My expensive pointers.
1. Jack says its pointless to bolt an x-flow onto a 250, as its easier to go for the full Aussie engine. He's right.
2. Jacks method of bolting an x-flow to the US 200 is not that difficult, but the nature of the extra block width and ignition creates other issues which mean its not a bolt on mod.
3. The X-flow head will never, ever be a mearly bolt on mod. It requires a total strip down.
4. I advocate Jacks method, but I differ in that the 0.25 by 1.25 by 20.25" stiffner should be bolted to a 0.250-0.340 thick adaptor plate, drilled for the 14 head bolts, the US water galleries, and the six 3.68" pistons.
5. The stock US pistons should be used, which have a ring land to top of piston space of 0.250". The clincher here is to get a 0.250" longer rod. With the US 200, your stuck with getting the aftermarket 0.912" wrist pin Pinto 2.0 rod, on a 200 crank ground down to 2.047" pins, not 2.126". It improves the rod ratio ratio to 1.6:1.The specific power goes up half the improvement. A 7% improvement yields a blanket 3.5% hp and lb-ft increase every where.
6. On the US 250, either the complex mods to the 300 rod has to be used, and cut-down width wise and at the wrist boss, and then bushed from 0.975 to 0.912". The other option is the Aussie 200 rod, 6.27" tall, and getting the 2.5HSC piston, and shiming it up with a 340 thou deap spacer. The deaper the spacer, the less the risk of getting the top ring caught. At 5500 rpm, there is almost 20 thou of streatch in the rods, piston and crank. The rod ratio with the 300 or 250 rods is 1.59 to 1.60:1.
If you use any of the US ignition systems, there is not much room with a cross flow intake. Its dead easy to bolt and unbolt the manifold to service the bigger body US distributors, and the 340 thou spacer will raise the X-flow intake just enough to access a Duraspark I.
The best way to get the 250 to take an alloy head is to add a 250 thou spacer plate, seal the splayed pushrods with five individual 1/4" by 3" by 1/4" plates or one long 1/4" plate. This allows you to Allen bolt the 1/4" steel plate to the block topping plate. There is no need for welding if it is pined back after the head is torqued up. There is Devcon (JB Weld) or 2-pack epoxy mixes which form a great union if done right.
Follow religously what Jack did on his X-flow Locost, without welding, and then bolt on a thick plate to hold the steel strip. What you will end up is with Jack Collins X flow running with no leaks, a much better rod ratio, and there will be no issues with head studs, rods, pistons, or major block mods. The weight penalty is 13 to 18 pounds of steel, and a dozen Frenchtown Flyer custom 3/8 pushrods to make. The head is 58 pounds lighter, so you save 40 to 45 pounds without much effort. The cam, lifter, and coolant flow is no different to Jacks, and you just have to use an Araldite adhesive just like the turbo guys use to set the block plate in place.
Jacks got it all together with what he is doing. It just remains for the rest of us to catching up, and reduce the risks of leakage.
See the marks left form the rings? The park 275 thou below the deck on Ford 200's, and 375 thou on the 250 log. This is why you can use a stock piston with a longer rod. All thats needed is a 250 to 340 tall thick plate to allow the pushrod holes and longer rods to fit up neatly.
^The stock US 200 log block, showing the trim 5.625" width, with the true left (lower) side showing coolant holes, while the true right has none, and very little support. This is why the non-cross flow blocks are so much lighter.
^^The X-flow gasket, showing in excess of 0.3" of over hang at the lifter side of the block.
^^^The X-flow block, showing the immense 7" width, with the true right (upper) side showing coolant holes, while the true left, lifter side (bottom) is free of coolant holes.
^^^^The front pushrod hole needs some elogation. Note the by pass holes on the front of the gasket. These have to be plugged up on the log head block.
^^^^^The elongation of any of the splayed pushrod holes goes way beyound the confines of the log head gasket. Oh dear!
^^^^^^The log gasket on the X-flow block. Oil gallery differences are not a big issue. Jack uses the stock X-flow bolts, and a hollow pushrod and SBF lifter with oil holes.
^^^^^^^A graphical view of the width implications that have forced Jack to advocate the block adaptions, and blocking off the coolant flow to the exhast. Smart idea, as the x-flow block is simply 25% wider than the 200 Log head.
^^^^^^^^This is the log head I'm fitting to my formerly x-flow 250 six. There is no way the stock exhast will fit, and this is why the log head block is so trim. The exhast clashes with the super wide X-flow block. But I can fix it!
^^^^^^^^^This shows the over shoot with the x-flow block going crazy wide, with the log head is dwarfed.
^^^^^^^^^^One my 200 log block, the x-flow head needs an 8" distributor spacer, a 1.375" manifold spacer, and a 250 thou spacer to accomodate the head and 5" rods.
Regards,
Dino
