WTB: 2.7 MFI heads

[Robert5995]

Hi, All -

I am hoping someone has a set of these laying around gathering dust. I *think* these have 16/40 valves and 36/36 ports, I don't want CIS heads. Please correct me if this is incorrect. Let me know what you have, thanks!

- Rob

[raspy2point2]

I think all 2.7 heads are CIS as the factory went to CIS starting with the 731/2 CIS 911T. 2.7 cars are 1974 to 1977 all are CIS. The only exception would be the 1974,75,76 Euro Carrera which is 2.7 with MFI but those are vary rare in the USA. So Europe would most likely be your source. Chris

[raspy2point2]

by the way-- these are 46/40 valves but I think the ports are 35/35 on the CIS heads; not sure on the Euro 2.7 heads. Chris

[tom1394racing]

Hi Rob

The attached chart should help you to understand what you need. Any 2.4 MFI head can be easily converted to 2.7 RS spec by porting and chamfering. I have 2.4 MFI heads should you need them

[raspy2point2]

I believe if you wanted to use CIS 2.7 heads with Weber carbs,you will be able to do that. Of course you will want MFI heads for your MFI injectors to fit. Chris

[Robert5995]

Hi, Tom -
Thank you for the wonderful chart. If, indeed, I can use an 80mm head (2.4S MFIs) on a 90mm cylinder without undue inefficiency, that does open up the possibilities. I have printed out your chart, and will do some research with my local expert here.

Raspy Chris -
Thanks for your input. It appears that the heads I am looking for are the RS MFI heads, made in '73, of course, but also later years (I think '74-76) on Euro MFI Carreras. If Tom is correct, then I should also be looking for '70-'73 MFI 2.4S heads with 46/40 valving, and 36/35 ports, P/N 911.104.008.00. That opens things up a bit!

Anyone have any heads with that P/N?

- Rob

[tom1394racing]

Rob

There is a slight chamfer cut around the perimeter of the combustion chamber on the 2.7 heads to accommodate the increase in bore from 84 mm on the 2.2/2.4 to 90 mm on the 2.7.

That chamfer cut and porting the intakes & exhaust on a 2.2/2.4 MFI head will make you a 2.7 RS head.

[Robert5995]

Tom -

You are a fountain of wisdom, thanks! What you are saying that my favorite air-cooled machine shop can make any 2.2/2.4 head into a 2.7 MFI head? Or, are you saying that the shop can make any 2.2/2.4S head into a 2.7 MFI head? Which would you do?

- Rob

[tom1394racing]

They should be able to make any 2.2/2.4 MFI head (T, S or early 2.4T) into an2.7 RS spec head.

[gled49]

FYI, original 73RS heads didn't have the later chamfer in the CC.