Some more information....
General
This engine swap is actually very easy to do. I used a 1970 Cadillac Eldorado 500 cid engine and TurboHydramatic 425 transaxle. The assembly is just as Cadillac designed it. After removing the Porsche engine & transaxle it was a simple matter of building motor mounts, CV joint adaptors and axles, a custom radiator and exhaust system. The Cadillac system has a single front and dual rear mount setup that was easily adaptable to the stock Porsche mounts.
Fitting the package in
The Porsche shock tower crossmember and sheetmetal behind the rear seat had to be removed. I chose a Targa body because of the extra unibody rigidty provided to help when this sheetmetal was removed. The body is still surprisingly stiff. When I was building the car onlookers swore that the back window would pop out and the chassis would twist. But it is all still nice and stiff.
When the final drive & axles arealigned properly with the rear wheels the powerplant is located perfectly fore/aft.....almost like Dr. P and Cadillac had planned for this swap to happen. The engine fits low in the back seat area as can be seen in the photos.
The Engine
The engine is a 1970 Cadillac 500 cid block specially build by Maximum Torque Specialties of Wisconson. This is THE performance Cadillac engine builder. The engine has been slightly bored, decked, and fully balanced. Forged rods and pistons are used, the very expensive Bulldog aluminum heads, pretty healthy cam with roller rockers and specially designed valve train. Roller timing gear & chain, high flow oil pump, and lots of other goodies went into building this engine. It pulled 517 +/- hp on the dyno. It idles a little rough and gives this Porsche a very suspicious sound! To keep engine area temperatures low we ceramic costed the exhaust manifolds in and out to direct exhaust gas heat out the tailpipe. We used the stock manifolds to keep it quieter under the luggage (since the engine is literally right behind you). A high torque starter, remote oil filter, Holley spread-bore double pump carb, and lots of custom billet stuff was also installed.
When you pull that luggage off and your onlookers see those "Porsche 8.2 Litre" valve covers you'll grin with delight at their complete bewilderment.
Powerplant Installation
After removing the shock tower and rear seat sheetmetal the engine just lifts up from below. I use the stock corner engine mounts in the back with different biscuits. The front mount was CAREFULY welded to the tosion bar tube.
Exhaust
I have had three exhaust systems and have settled on a MagnaFlow dual in, duul out muffler mounted in the typical Porshe location. 2.5" pipes are used. There is NO "humming" effect (Flowmasters sounded the worst). Certainly headers were considered BUT because the engine is so close to the interior I think the noise would be unpleasant. Besides....the power and torque is pretty insane anyway and I like the "sleeper" design.
Cooling
Engine cooling is handled by a specially constucted aluminum dual cross flow radiator. This radiator also contains the transmission cooler and uses two VERY high capacity fans. A high capacity water pump was also used. Several months ago there were some concerns with cooling as the car was getting hot. After installation of a large oil cooler up front with an electric fan activated with the radiator fan the car is staying cool at all times in stop and go and light freeway driving here in Southern California in75 to 90 degree weather...
