Proper exhaust stud length for 3.0L SSI backdating
 

Hello All-

I haven't been able to locate a post detailing the proper length of exhaust studs and oil lines necessary to install a set of 1973 version SSI heat exchangers on a 1981 3.0L engine. Just preparing to do the backdating once the heads return from the machine shop.

A part numbers or any information would be greatly appreciated.

Thanks,

--Kevin

Half way there...

Oil line info:

• 911-107-739-10-M20 - One (1) needed
And either:
• 911-107-729-10-M20 - For cars WITH a Front Oil Cooler
OR
• 911-107-728-00-M20 - For cars WITHOUT a Front Oil Cooler

My stud lengths are 35 mm as installed by Ollies for my 3.0 backdated engine w/ thick flange SSI.

Thanks for the reply...I'm getting a handle on this slowly...

In this case I have a set of SSIs from a 1973.5 911T to transplant onto a 1981 911SC 3.0L. As far as I can tell the proper SSI product for the 3.0L engine is made with THICK flanges. The 1973.5 version is a thin flange model.

Has anyone used the thin flange model on a standard 3.0L (non-R.o.W. engine)? The heads are at the machine shop being reconditioned...so I'm not able to do a trial fit.

Is it possible to use the thin flange SSIs with the 3.0L engine and if so, are different exhaust studs required?

Thanks again to all that read or read/reply.

I just put the thin flange SSI's on my 78SC. I think that since you have your heads off being redone, use 35 (or 37mm as pelican was out of 35's) and all should work out fine (hmmm...just thought though that the exhaust port changed sizes from 73 to 78 (and 81) so I don't know that this will work after all.

With thin flange the stud should protrude about 20mm......