1971 factory 318

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DusterDaddy

DusterDaddy

sledgehammer mechanic
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Was the 71 318 a decent motor? found a low mileage unit in a coronet for sale.
Is it a good candidate to freshen up with an intake and small Holly and 340 exhaust manifolds?
Thinking it might be good motor for my 74 Duster project.
Any thoughts would be appreciated.
Thanks
 
Absolutely...Good year.
You could turn it into a good runner. Snap it up.
 
Like any USA 318 (built for US production cars) a 318 needs more compression so new pistons are in order as well as a true double roller timing chain. Then you need to get a better heads (bigger valves) for it.
 
I think it would be a good motor to get your project running.
71 it may even have a steel crank in it, the crank in my old 71 challenger deputy was steel.
 
There all steel! LOL It is a forged crank. Mill hour heads down for cheap compression.
 
rumblefish360 said:
There all steel! LOL It is a forged crank. Mill hour heads down for cheap compression.
Click to expand...

I totally doubt this has a forged crank, likely a 1 in 10 chance. My car's original, never been apart other than the oil pan 1970 318 has a cast crank. They started making them with cast cranks in 68 or 69.
 
Really,
I had a 69 318 in a truck, and a 71 challenger with original motors and they were forged cranks.
Every 72 and newer that I have seen are cast.
 
rumblefish360 said:
There all steel! LOL It is a forged crank. Mill hour heads down for cheap compression.
Click to expand...

Nope, they are not all forged. All neutral balance, but not all forged.

goldduster318 said:
I totally doubt this has a forged crank, likely a 1 in 10 chance. My car's original, never been apart other than the oil pan 1970 318 has a cast crank. They started making them with cast cranks in 68 or 69.
Click to expand...

I thought '70 was the changeover year, but I definitely could be wrong since I don't have anything older than '71. I do know for a fact the 318 in my '71 EL5 Dart GT came with a cast crank in it, the bottom end had never been apart before I started my rebuild and its an all numbers matching deal.

I do know the trucks kept the forged cranks longer than most of the passenger cars did, but I'm not sure why the Challengers would have. I suppose my '72 might have been helpful, but it came to me with a 1983 318 in it (also a cast crank...)
 
From "How to rebuild your small-block mopar"

year cid material cast#/forge#

64-67 273 forged 2128278, 2128869, 2205700

68-69 273 cast 2658268, 2658393

67-73 318 cast 2658278, 2658393

74-86 318 cast 2658278, 2658393, 3462387
2658391

68-72 340 forged 2532457, 2843868

73 340 cast 3462387

71-86 360 cast 3418640, 3418641, 3418642


My engine has a 2658393 crank. It even still has the original steel shim head gaskets so I know its never been apart.
 
You don't need a forged crank for what you're doing, don't worry about it. Grab it, freshen it, and have fun.
 
Above post,X2. Spend the money,check the rings ,bearings,oil pump.Then starts the fun.
 
Any thoughts would be appreciated............ok.

If you can here it run and it runs good and you see no smoke then.......

Check the bearings on one rod and one main bearing, if they look good run it.

Buy a good cam with a set of performance valve springs,intake,carb and a mopar performance ignition ,headers ----and your all set.

Don't over think it.......the major difference between a stock engine and a performance engine is not in the pistons and or short block.
It's everything else just mentioned.
 
Above post,on the money. Number 1 main,number 1 rod. Furthest from the oil pump.
 
IMO the pistons will make a huge difference, otherwise you're lucky to get high 8.x compression with anything else. However, if you're looking for something temporary (whether a few months or a couple years) if it's a running engine, it's easy to do a cam and some headwork and have a fun engine. Just don't expect to beat anybody unless they have a stock 318 :) I did this with mine, and I'm happy to be able to cruise it, but long term I'll go with something faster.
 
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