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| coryu1 |
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Hi,
Im helping a mate build up a decent 250 from an xf for his cortina. The plan is: A four barrell 465 & manifold Exhaust (what size??) Compression up to 10:1 a cam like 146861,2 from crow cams, ie peak power round 5400. 224 duration at 0.050" Mild port/polish So what do these rev to stock? Whats the weak link in reving to ajust under 6000? How much will the stock heads flow? and can you shave the head enough to bring it up to 10:1. anything else? thanks Cory |
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| The Dog |
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Weak link on a 250 crossflow is rod bolts. Only thing I have ever seen have a catastrophic failure. (see pic below). The 465 is a good choice but be sure to runa proper redline manifold not an adaptor plate on a standard manifold. If you get a cam from crow cams match it with the valve train kit. Gets you valve springs, collets, retainers and I think a roller timing kit. We ran 1 14892 in a TE and that would embarress most HSV owners without raising a sweat. Be careful with compression. This can create more hassels than its worth.
Remeber balancing an engine is priceless and if you can afford it and wanna rev it roller rockers are a must!!!
_________________ You'll ride a black tornado across the western sky
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| Interceptor |
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the other weak link if you wanna rev it is the pushrods
_________________ Banned |
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| The Dog |
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forgot pic
_________________ You'll ride a black tornado across the western sky
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| coryu1 |
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thanks guys, that pic is pretty awesome.
So replace rod bolts with any high tensile bolt, or are there special/better ones? And pushrods replaced with....? or just leave them provided it isnt reved past 6? thanks again Cory |
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| Squirt |
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{USERNAME} wrote: And pushrods replaced with....? or just leave them provided it isnt reved past 6? If your going to the trouble of getting a crow cam,valve springs, retainers & collets you may aswell get a good set of push rods from crow aswell.
thanks again Cory As for reving it past 6000RPM ....................WHY DO YOU NEED TO 
These engines are a low rev high torque engine, anything over 6 is just a wast of fuel and engine life. If you set your cam up right you can have it start barking from 1100RPM's. The best piece of advice I can give you is when it's time to build the engine "GET YOURSELF A DEGREE WHEEL FOR SETTING UP THE CAM" this alone will make a significant difference in the performance
_________________ Knower of ALL......Master of NOTHING !!! |
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| The Dog |
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Everything he said above. Rod bolts from any reputable company will do the trick!
By the way the engine in the pic ran until the carb ran out of fuel cos the fuel pump was smashed off.
_________________ You'll ride a black tornado across the western sky
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