343 with Dog Leg heads?

mstrcrftr wrote: Boris Badanov wrote: 360 is a stroker 343 with better heads and a higher deck height.   Somewhere in about 1973??? the crank was changed to fit the Chrysler automatics. Thats what i was thinking as well.  Although the 343 and the 360 were available in 1970 they were different deck heights

The 360 took the place of the 343 in 1970. The 343 ended with the 69 model year.

Really no issue with intakes, just use the correct one for the block you are running. Square port and dog leg heads have basically the same intake port location and size. Plenty of intake options, here are a couple to kick off with:

RPM Air-Gap AMC (non-EGR, for 1967-69 290-390 c.i.d.) P/N 7530
RPM Air-Gap AMC (non-EGR, for 1970-91 304-401 c.i.d.) P/N 7531

Torker for the early engines 2935
Torker for the later engines 2930

The 2935 was discontinued in 2009 so you are stuck with used, but the 7530 should still be available new although that is possibly discontinued now too.

Taking a little bit of compression out with the bigger chamber heads might be a good thing depending on what sort of fuel you have access to and want to pay for. 10.2:1 with iron heads and no quench by having the pistons way down the bore is going to need some highish octane fuel. I think that quench is one of the most important things (besides the dog leg heads) you gain with the 360 over the 343, the extra few cubes is not going to make an earth shattering difference to performance.

Using a 360 crank is a good solution in these engines, but remember that AMC raised the deck as well as increasing the stroke when they developed the later engine. What his means is that you really need a piston with a slightly shorter compression height than the regular AMC 360 piston or you can use some other tricks to achieve the same outcome otherwise you can end up with the piston sitting proud of the block.

WesternRed wrote: ....... otherwise you can end up with the piston sitting proud of the block.

I haven't heard that term in years!  Decades ago a friend and I were working on his Norton motorcycle and there was an 'O'-ring in a bore.  The service manual said to make sure the 'O'-ring was 'proud'.  It took us a little while and a lot of questions to find out that's the English term for 'protrudes' or 'sticks up above the rest'!!

With the 1.581 compression height Speed Pro pistons you should get away with it, Wiseco are 1.590 Compression height and I have factory spec down as 1.601 from somewhere. General consensus is that the aftermarket pistons often have a slightly lower compression height to allow for decking the block. Anything like this you really need to measure up, because you probably don't know how far a block has already been decked in nearly 50 years since it rolled out of the factory and all of the factory measurements has a bit of tolerance in them too.

If the 343 is just a temporary solution, then I wouldn't get too carried away with it, stick with the square port heads, grab an aluminium 4 barrel intake or just use the factory cast iron on and stick a bit of cam into it.