Originally Posted by
RWD fords rule 
Just read this, some key points:
Cast iron guides with the guide bosses removed will only last a very short time, bronze K-line guides are Bomb Proof in a competition engine, shortened cast iron guides are a Bad idea, the machinist may not know half as much as you think he does, what people say about machinists and what they really do can be an incredibly large gap! judge by the quality of machining you see first hand rather than word of mouth
YB rods will take 8000rpm in a 2.0 engine with light forged pistons quite reliably, but I would not trust them above this, the small end will pull clean off the top of the rod if given enough rpm's over a long time, NA YB engines have heavier pistons and failures have happened going to 8500rpm regularly, you might see 3 seasons life out of them or more, depends on how hard they are being revved
YB rods with a 1600 short stroke crank will be Bomb Proof with your light forged pistons, 8500rpm will be completely reliable, 9000rpm would be pushing it but they would live for a while even at those rpm's, the piston movement is much slower and less harsh around TDC with your effectively long rod short stroke combination, your rod ratio is 1.95 to 1, a YB rod in a 2.0 engine = 1.67 to 1, added to that the shorter stroke, greatly slows down the distance the piston has to travel per crank revolution greatly slowing down piston speed at any rpm, all of the above means you will have a super reliable combination
About pressing in new inlet ports, you would be better with 45.5 to 46mm inlet valves, this will allow you to make the ports a little larger and still have decent port velocity
You are correct that a 36mm parallel port will work very well for a full on 1600 engine, 35mm is also plenty, over 36mm will just throw away toque and engine response
I would gradually flare the ports larger after the head up to 45mm webers or 40mm TB's with dead straight port runners and TB's being ideal, with a small tumpet radius instead of a large flared entry like Jenverys which loose some usable power for "looks"
Place the new port as high up as possible under the rocker cover, leave a nice entry into the short turn, raise the short turn as much as possible to make best use out of the valve area as you said
The port bowl area should be made much larger than the 35 to 36mm diameter of the port, ideally the port would get a lot larger around the valve guide area to slow down the airflow and allow it to turn around the valve seat, as for the bowl area just under the valve seat, this should be 39mm if it is a 44.45mm valve or 40mm if it is a 45.5mm inlet, make this section parallel (not including the short turn) for around 10mm down from the top of the 45* valve seat, then make it considerably larger up to the valve guide and gradually going back to the port diameter
For valve seats, use all 1.6mm seats, a 35* x 1.6mm top cut, 45* x 1.6mm seat, 60* x 1.6mm lower cut, 75* cut over 3mm long, the 90* bored throat diameter will blend into the lower 75* angle, use 88% throat diameter for this engine, this shape will make the valve seat act as a Venturi increasing airflow, throats that are too large just under the valve seat loose airflow and velocity, 90% diameter is ok but over 90* is too large, 90% of 44.45mm = 40mm, this is the upper limit for the parallel 90* bore section with the valve size
The short turn will be blended into the port to create the best short turn radius by hand/experience
The 35* top cut is a little better than the usual 30* cut which does not match the pinto chambers as well as a 35* top cut, the 30* cut leaves a step that needs blending out, a small point but if you have a choice of cut angles go for the ones I listed, they are about as good as it gets imho, some people use narrower 45* seats but there is no advantage imho and a 1.6mm seat on a large valve is about as narrow as practical, even 1.8mm is fine, more than that is too wide
Be very careful with cam choice especially if you are using carbs in a 1700 engine, a 2.0 cam will be a few steps up in cam from the get go, overlap is to be avoided like the plague in an engine like this
The only cam I would recommend for this is RL31, forget anything else, it just won't work for you, if you want less cam choose BP285, but RL31 will give the best balance of torque and HP, you will be quite pleased with this cam for racing, for fast road BP285 is a good choice with lower overlap again
All of the usual big power 2.0 pinto cams will not be suitable due to very high overlap for a low cc engine, they would be real pigs below 5k
If you want every last hp you can get and don't need driveability below 5k and are using TB's then you could stretch to using a lumpier cam but it will want to live at 6 to 8k all the time, in that case BF63 would fit the bill along with one or two others
XFlows are too easy...
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. Don't you mean " someone built an 1800 " 
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