A few engine questions

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Sinister.

Sinister.

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How similar are small blocks?
Apart from the bore, is the BLOCK of a 273-318-340-360 pretty much the same?

Often I hear about people saying that you shouldn't bore more that .060 over.
But from what I can tell, all the small blocks are the same, so why wouldn't I be able to bore a 318 .13 over and use 340 pistons?

Just coming with ideas here, but I was thinking since I have so many 318s at my fingertips, why not build one.
So far I'm thinking bore it .13 over w/ 340 pistons, 360 crank and heads. A good family friend has a fairly large cam that he is willing to give to me, I have a 650 cfm 4 bbl Holly (or two ;) ) that I could put on it. I'd still have to decide on intake.

Is it possible?
 
The 273,318, and 340 block are similar with the same stroke but you can`t bore the 318 enough to get the 340 pistons in. About .040 over is safe for most blocks. The 360 has a different main journal size and a much longer stroke. You can still build a stout 318 without breaking the bank.
 
So there are small differences between the two blocks that will make the difference?

I was unsure if the blocks were the same, just bored. But I guess not.
 
Yeah, if there weren`t the differences, we would all be running 273`s bored .500 over.:toothy10: You can probably pick up about 6 cubic inches with a .030 over bore on a 318. The secret is to pick good parts, good oiling, close and consistent tolerances put together in a sterile environment. Pick a good valve train and you can get it to wind high while staying together. :read2:There`s a lot of info right here at FABO that can help you build a crazy 318. Go for it!
 
What you are wishing to do is almost impossible without spending a small fourtune in custom machining. If your bore the engine much more than .030 oversize you will start to encounter over heating problems. You encounter problems with the piston skirt to crank shaft clearane . The 360 oil pan will not fit the 318 block.The mopar performance engine manual may offer help to you with some of your questions ?
 
I think it's Hennsely racing ...there looking at all the 318's they can get there hands on. It seems that the factory has alot of variances in what sleves they used in the block. Some of the blocks, a selected few are bored over to 4.00 after they pass a sonic check and deemed OK for this use.
There making 4.00 bored X 4.00 inch strokers from the 318.

Otherwise, the less you bore a cylinder out, the stronger it will be. Thicker walls flex less and will have a longer life and a cooler running temp.
It takes a good bit more money to sonic check and then bore a teen out to 4.00.

The 360 differs with the journal size, oil pan and stroke of the crank. After that, there basicly the same. Engine mounts can be divided into 2 groups. Narrow 340/360 drivers side mounting points and 318/273 wide drivers side mounting points.
360's are externally balanced and the '73 - 340. (Some 72's, late year I'm told.)
 
Well darn. I've always wondered about that, but never really asked. Sounds almost crazy enough to work!

Back to researching, and the drawing board.
 
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