Ford 144-250 inline 6 high performance building
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You need to first determine what the final results are desired for the inline 6 engine build.
- Daily driver
- Mild performance
- Hot street use
- Race only
 Aftermarket support
These small Ford inline 6 cylinder engines have a small, limited selection of aftermarket parts, but there are parts from other Ford engines that fit them, and work better than the stock parts.
For example, if you want a flat top piston there is none available for a 200, but a 2.3L HSC ("High Swirl Combustion") Ford Tempo piston is a high swirl flat top piston with the same 3.680" bore size as the 200. The only difference is the 2.3L HSC pistons have a 0.090" pin offset, and the 200 pistons have a 0.060" offset. However, they still work fine, and are available oversize up to 0.080" from Speed Pro.
When working on the cylinder heads on the older engines (1960-'68) the 1960-'68 heads do not flow well. Replacement 1969-up heads are better, particularly casting numbers D8 and E0 heads, which would come in 1979-'83 model years. These heads have 1.75" intake/1.36" exhaust valve sizes. The exhaust valve seat can be machined to 1.5". The drawback to these heads is the chamber size is 62cc, 1960-'68 heads are 52cc, so compression drops approximately 1 point. There are also Australian cylinder heads with removable intake manifolds, but they are expensive. There was an aftermarket aluminum head developed from the Australian head available from classicinlines.com, but it is not currently available.
Originally, Ford used a steel shim head gasket that was 0.025" compressed, these are no longer available. What is available today are composite head gaskets that range from 0.045"-0.055" compressed, so the cylinder head must be machined at least 0.025" to make up the difference. If you use the larger 62cc chamber, the head will need to be planed down a bit more depending on the desired compression ratio. These heads can be milled 0.090" maximum.
Aftermarket cam grinds are available from Clay Smith, Comp Cams, Isky and Schneider. Be aware that some of the cams offered exceed the lift capability of stock valve springs, which is about 0.450". They also may exceed the lift rate at the maximum RPM. However, the good news is that there are a few aftermarket spring options.
Clay Smith offers a couple of options, but they may require machining the head for PC valve seals. Another option is Ford 302 intake springs, which will allow just over 0.500" lift and will provide sufficient pressure to prevent valve float at high RPM. These are single springs, which allow the use of stock valve seals. However, the valve retainers for these springs were designed for 11/32" diameter valve stems. In order to use them with 144-250ci valves, which have 5/16" diameter stems, it is necessary to mix the 302 V8 retainer parts and the 6 cylinder retainer parts.
Both of the 144-250ci and 302ci retainers have three components:
- The outer retainer which contacts the spring.
- The inner retainer which fits inside the outer retainer.
- The two (2) valve lock halves which lock the valve stem to the inner retainer.
To use the 302 intake valve springs, start with 12 stock 302 intake outer retainers. Then take 12 stock 144-250ci 5/16" inner retainers and place them in the 302 outer retainers. Finally, you use the 144-250ci valve locks on the valve stem. Now you have a 5/16" retainer to mate the 144-250ci valves to the 302 intake springs.
For induction, the factory single barrel carbs flow between 150-200 CFM, so a 2bbl really wakes them up. Holley 5200 2bbl's (a licensed version of the Weber 32/36 carb) work well. Several places online have carb adapters for them. Another approach is to have a machine shop mill off the 1V carb flange from the intake manifold, creating a flat surface on the intake manifold "log" to which a fabricated adapter plate can be mounted. The other advantage of using a Holley 5200 is that the readily available Weber 32/36 jets fit this carb. (Any 5200 you buy will most likely need to be re-jetted as it was probably intended for a 4 cylinder engine.) If you decide to go this route, buy one with an electric choke and an anti-dieseling solenoid ('86 Ford 2.3L, for example) and save yourself a lot of grief.
K&N makes a couple of air cleaners that are designed for this carb. The shorter one will definitely clear the hood, but the taller one may work if you keep the other clearances tight.
Holley 2300 2bbl carbs also work well, adapters are also available, but again, direct mounting to the intake manifold is the better option. A carb with about 500 CFM for a boosted/turbo application or about 350 CFM for a N/A application is desired.
Turbochargers have become popular for these engines; a smaller T4 will do nicely. A J-pipe up to the turbo from a factory manifold will work, and is simple to install. A Garrett GT28 inlet adapter flange (2-bolt style) has an integrated O-ring and, with very slight enlargement of the bolt holes, will bolt directly to the stock carb flange on the early "small log" head. This allows you to connect a turbo outlet directly to the manifold in a draw-thru setup. This flange can be found easily from many online vendors with a Google search.
Some of the basics for turbocharging are:
- Fuel pressure must rise on a 1:1 ratio with boost pressure with a blow through type carb.
- Carbs have to be modified by installing a nitrophyl float and removing the choke in most applications.
- Modifications to the fuel curve may be required.
For Ignition, one common upgrade is the Ford Duraspark II ignitions. This can be run with a factory Duraspark II ignition box, an MSD box (MSD makes a Duraspark-to-MSD connector for a clean installation), or even a GM 4-pin HEI module. The GM module needs to use some form of heat sink along with thermal heat transfer compound. When buying a Duraspark II distributor, get the single port vacuum advance model. A factory application for the Duraspark II single vac distributor would be a 1978-'80 Ford Fairmont w/a 200ci inline 6. There are more but they all have the same part number. A drawback to the Duraspark II is it will not fit the 144 nor the early 170ci inline 6 engines.
Another option is the GM style HEI distributor conversion for both the later 170ci and all 200ci engines. Take care to buy the correct part for your engine as the oil pump drives are different on the early 170ci and all 144ci and are not interchangeable with the later 170ci nor the 200ci. It has the benefit of easy installation (one fused power wire from the ignition switch, one optional tach signal wire), as well as readily available internal components, including timing curve kits, coils, caps/rotors/plug wires and ignition modules.
 Water pump
You may decide to only race your Ford inline 6 powered vehicle. The usual modifications for any race car will function the same on the inline 6. There may not be a direct bolt on kit, modifications may be needed.