Heat exchanger recommendation

Porsche-O-Phile · Porsche-O-Phile's Garage

Car is a '74 with 2.7, currently with stock "crossover" heat exchangers that pipes the passenger's side bank of cylinders across the front of the engine and hooks it up with the driver's side bank, then to a premuffler to the main muffler as a typical "1-in-1-out" configuration. What I want to do is run megaphones (insert diabolical evil grin here) but I would prefer to retain the heater functionality and not simply install headers.

So my question is: is there a set of heat exchangers that will allow me to run this sort of setup (eliminating the crossover and running each bank of cylinders straight back) so I can connect up a megaphone setup to it? Sorry if this is an ignorant question, but I'm running into diminishing returns trying to research it.

I'm assuming I could (optionally) run a 2-in-1-out muffler in lieu of megaphones with this setup too, right?

tobluforu · tobluforu's Garage

Ssi

Porsche-O-Phile · Porsche-O-Phile's Garage

Which ones? Should I just call them up and explain what I want to do d'ya think?

I like them, but they're also quite expensive. If there's no other way I suppose...

JP911 · JP911's Garage

A cheaper option would be to locate a good used set of early heat exchangers (pre-75). The 74 2.7 originally had the early heat exchangers that the SSIs were modeled after. Sounds like a previous owner decided to downgrade your exhaust setup.

mickey356 · 04-06-2010, 08:55 AM

John at SSI is a great guy. I spoke with him a few times and he was very helpful in my decision making.
Yes, you can run a 2 in 1 out or megaphones off SSI's.
I was looking to use a set of thin flange on my car (I was looking to modify them as my car needed thick) and called John to discuss it. The reality is you're still gonna pay a good amount for a decent set of used headers with heat capability so why not just save a little more and get exactly what you need brand new? The difference is probably 25% and John can ship MUCH cheaper than it would cost someone to ship across country. You'd have to find a good set and close to you to make it worth it. I'm just sayin

Ray_G · Ray_G's Garage

I did what JP911 said on my 76, which had the same exhaust system you currently have installed. I got factory 74 style early HE's. I will say that my car has the impact bumpers still, and the 2 in one out muffler for the impact bumper cars is a bit hard to find. The exhaust pipe is angled down more than the non impact bumper cars. (the impact bumpers are so big that it has to go lower to clear the valance) I wound up buying a later muffler, cutting the tail pipe off and "adjusting it" and then welded it back on. You can't tell by looking from the back, but it took some work to get it to clear everything. Also, if for some reason they PO put the later style oil lines on you will need to change them too...The earlier type are the rounded type that goes just under the trans bellhousing. and there is a different soft line for that as well.

Porsche-O-Phile · Porsche-O-Phile's Garage

Thanks guys - yeah a lot of stupid things have been done to this car over the years. I'm pretty sure someone scavenged the (desirable) early heat exchangers at some point and stuck me with the crap that's on there. No biggie - it's a project car and I was probably going to eventually look at SSIs anyway, but even so it'd be nice to have the early HEs.

Do the early (pre-73.5) heat exchangers both have the outlets facing rearwards (i.e. for a 2-in setup or megaphones)? Sorry for the ignorant question (I think the answer is "yes" based on the above), but the pictures/photos I've been seeing of people selling these on ebay and elsewhere all look like they're set up for the crossover 1-in setup similar to what I have now. Maybe that's why I'm getting confused - LOL! Are people deliberately trying to rip me off?

I'll probably call SSI. Good to know. I have a few other pieces to take care of first, but it's on my list...

Ray_G · Ray_G's Garage

this is the type you need:
FS: Early 911 Heat Exchangers
they have two outlets to the muffler. The stock muffler was 2 in 1 outlet.

Porsche-O-Phile · Porsche-O-Phile's Garage

They look decent in those pictures - are the flanges and bottoms okay also?

I might go that route. The appeal of nice, sexy shiny SSIs is enticing, but this might be a very good, common-sense, practical way to go... Lemmee think about it and do some more poking around. I still have several other not-so-cheap items to get for this car.

Ray_G · Ray_G's Garage

They are not mine, I just was showing you some that were for sale that were the type we are talking about. They look decent, and you could have them coated if you wanted. I bought some used ones and I had trouble with the flanges going to the muffler on mine. I had to weld them up and then file them flat again. They were not flat at the mating surfaces. I would bet that is common though.

IROC · IROC's Garage

One thing about megaphones on SSIs - they will stick waaay out the back of the car. Megaphones were designed for use with racing headers which typically have their mounting flanges 6-8" (?) farther in from the rear of the car. This flange position works great for megaphones (or my personal favorite Supertrapps) but they require "street adapters" for typical 2-in street mufflers.