Sneaky Sleeper /6 Build

This is just MY opinion, so take it as it's written; just an old man's opinion....

My personal car is a 1972 Valiant 4-door sedan with a flat hood, no body modifications and came from Momma Mopar as a 318 2bbl car.

I added a 360 Magnum (from a low-mileage Durango), a 4bbl carb, a mild Hughes cam, 340 exhaust manifolds, dual exhausts, an 8.75" rear, some 8-inch slicks and it ran 13.35 @ 102 mph on a 95 degree day at sea-level.

Not satisfied, (you're not the only one who can't leave well-enough, alone) I traded the 340 manifolds for a set of tti step headers, the piss-poor low-rise, MP 180-degree manifold for a Chinese rip-off of an Edelbrock Air Gap intake, and replaced the 3310 Holley with a Carb Shop modified 750 double pumper set up for blow-thru supercharging. I bought a brand new Vortech S-trim, V-1 centrifugal blower off ebay for $1,000.00. Had to build my own blower mount, and by the time I had a half-inch fuel system and an MSD Boostmaster onboard (along with a Snow Performance BoostCooler water/meth injector,) I was wishing I had a rich uncle who liked Hot Rodding.

But, the car picked up about 16 mph and ran approximately 1.8 seconds quicker (will go 11.50s, or so) with the new parts. Still idles at 475 rpm and makes 12 inches of vacuum for the power brakes, but pump gas would be instant death for this motor (still has the stock pistons and head gaskets.) It makes 445 rwhp on the dyno on av gas. That's up from 260 without the blower.

After I spent all that money and ended up with only a mid-11 second car (albeit with great driveability), I became aware of some slant 6 cars that made my car look like do-do.

Here's what I learned:

Because slant sixes were ORIGINALLY intended to be aluminum blocks, they were designed with overly thick everything... but the aluminum engines had so many problems, that Mopar abandoned the aluminum construction early-on, and simply poured cast iron in its place, without changing anything... so, what you have is a super strong engine in terms of construction, where it counts.

For example, the deck surface where the head bolts I am told, is approx. a half-inch thick. The head suface is equally robust, and the cylinder walls are so thick, they can be bored .100"!

Though there are only 4 main bearings, they are aproximately the size of the bearings in a 440.

Forged rods and pistons are available from Wiseco and their sister company, K-1 (and other sources.)

There's only one downside to this engine, as I see it: The head was designed for 170, and the ports and valves are not really suitable for a 225. There are some strong running normally aspirated Valiants and Darts out there, but they are rare.

My opinion??? This engine was born to use some sort of forced induction for two reasons: #1... It is very difficult to build a lot of horsepower in a 225 with the asthmatic head we are forced to use. #2 The basic engine is so strong, you can boost it to levels that would give a Buick GN engine all sorts of trouble, make excessive horsepower, and have an engine that will live.

Check out the turbcharged slant sixes on You Tube... low 11's and high 10s are not unusual.

You can't, of course, build a cheap slant six, and slap a turbo on it and go that fast, but I have read about nearly stock slant sixes that had a minimum of mods to the engine, running low 12's, with a turbo...

Look what I had to do to my 360 to get it to run in that neighborhood...

So, I'm building a slant six powered car, with a turbo. I guarantee it will beat the pants off my Vortech blown 360 car. My partner and I HOPE this thing will run 11 flat, or better. Talk's cheap, though; we'll see!!! :)

I guess my advice to you is to build a cheap tubo slant six with probably only ten or twelve pounds of boost, and it likely live forever and run in the high 12's....:cheers:

Here are some pix of this stuff...

Like I said, this is only my opinion.... yer mileage may vary...

Bill, in Conway, AR