Heat Exchangers Question (2 pictures)

[Adidas]

I've got an 83 3.0 911 with the later style thick flanged heat exchangers. Pictures below in first reply (picture1) Can an early 74 style thin flange heat exchanger mate up as well? The exhaust pipe on these units extends up above the top of the mating flange and actually seats inside the exhaust port of the head (picture2). Will a thin flange with a flat top seal properly? Any other options? Thanks.

[Adidas]

2 pictures here.

[James Brown]

For the most part, they will fit, bolt pattern same, but needs fitting parts like spacers and gaskets, and if early, oil lines are necessary. But why? Not much increase in performance if using small, old stock exchangers.

[m1franck]

Also, install shorter 8mm x 37mm threaded studs, plus new lock and barrel nuts. Here's the studs you will need:

Pelican Parts - Product Information: 999-062-006-02-M260

[sailchef]

Adidas,

you had another post earlier about "backdating" from an 83 system to a 74 system. I don't want to assume to much and don't want to insult anyone , but I need to ask....You do know that when you backdate a heating system in a 911 most people just switch out all the goodies up in the engine compartment and still use the existing exchangers? It would save you a lot of work.

Again I may be reading into this the wrong way. You may have another reason for doing this.

[James Brown]

And I know the SSI's are expensive but there is a difference. and, sadly, one of the only ways to go if you want heat.

[Adidas]

Thanks for the input everyone. Sailchief I certainly see now this option which will save alot of work and money. I appreciate it.