'70 or '73 318LA Which to rebuild?

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mickey_bigdaddy

mickey_bigdaddy

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I've got a '70 & '73 318LA engine. Are there any differences that I should be aware to make my decision on which one to rebuild? Or are they the same engine?
 
We had a GIGANTIC controversy on here one day where someone accused me of lying. I don't take such comments lightly. "The thing is" some blocks have blind head bolts and some don't which may or may not indicate stronger blocks

If you want much power have them sonic checked for cylinder wall thickness

http://www.forabodiesonly.com/mopar/showthread.php?t=120109

mt1r93.jpg
 
I believe that the 70 engine has higher compression stock than the 73 engine...
 
67Dart273 said:
We had a GIGANTIC controversy on here one day where someone accused me of lying. I don't take such comments lightly. "The thing is" some blocks have blind head bolts and some don't which may or may not indicate stronger blocks]
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Wow, you don't hold grudges, do you??? That's an old thread....
 
Pick the one that is in the best shape...pick the pistons to get you whatever compression or performance level you want...
 
If the heads are original, they should be the same. The '73's ought to have hardened exhaust valve seats, which should be better for the valves not receding into the seats. (We have some '68 heads and the exhaust valves have definitely receded pretty badly.)
 
Set side by side and tear down. Which ever one shows the best wear patterns on the crank,bearings and particularly the cylinder wear is the one to build.lf the 73 does have hardened seats? That's a transitional period,then use the 73 heads if their in better shape. I would find a set of "302" castings because of the closed chamber and hardened seats.
 
krazykuda said:
Wow, you don't hold grudges, do you??? That's an old thread....
Click to expand...

Nope. I just remember the "discussion." LOL

To the OP is there any reason to use "all" of just one? If one has a better block, the other better heads, etc, I'd pick the best of both, if you can
 
Robbie2734 said:
The 70 should have a steel crank.
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I don't believe that is correct, but will welcome a verified correction on that; there is a lot of confusion on this point. From all I can gather, Mopar went to cast iron in the 273's and 318's in '68 for the cars.

Examine the 2 cranks to see if either is a forged one from a truck. See here for some clues on the differences: http://www.forabodiesonly.com/mopar/showthread.php?t=218176

Check here, posts 25 and 26, for more info on years of rod and crank types:
http://www.forabodiesonly.com/mopar/showthread.php?t=91733&page=2
 
nm9stheham said:
I don't believe that is correct, but will welcome a verified correction on that; there is a lot of confusion on this point. From all I can gather, Mopar went to cast iron in the 273's and 318's in '68 for the cars.]
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FWIW my '68 318 had a cast crank and was from a Fury III. The best way to find out what type of crank it has is to just pull the pan...
 
IF the 73 heads have hardened seats, the valve job that they WILL need WILL remove the hardened surface. IF you want to run hardened seats, you will have to have them replaced. Induction hardening does not go very deep at all. Whatever wear the seats have, PLUS however much they will need to clean up will remove the hardened surface. Guaranteed.
 
67Dart273 said:
We had a GIGANTIC controversy on here one day where someone accused me of lying. I don't take such comments lightly. "The thing is" some blocks have blind head bolts and some don't which may or may not indicate stronger blocks

If you want much power have them sonic checked for cylinder wall thickness

http://www.forabodiesonly.com/mopar/showthread.php?t=120109

mt1r93.jpg
Click to expand...

I don't remember that discussion, but I agree with you, as I have seen first hand small blocks that had both blind and open head bolts holes. I know others who have as well.
 
I agree that whatever one is in best shape is the best candidate for a rebuild, depending on the purpose/extent of it. Is this going to be a full rebuild or are you just going to refresh one and stick it in a daily driver? From what I understand, the '70 318 will have floating wrist pins and the '73 should have pressed wrist pins. This may or may not be important to you. If you're just going to do a simple re ring and replace some wear and tear parts then I say use the '70 for the higher compression and floating wrist pins IF it's in suitable condition. It's hard to say pick this one or pick that one without knowing the extent of the rebuild, the condition of the engines, and the purpose/goals of the finished product.
 
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