Just scored a Super Six and matching trans

At the very real risk of being branded a wild-eyed fanatic with an axe to grind, I'm going to jump in here, and run my mouth (er, keyboard) for a bit and play the devil's advocate and beat the drum for something I thoroughly believe in: forced induction.

The reason I believe in forced induction as regards the almighty /6 is this:

The slant six was originally a 170 cubic inch motor, and had a cylinder head that reflected the breathing capabilities of an engine that size. When the engine was increased to 225 cubic inches, the powers that be/were didn't make any effort to increase the valve or port size in the cylinder head, which resulted in a mediocre, at best, cylinder-filling capability for the 225 (and,later, the one-ninety-eight motor(s).) The engine was a grocery-getter with no aspirations toward high-performance; after all,they had 340s and even 440's for the Testosterone set. There was a weak-kneed (try and find one) offering that put the Hyper Pack manifold,cam, and a few other parts on the 225, but VERY few ever saw the light of day,and the /6 remained a poor-breathing, station wagon motor throughout its life.

That's not to say that a normally-aspirated /6 cannot be made to perform in a spirited manner if enough money is spent for a big valve, ported head, high compression pistons, a more efficient intake manifold (lots of choices, here) sufficient carburetion, and all the other speed "tricks" that racers utilize to increase the breathing capability of high-performance engines. There ARE some impressive /6-powered cars out there.

But, no matter how they tweak these unblown engines, the small ports and smallish valves (even the bigger, aftermarket ones) make it a real uphill battle to get enough airflow through that head for specific output much over the 1.2 horsepower per cubic inch range. And, to get into that territory, you need an engine that is so radical that it's not very driveable on a daily basis.

How to deal with this problem?

One possibility is forced induction.

A slant six engine has an unbelieveably strong "constitution."

Forced induction requires an engine that is robust, has lots of strength in the reciprocating assembly, and basically, is built more like a Diesel, than a gasoline engine. Those engines are hard to find... Thinwall castings, cast iron cranks and that sort of thinking at the corporate level has given us a recent history of basically "flimsy" engines that won't live very long under boost.

Because the /6 was originally going to be produced as an Aluminum engine,and Aluminum is not as strong as cast iron (dimensionally,) the /6 block and heads were created with those factors in mind, and when the Aluminum idea didn't work out for Ma Mopar, the cast iron /6 was born with a lot of the "heavy-duty" characteristics that were designed into the Aluminum motor, including a forged steel crankshaft.

The fact that there are only 4 main bearings is offset by Ma having made them virtually the same size as the 426 Hemi bearings, so the bottom end is incredibly strong, too.

Unusually thick cylinder walls, and a really thick deck and cylinder head deck contribute to a REALLY stiff package; the cylinder head weighs 84 pounds...

The bottom line is this: A /6engine is a REALLY GOOD candidate for forced induction because it can swallow boost without damage to the basic structure of the engine, and produce horsepower and torque in prodigious amounts, in SPITE of the basically "too small" ports and valves that were designed into that 170 cylinder head.

My experience so far, is very limited but I read a lot on the /6 Forum and this Forum as well, and from what I have learned watching others, it seems to me that a racer wanting to increase the performance of a/6 would do well to consider the factors I have mentioned before he/she builds a high performace car around a /6.

One thing about forced induction; there are several types available, and they all have different attributes. But having said that, I would like to point out that they ALL make an end-run around the limitations posed by that 170 head.

Just my 2-cents....