340 end cap question

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Quikitty

Quikitty

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I am having my 69 340 rebuilt. I sent everything to the engine builder. The engine was apart ( i bought it that way) and it seems I am missing the end caps.
Are the end caps for a 318 or 360 the same as a 340?
If so, any ideas as to where I should pick up a set?
Thanks
Jay
 
360's have a bigger main bore so they won't work. I believe 318's have less meat and not as strong, but not 100% sure, especially on the rear cap. Either way, you will need to check things and probably have the main bores align bored an honed because the replacements probably won't align perfectly.

Are you missing all 5 or just #1 and #5?
 
The 318 and 340 are the same, it seems the 360 is different. I would have the machine shop align bore the mains as the new ones will be new or from a different engine. I have seen were the crank will not rotate if the caps are mixed up, that is why they are numbered.
 
Journal size for a 318 and 340 are the same, the caps for a 340 are taller.
 
I will through this in and if I am wrong someone correct me, but when he has the aline bordering done will he have and issue bolting up his tranny? miss alinement?
 
I have never had an align bore done, but I would think there would be no fitment issues with the tranny, the aligning is strictly for the crank to center it perfectly with the caps.
 
Snake said:
I will through this in and if I am wrong someone correct me, but when he has the aline bordering done will he have and issue bolting up his tranny? miss alinement?
Click to expand...

It's possible depending on how much has to be machined and how good alignment was to begin with. Can also loosen the timing chain a bit.

Caps will be machined down on there mating surface creating a semi oval shape and then bored back to round. Material is removed from the block side also in the process effectively raising the crank centerline a bit.
 
I have the #1 and #5 caps, it is all the rest that I am missing.
I think 1 and 5 are the most important. might see if the machine shop can make caps 2, 3, and 4 with out killing me in machining costs.
 
Actually, #3 and #5 are different. #3 takes the thrust bearing. #1, 2, and 4 are basically the same and can be interchanged if line-bored and honed or more easily machined. Somebody here or on moparts.com had some aftermarket caps for sale. But I don't recall if they were 340 sized and if it included all or 1 through 4.
 
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