340 r.i.p.
I am leaning towards a magnum roller cam motor. I found a 97 magnum 318 with high mileage 177k for $200. When everyone recommends a magnum are they talking one to rebuild or one with lower miles and put in with some performance mods. Are magnum motor any more or less to rebuild than a LA motor? If i do go magnum it would be carburated and look like an LA, I just always wanted a classic muscle car look under the hood, no computer, injectors, lots of wires.
The Magnum is a good engine. If you start tinkering with camshafts, you have to be careful with valve spring crush and be sure that the part you are looking at gives specs for a 1.6 rocker.
If you want a carb manifold for the Magnum, Mopar Performance makes a good dual plane manifold with Magnum or Magnum and LA manifold to head bolt patterns.
As mentioned above, the timing cover needs to be swapped for one that has provisions for a mechanical pump. The one from your 340 will work. Also, you will need a camshaft extension to run the mechanical fuel pump eccentric on the shorter magnum cam. -
http://www.hughesengines.com/Index/...entric+extension&submit=Go&searchmode=keyword
Or, go with an electric pump.
The nice thing about used Magnum engines is that they typically show little wear. I'd still tear the pan, main caps and other gear off to put new seals in and check everything out to be sure, as you well know, examining that disaster, but they generally still show cylinder hatch from being injected.
The magnum manifolds may or may not clear power steering. I was able to clearance some 360 truck manifolds to work with my power steering, you may be able to do the same and if you get the manifolds with the engine, it doesn't hurt to take the manifold and studs off of the driver's side and see how everything looks, before buying 340 exhaust stuff.
If you were sneaky with the valve covers, oil pan, manifolds, etc, you could make it look like a 340, with the exception of the balancer. I suppose you could internally balance the crank and make it even more difficult to tell, aside from the casting markings.
Cost is about the same, but given that most shortblocks have little wear, you may not have to do anything, but a simple cleanup and seal, maybe with some bearings. The heads are hardened exhaust valve seat, closed chamber, higher flow runners, etc. So as long as you have something typical to start with, again, it will likely take less to do.
all 360 Chrysler engines use a 4.000" piston from the start and there are a ton of manufacturers that make that size, because it is common. The 340 used the shorter crank and a 4.040" piston, so if you move up on a 340 and go .030", you buy 4.070" pistons, which drops manus down to chrysler specific catering manufacturers and the price goes up.