you talking about, anything major. Possibly having someone else re-build the 2.7 for me and truse he knows the changes necessary but would like to know before I pull the trigger on it.

Have to figure how to post a picture still. Thanks for any advice.

[al lkosmal]

Rex,
The 2.7 is a great engine and very responsive to mods. The best street version that I have built was configured, as follows:

Both internal and external mods:

1. 9.5:1 JE pistons
2. E-Cams
3. SSI headers
4. 2 in - 2 out Dansk
5. Weber 40 IDA carbs

That being said..................I've configured 2.7's with only the carb and SSI/muffler upgrades.
Not a huge power boost, but the improvement in throttle response, etc will register on the butt dyno and they are a hoot to drive in that state of tune too. (your wallet will suffer over a well tuned CIS engine at the pumps......but not over your 2.4 racing motor.)

Or as Don suggests, get a good 3.0..................or head even further down the slippery slope .................I now have a 3.2 in my 73.....and a 3.6 on the stand............you get hooked on the low end grunt.

[JmuRiz]

That's good info to know. I also have a 2.7S on the stand with the stock CIS, and a set of 40IDAs on the workbench.
As much as I think it'd be fun to slap the carbs on and go (with my headers...in a 914)...I keep thinking that maybe I should hold out for a 3.2 and sell off my current stuff.

edit: Did you have to re-curve the distributor to get the full benefit of just adding carbs/headers(or SSI) to the 2.7S motor?

[JohnJL]

I have 2 complete CIS systems available.

I went to carbs on one and EFI on the other.

Nothing wrong with the CIS.

[JohnJL]

And a complete 2.7 motor complete and running available too. With warranty.

[chiroracer]

I think the internal stuff you'd want would be cams and pistons,the cis pistons and cams were very mild to work with the CIS.