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318 Shortblock Auto to Marine

J

jcatkinson

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I have a chance to pick up a c

I have a chance to pick up a completely rebuilt 318 LA shortblock dirt cheap that I'd like to switch to a marine application. Other than switching to a marine cam and adding brass freeze plugs what other changes would I have to make and would it even be worth the effort?

Thanks!
 
"I used marine head gaskets al

"I used marine head gaskets also, but other than that thats all I did to mine and its lasting perfect"
 
"you need a marine carb, and i

"you need a marine carb, and intake manifold also. marine manifolds have an incline built into them to keep the carb level, and the carbs are designed to keep gas, and backfire flames in the engine."
 
"You could save some money by

"You could save some money by using a carb wedge instead of a marine intake manifold. http://cgi.ebay.com/ebaymotors/Marine-12-Carburetor-Wedge-Square-Bore_W0QQcmdZVi ewItemQQcategoryZ50442QQihZ013QQitemZ230242479616QQrdZ1QQsspagenameZWDVW
If you have a mechanical choke the wedge will require adjusting the rod. In addition to the marine carb, you will need a marine alternator, marine starter, marine distributer and cap, a marine fuel pump, a lower thermostat, water cooled exhaust manifolds and elbows, raw water pump and heat exchanger if you are in salt water. The marine electrical components have been screened or sealed to prevent ignition of gas fumes. The marine fuel pump has a vent line to direct leaking gasoline (from a failed diaghragm) to the carb where it is burned in the engine."
 
I have an existing marine 318

I have an existing marine 318 and I plan to shift all the accessory components over. Will I need to purchase marine heads or can I get away with using marine head gaskets on auto heads?

Thanks!
 
"Marine and auto heads CAN be

"Marine and auto heads CAN be similar, but the head gaskets need to be stainless (with raw water cooling).

My 1985 era 360s have 273 cube Mopar heads--and that is standard for these engines. The mid-80s auto heads have MUCH larger exhaust ports (and other stuff). I've found out the hard way to use 273 gaskets, for 318/ 360 car gaskets are way too big.

Jeff

PS: For some reason, the exhaust manifolds themselves have larger ports than the heads they go on."
 
"Any recommendations on which

"Any recommendations on which style marine camshaft I should swap to? Here is the info on a remanned auto longblock I'm looking at buying: 1985-1990 Chrysler 318 rebuilt engine with a roller camshaft. This engine has been completely rebuilt with all new parts. The block was bored to .040 overbore and fitted with new Silvolite pistons. The crankshafts rod and main journals were machined .010 undersize. The cylinderheads were machined and rebuilt using new valves, springs, and seals. The valve seats and valves were machined with a 3 angle cut for better performance.

Since this engine is a 1985 will most of the accessory components from my 1976 block match up? Thanks for the guidance!"
 
Hi James

I am in the same p

Hi James

I am in the same process. I took the new cam shaft that came with the rebuild and my old marine cam to Shadbolts Cams here in Vancouver BC.

They cleaned-up the old cam instead of reprofiling the new one. They said it was much less work and my original was tested and found to be fine. You can read about Shadbolts online - they kno there cams. I left it to their best advice after seeing both cams.
 
Hey Jeff...Are you saying your

Hey Jeff...Are you saying your long block came with the 273 heads ?
 
ALL of the 318/ 360 Chrysler m

ALL of the 318/ 360 Chrysler marine engines I've seen all have these heads.

Jeff
 
"I guess that's why my &#3

"I guess that's why my '79 318 doesn't have EGR ports on it. Although, according to Barr, they changed the exhaust manifold design around '74 so they would block off those ports in the newer heads. What's the advantage...smaller cc ?"
 
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