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I have ID.d my 260 and have got the siezed pistons out. I can salvage it with a 30 over bore job, as it is the original motor. The heads are pretty rusted up will 289- 302 heads bolt on to the old 260?? Will the stock push rods fit and is there any hidden problems swithching to the newer heads. Not looking for a performance motor, just as stock and as original as I can keep it.
Thanks Ron
There are a few considerations here. The 260 has a bore of 3.80" as compared to the 289/302's 4.00" bore. The 260 heads had 54.5cc combustion chamber giving a compression ratio of 8.7:1, with 1.59/1.39 valves on the '62 heads and 1.67/1.45 valves on the '63-'64 heads.
What this means is that you need to stay with heads with the smaller combustion chambers or you'll lose compression, and if you go too big with the valves they will hit the sides of the cylinder bore. You need to look for early 289 heads, up to '66 1/2 would be best for a direct fit with the parts you have. No performance increase there though, they have the same specs as the 260 heads. Look at the casting number chart here for specific casting numbers on heads to look for.
Thanks TigerDan
This is my wifes project so I am new to older Fords. Performance is not a high priority. Glad you mentioned the valve to bore size as I have accesse to a set of early 302 2 barrell motors and was going to use those heads for now. There is a small chance the original heads may be saved but they are pretty rusty.
That may be a way to go.. Seems 30 over pistons for 260's are a bit scarse. No over heating problems?? Im sure if I live long enough I will have a lot of info on these little 260's.. I remember my bud had one way back when!!
Thanks
Not possible. You would have to bore it about 1/4" or whatever. If you bore a 302 over .030", you only gain 4 inches. That's how they make a 306 bullet engine. A 350 Chevy bored ,040" is about a 357. That 260 bored .060" would be a little less then 268 cubic inches.
These blocks are what's called a "Thinwall Casting". The maximum recommended overbore is about .040", any more than that and you risk making them so thin that they will run hot, not to mention boring through the side of the cylinder wall in extreme cases.
When these blocks are made they devolop a certain amount of core shift in the manufacturing process, meaning theat the cylinder bore isn't always perfectly centered in the casting. You can come across blocks that have them well centered but about the only way to tell is to have them sonically checked. One of thes blocks may take a larger than normal overbore but again, the cylinder walls will be so thin that it will run hot.
My Tiger was originally built with the 260, but when I got it it had a 302 already in place. I put a 289 in it but built a new 302 that's just about ready to put back in. Originality? Not me!
Last edited by TigerDan; Dec 14, 2005 at 09:19 PM.
TigerDan's advice is excellent; get some early 289 heads. The later heads used rail rockers, different pushrods and different valves. Up to 1966 or 67 is compatible IIRC.
If you don't mind some friendly advice, get hypereutectic pistons, and zero-deck them. You'll be glad you did.
Be sure to use some GM EOS or STP Oil Treatment in the motor oil to help preserve the cam. They took the high pressure lubricant out of motor oil and our older engines need it.
I build multi-dozens of engines a year. I have never had a cam failure. I use a good cam install lube, such as what comes from Crane cams during every install. Make sure you have timing and everything else close, so the engine fires up right away. Extended engine cranking to start a new engine is bad for the camshaft. Always pre lube by using an old distributor shaft, or buy the tool made for the job. Once the engine fires, run it steady at no less the 1500 and no more then 2000 RPM's for at least 20 minutes to break in the new cam. I then shut the engine down, change the oil and filter, and do the same process all over again. Then I run the engine again, making sure I vary the speed to help break in the rings. After 10 hours or so of this type of running, the oil and filter get changed, and the engine gets run to the regualr oil change interval. After that, synthetic oil can be used. Either I'm lucky or I'm doing something right. Like I said. ZERO camshaft, or any OTHER type of engine failure during break in.
dont tell me you cant bore a 260 to 289.i may have been lucky as the one i did lasted.i kept track of it for 2 years.when the 289 was built they hit the wall.you couldnt go any bigger so they were thin.the 260 had lots of room so they were thicker.
Sorry 312 but you would have to gain 29 cubic inches to bore a 260 to a 289. You wouldn't need to measure that overbore with a micrometer. You could use a tape measure. Like I said....If you bore a 302 out 30 thousands of an inch, you only gain FOUR (4) cubes. And that makes a 306 cube engine. It would take nearly a 1/4" overbore. I've never seen a Ford small block engine that has that much room between the cylinders and the water jackets. Of course there's always the chance I'm full of crap. I'm willing to let somebody show me the math.
The cylinder's bore diameter, the amount of cylinders, and the length of the stroke determine the engine's displacement. An engine's approximate displacement can easily be attained by multiplying..............
bore x bore x stroke x number of cylinders x 0.7854. (not a misprint)
Now if the stroke is changed (lengthened), the cubic inch size of the engine changes a bunch more then if only the bore is changed.
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