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77xcfalcon

Is my crossflow block worth using

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Hi all. I am rebuilding a xc falcon. The engine was rebuilt by the previous owner and has only done about 5000 kms since. After tearing it down I could still see hone marks in the cylinders and all seals bearings etc still looked barely worn in.it had a aftermarket standard cam standard crank and rods and aprox 28 cc dish pistons.I would like to use the original block but I just took some measurements and the cylinders measure around 94.4. Does this mean it has already been bored out 40 thousands of an inch? And would I be better of starting with an new block. It will not be a super high power engine, plans are midrange cam, standard crank and rods, c1 alloy head with standard valves and bigger springs,efi with aftermarket ecu(probably mega squirt if I dont pick up anything else in the mean time) 6 3 1 extractors and 2.5 inch exhaust, msd 6 al ignition. I have most of the combo already just got to get cam, new pistons and ecu. Thanks guys

 

 

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Just wasn’t 100% sure about the history of the car. Wanted to check it all out to be sure, plus it had been sitting for a while. And I want to bump up the compression a bit as well. I thought the best way would be to replace the massive dish pistons that were in it. It had a iron head that I’m replacing as with a alloy. And I’m painting the car so it was coming out anyway.


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Piston choice is pretty limited with these motors as there were no crossys in the USA market.

Upping the comp is best done by decking the block, as this requires the least amount of material removed for a given increase in ratio.

To zero-deck, you should get your pistons first, install without rings, bring each one to TDC and check your deck clearance. The biggest clearance is the amount to be shaved. All other pistons will need skimming down to that height if they differ by more than a couple of thou.

Everything else should be fine if it was a good runner before but just check the bearing shells for even wear, etc. A very light hone will be needed to bed the new rings. Dunno how high you want to rev it but a balance makes a big difference on a long-stroke motor.

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I'm with Greg. Zero deck with those pistons and a c2 head would yield very nice compression.  I've taken big hp and torque blocks to .060 and I know others have taken them further so be guided by that. 

Balance is pretty much a must if you want reliable trouble free running on these old girls. Factory tolerance on these things was very wide. 

Id be using that engine as a base for sure, especially if it's fresh. They generally have anything from .045-.050 deck height so giving them a mow, even with the dish pistons, nets good comp. add in a c2 with .040 off it and your in good comp territory if it's .040 over 

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The part number on the pistons generally tell you if it’s oversize. Nothing wrong with over sizing as long as it’s not overboard

Talked to a mate and he told me if I can’t find a oversized stamp on the piston then I measured it wrong. He was right both ways as I cleaned up the top of the pistons and found a 030 stamp on the top.


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Yup as above and give the ironhead to ando so he can flow test it for shits n giggles!!! Coz ironhead is missing from the flowbench section lol

Yeah it’s funny that there is no info readily available for the iron head. I’ve been looking to find the chamber size with no luck


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