Mods for old 318?

Hey all,

I am rebuilding a 68 Cuda and will have the engine out shortly. What mods can I do to my 318 to get a little more out of it? I bought it last month and I know the engine needs to be tuned up a bit, other than that it runs great. It sat for a year, the timing is off a bit and the carb is gummed up as well. It apparently has a new bottom end but can't confirm it, on top of that it has a huge 4 barrel Edlebrock carburator sitting atop an older intake manifold. What cam and intake manifold can I install to get a little more out of my engine. I might just bite the bullet and tear the whole engine down. The meter reads 925 hours and not sure if the heads are original.

Thanks!

It is not quite as cheap to upgrade an old reverse rotation chrysler as say a sbf or sbc but it can be done. Marshall Morgan has what is now a 340 running pretty well in a 70 mustang (at least I hope it is running these days I havent talked to Marshall in a little bit). It will take pulling up some old posts here but there are some details on components and cooling system mods that were required to run an after market intake manifold. There was a bit hotter rr cam available for these engines at one point and there may be a few rolling around or available special order if you look hard. Reid Pinkham maybe able to point you in right direction.

give theses guys a call They seem to be the mopar on the water experts.

What I would do is ditch the 318 heads in favor of any flavor of 360 heads. If you go with a 75-86 style smog head you will need to mill them to get the compression up to desired ratio unless that engine being an older marine engine is slinging flat top pistions then you might be ok.

On the other hand, your best power alternative would be to find a set of 87-91 360 swirl port heads. These heads untouched offer simmilar flow numbers to that of the 340 "x" or 360 "j" head. You also have the benifit of quench pads for better compression and more efficent burn/less detonation on pump gas. The only problem with these heads are that you will need to locate a set of hollow push rods and magnum style lifters because the valve train in these later heads are oiled through the push rods. If you could locate a junkyard motor you could nab the heads and pushrods. All I would do to these heads are have them checked out and get a good 3 angle valve job. These swirl port heads can be found on any 360 that had throttle body injection.

Camshaft wise you wont need anything to agressive because you aren't looking for rpm in this case just good power where you need it. If you want something simple you could go with the factory 340 hi po grind camshaft. It will make good midrange power at your wot rpm and will have a nice idle that will not be choppy but will sound a little hotter than stock. Being marine I might go with a more modern dual patern cam to take full advantage of low range and higher rpm power with driveability. If you go with the newer heads there are lots of flat tappet lifters availiable that offer pushrod oiling.

Carb. should be simple. Being marine I would probably go with a vac. secondary carb with around 600 cfm. With a 318 anything bigger than 600 would be overkill. Timing will be happy around 32 to 35 degrees total advance. This setup would be happy with premium fuel but if you reduce timing a bit being marine and running less water temp you might be able to get by with 89 in it.

Intake manifold should be a simple dual plane. The m1 mopar performance is a good choice being a stock 360 casting in aluminum. This intake takes my 3850 race weight 360 67 satellite to 13 teens in the 1/4 on street tires so it should be more than enough for a hot little 318 on the water and make good low range to target rpm power.

If you stay with points make sure the points and condensor are new and adjusted correctly and you could run some type of hotter coil that is points compatable.

I have to adjust my thinking in boats because I shift my 360 at 5800 and it goes through the traps at 6100 rpm.

All this I think would be make a hot little setup for you and get you making the power where the boat needs it rpm wise. We can get more in depth on camshaft sellection when you decide what you want. Is this standard or reverse rotation? If its reverse the other guys will have a better idea on where to pick up a cam.