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How much do you think an engine rebuild on top end and bottom end would cost. (I have the full gasket set already). I also need to bore out the cylinders because there is more than 4 thou between pistion and cylinder.

Any estimates would be appreciated.
 

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It may not be the same motor but when I did a full rebuild on my 503 the costs were as follows:

1) Rebuilt Crankshaft: 312.95
2) 2 x 0.020 over pistons = 110.00
3) full Gasket set = 33.95
4) cylinders bored and honed = 120.00

All money is in Canadian dollars

I did all the work myself and now the motor is back together and running like a top
 

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That is very close to average fixed cost for engine overhaul with bored cylinders. and that is less the labour of engine disasembley and reasembley which can be any where from 4 to 8 hours depending how dirty the engine is and how clean you want it after. A total of $800.00 Cdn. parts and labour would be a good guess.
 

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1972 T said:
o really i was told 4 thou was the biggest clearance does anyone know for sure ???
[snapback]721870[/snapback]​
My 1982 shop manual list the clearance for the following engins.
247 .0026" - .008"
277 .0028 "- .008"
354 .0031" -.007"
377 .0028" - .008"
454 .004" - .008"
464 .0031" - .008"
503 .0028" - .008"
640 .0031" - .0086"

I don't have any info on the 440 model but the majority are at .008" max.

Check your compression and if its bad then you will have to do something about it.
 

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Attention 1972 TNT 775.........The engine you want to rebuild & bore jugs (?).
Are you talking about the engine you have on the 1972 TNT rebuild project that you have pics of in another thread that you are calling a `79 engine ??? If so......The engine on the 72 has a `74 or `75 crank shaft ( I can tell by the clutch), the fan shroud is a `75 shroud. If you have cylinders from a `74 to `76 ( & some `77) you can NOT bore the cylinders, they are chromed lined directly onto the aluminum
Piston to cylinder clearance for a `74 to `76 type 440 is .003 to .006". If it is a chrome lined jug & the chrome is still good, the clearance will be fine. If the chrome is done, your looking for a different jug. Yes you can get it re-chromed but you could buy two complete used engines for what that would cost.
 

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its not worth rebuilding it man with the money you spend on it im sure you could find another sled. Plus its risky working with boring and so forth. Not everyhting is gonan be exact you will need oversized pistons wich may have exessive clearence etc... All I kno if I have a sled I wouldnt even do the rings on it, its not good to put new parts on old parts.
 

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I would have to disagree withyou deagus. Boring is not risky. You buy the pistons and the cylinder is bored to match the new piston size with the new parts tolerances. If they are crome lined then they are not able to be bored. I have done 2 snomobles and one atv with no promlems at all.
 

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Agree with sleddoc. By the way you gave him the 440 specs. The type 454 is the 436.6 motor. I'm getting ready to doo another one myself with 50 over pistons which should give it about 454cc.
 

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Well I guess it aint tht risky, but there has been problems wen ppl bore there cylinderes theve had eccesive clearence and what not. But they probably bought the wronge pistons. The only time id say to rebuild a sled is if you do a complete job. Not just the rings. You are making the engine like new again. You are giving the sled high compression which will put more stress on the bearings and crank. But from what I see you are doing it looks like your doing a complete rebuild so thats good. I went to a shop and they reccomend doing a complete rebuild, that were I got my info from
 
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