SSI / early 911 question

[SSL]

Am in market for stainless heat exchangers for my early '65 build 911. (Chassis # 301573/eng #901665). Have been told early models experienced recall due to CO problem, a heat exchanger modification was made, and if this mod was not performed on my particular 911, that a off the shelf SSI may not fit my application.
Have done search for SSI (Stainless Systems Inc??) to no avail--
Pelican SSI's start in '66 (and were the source fof the above info.)
(P/Products show no compatability issues ) Would rather resolve fitment questions prior to ordering. Thanks Steve

[Early_S_Man]

Steve,

Warnings about the dangers of CO in the passenger compartment due to corroded heat exchangers began in the early '80s. SSI's were the solution, then, according to Bruce Anderson ... and most would still concur, today!

The shenanigans pulled by the factory when the factory first fitted the 1967 911S heat exchangers to 'normal' 911 engines are still a bit comical!!! A pair of 1.5" restrictor ring gaskets were fitted between the HE's an the muffler ... otherwise owners would have benefitted from an increase in hp ... up to 140 DIN hp from the normal 131 hp of the 'log-type' heat exchanger engines! After revised cams became available to detune the normal engine back to 130 hp ... normal 2" diameter exhaust flange gaskets were used from the 911S engine. Delay in the availability of those revised cams was the reason for the restrictors in the first place.

[campbellcj]

I would call John Daniels @ SSI directly. (415) 883-2000

[SSL]

Warren thanks for the history. One question, why did Porsche restrict exhaust flow (via 1.5" rings)? Were they concerned with 9 more HP being delivered through the drivetrain, and consequent engineering design considerations, or was it an emissions question?

ChrisC, Thanks for the number--that's what I will do. (Did Google search & could not find).

[Early_S_Man]

Steve,

The whole reason for the restrictors was factory concern about criticism about the pricing/value of the 911S model ... if there was only 20 hp difference over a base model 911. Of course, the brakes, shocks (factory standard KONIs on 911S) and Fuchs wheels with VR-rated tires, and anti-roll bars were part of the $1000 premium that the 911S cost, so, IMHO the concern was bogus ... but marketeers are a strange breed!

[svandamme]

its like when intel was selling 300 Mhz processors as 233Mhz and restricting them in the chipcode and painting a different number on the package