Head studs on 2.4 mag case

[hightuned]

Thanks for all the input, ive made up my mind and stick ill the superchager on a shelf for the future. Im sure a upgraded 2,7 can keep me entertained for the near future. Just a one more follow up question and ill leave you guys alone. 9,5 or 10,5 JE's? Ive read somewhere that 9,5 is all the comp ratio you should run on a single plug, does a upgraded ignition like msd help or is the problem only in the combustion chamers flame pattern so multi/more powerful spark wont help? And what cams should i use, was thinking S but Wayne recomends a 964 cam for a upgraded 2,7 CIS build, stupid question but doesnt can 964 cams with 4 bearing surfaces be used in the early engine or does he mean regrinding the early cams to 964 progile?

[Walt Fricke]

I wouldn't want 10.5 without twin plugging, for the reasons you suspect. MSD isn't going to have any effect on flame spread - one plug is one plug is one source of ignition only, and it will have a big hump to travel over.

You'd either need to get a reground 3 journal cam, or switch cam carriers - the 4 journal ones will fit just like the 3s you have.

CIS doesn't like overlap, which is why you have to keep the cams pretty tame.

Now if you were to switch to carburetors, or EFI - now you are talking. S cams would work great. But that calls for getting rid of all of your intake and starting over.

[hightuned]

Originally Posted by Walt Fricke

I wouldn't want 10.5 without twin plugging, for the reasons you suspect. MSD isn't going to have any effect on flame spread - one plug is one plug is one source of ignition only, and it will have a big hump to travel over.

You'd either need to get a reground 3 journal cam, or switch cam carriers - the 4 journal ones will fit just like the 3s you have.

CIS doesn't like overlap, which is why you have to keep the cams pretty tame.

Now if you were to switch to carburetors, or EFI - now you are talking. S cams would work great. But that calls for getting rid of all of your intake and starting over.

Tanks again, i hade do idea the carriers where interchangable. A small lobe separation angel makes sence as i understand it the CIS only measures fuel buy intake vacum? I have the E-cams listed at 102 deg LSA, and the S-cams at 97 deg but cant find the LSA for the 964-cams?

[Raceboy]

Pat williams has turbocharged a mag case'd 911 T: Pat Williams Racing (porsche)- Pat Williams Racing (porsche)- 1973.5 911 T(urbo)

And hightuned's fellow Swede (DPHANS) also with great results: 2.7 turbo?

[hightuned]

I have no doubt that the 2,7 would work great with a supercharger on E85, just had no idea they where so fragile. Ofc i would have chosen another engine if i was to buy one for the purpose of superchaging but as i alread had the engine and was going to rebuild anyway so i though it was a easy way to get some power in the old girl. Im going to drive it next summer and if not happy with it sell the drivetrain and build a new one based on a 3,2 or 3,6. Working on a Porsche drivetrain is pure mechanical pleasure and almost as fun a driving them.