Engine

Engine

The ford 200cid inline six is a much maligned engine in performance circles and, frankly, it's kind of a turkey.  Stock,  it only makes about 100hp, give or take 10, and is wheezing hard at 4200 rpm.  But, it also makes 190ft-lbs of torque which is pretty impressive (these are factory claims at the flywheel).  The big problem with this engine is the head with the integral intake manifold.  There are several solutions:  clever machining, replacement with an Australian or Argentine head with separate intake manifold, and now, (finally!) upgrading to an aftermarket aluminum head. Performance potentials for each option are roughly as follows:

A) Modified US log head: 145 hp and 160 ft-lbs at the wheels.  
B) Aussie or Argie head: Probably around 180 hp.
C) Classic Inlines Aluminum head:  Around 210 hp and 250 torques.  

Click this link for dyno data on various engine configurations.

 I went with option A for financial reasons.  There were also several versions of this head made.   This car had the small log, small valves variant.  There were a lot of other choke points on this engine besides the head, so I've focused my inital attentions on bolt-on modifications, but you can scroll down for an accounting of my head modifications.

Exhaust
 

All my engine projects begin with a header and this was no exception. I installed a dual outlet header from Cliffords and mated this to a 2-1/4" inch exhaust with a quiet turbo muffler.  Alone this was a worthwhile improvement that made the engine run better, stronger, and cooler.  Still, I knew such a vast engineering improvement over the stock manifold and exhaust should be producing more power.  Clearly the problem wasn't getting air out of the engine, it was getting it in.

Ignition
Next I installed a brand new Duraspark distributor and module for an '79 Fairmont along with an Accel high power coil and some new Bosch wires.  Then I advanced the timing up around 12 degrees initial or so.  This dramatically improved starting and also gave me a bit more power and smoothness, but still not enough.  The Accel coil died after only a couple of months (was I supposed to install a resistor?) so I replaced it with an MSD Blaster 2.

Intake
Eventually my single barrel Autolite 1101 started dying on me. Thank goodness!  I finally got motivated to install the Weber 38 two barrel that had been sitting on my shelf for three months.  It only took about three hours to install and calibrate.  I used a cheap adapter from Langdon's Stovebolt, which left the carb cocked at an angle, and bent the stock throttle lever to connect to the carb. THIS really woke up the engine.  Major improvements across the powerband.  The electric choke is nice, too

The Weber 38 DGAS is a synchronous two-barrel carburetor.  For performance I strongly recommend it over the 32/36 DGEV progressive.  The DGEV is an economy carb and while it offers an  improvement in performance over the stock carb, its potential is limited.  I've used it on three different cars and have always been dissapointed with the power. The DGEV will run better and make more power than an Autolite 1100 and it is less expensive and capable of better economy than the DGAS, so for a mild build it is appropriate.  Many worry that the DGAS will be too big for their 200s and will bog at low revs.  Nothing could be further from the truth.  The throttles on this carb are only 38mm, and the venturis are even smaller, so the intake velocity is actually quite high.  Off-idle performance is excellent, and it only gets better from there.  I ran this carb on a stock 110cid MGB and it worked great. 

Head Modifications
In my never ending quest for more performance I aquired an "M" casting head.  The intake port where the carb mounts is 1.75" as compared to my car's 1.5", and the volume of the log is greater, too. Presumably I could have bolted this head straight on and seen big performance gains.  Instead, I decided to port and polish and install hardened exhaust seats with larger valves, 1.5" exhaust and 1.75" intake.  I also had the stock carb mount milled off an a large oval hole and adapter plate made to mount the Weber directly to it.  The head was be milled for a  chamber size of 51.5cc.  My other head had 56cc chambers, so that boosted my compression from around 8:1 up to about 8.8:1.    Finally, I installed the head with 1.65:1 full-roller rocker arms.  This modification really maximized the performance of this otherwise stock engine.  

I cleaned up the valve pockets and chambers...

...and did a ton of work on the exhaust ports

When I got my head back from the machine shop it was looking pretty awesome.

Here is old carb mount next to the new to give you an idea of where I started from. You can see the larger port and the difference in volume of the manifold

And here is a side view of the adapter. Notice it has the same 4* inclination as the stock carb mount.

This is the phenolic plastic spacer designed to improve the vacuum signal at low revs and keep the carb insulated against heat.

These rockers are just too cool.

The 1.65 ratio really helped since I was using the stock cam at that time.

Linkages are often a hassle on carb swaps, but this one was just easy.  Modeled on the stock unit using a piece of brass rod. Very simple yet effective.  I'll upgrade to steel with spherical bearings later.










Chamber is 51.2cc. That's down from about 56cc on my old head. Valves are 1.75 & 1.5 "swirl port" or whatever they're called. They have a back-cut looking profile with tapered stems.  I suppose I could have polished the cambers even more, but this is waaaay better than stock, which was rough and full of protrusions.  I also clearance the chamber walls around the valves, and good thing, too, since it's such a tight fit.

Old intake valve versus new

You can see that the stem is narrower on the new one.

Since car had been sitting for two weeks waiting for parts to show up, I decided to install this fan I'd had for a while.

Poor baby wants to go vroom...

When I finally got it back together and reasonably tuned I took it out and was well pleased. It felt a wee bit peppier from idle to about 2,500 rpm, then pulled strongly until about 3,500 rpm, where it really took off to about 4,700. This was a significan't contrast from before, when the power would actually begin decline around 3,500 until it just fell flat at 4,200 and wouldn't rev at all past 4,500. Sounded much meaner, too.  For anyone wanting to improve an otherwise stock Ford 200, headwork is the place to start.