Author Topic: 318 Mixin and Matchin  (Read 1516 times)

Offline asm74

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318 Mixin and Matchin
« on: August 30, 2006 - 10:04:25 PM »
Hey moparians! 

My 73 project continues slowly, and as the shell awaits pickup for the body shop, Ive been considering my engine options.

I have the original 318 LA (with an after market 4bbl carb and intake that I'll probably junk) and it looks to be in good shape considering the 33 years of abuse. I've torn it down and am thinking that I'll rebuild this engine with a bit more oomph but retain stock looks.  (A little background: I'm building this car for my wife, who wants a muscle car to look cool in, not necesarily something to race)

I'm looking at the 400hp 318 build thats been mentioned on the site before but here's my question.  I also have a 95 5.2 magnum out of a dakota.  Its an MPI engine but has roller lifters and magnum heads.  Can I take the heads of the magnum, drop them onto to the LA and get instant power?  Or should I start with the Magnum block, get a carb and intake for that? 

I'm looking for the cheapest bang for my buck, given I have 2 versions of the same engine.  So far I plan on getting steel roller rockers, engle K58 cam and possibly speedpro forged pistons.

73 Challenger




Offline Chryco Psycho

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Re: 318 Mixin and Matchin
« Reply #1 on: August 31, 2006 - 12:27:21 AM »
the Magnum has the advantage of the roller cam & block designed for them , it would ba cheaper to get a carb intake for the Magnum & just drop it in

Challenger - You`ll wish You Hadn`t

Offline GoodysGotaCuda

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Re: 318 Mixin and Matchin
« Reply #2 on: August 31, 2006 - 01:44:32 AM »
How much $ do you have to throw at it. And how fast do you want to go?
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1976 Dodge Warlock
1972 Barracuda - 5.7 Hemi + T56 Magnum

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Offline asm74

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Re: 318 Mixin and Matchin
« Reply #3 on: August 31, 2006 - 09:11:16 AM »
Thanks for the responses.

I don't want to break $2K on parts for this engine.  Fast?  I'd rather have lots of low end pick-up rather than top end power.  Again, this is supposed to be reliable and efficient before it's supposed to be fast.  Can I drop the engle cam and new rockers into the magnum or are the stock rollers a better fit?

decisions....decisions.....
73 Challenger

Offline moper

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Re: 318 Mixin and Matchin
« Reply #4 on: August 31, 2006 - 09:51:34 AM »
Let's see...$2K...Well, if the Magnum runs well now...  I'd pull the heads, have them  set up for performance, maybe a little bowl cleanup, good springs, retainers, etc. I'd mill them about .020, and have them drilled for the LA intake pattern (easy deal for a shop) and gasket matched for the LA port. Run a hydraulic roller cam, reusing the lifters and spider setup. Get a Performer 340/360,  and drop it in. No rebuilding of the lower end, I'd leave it totally alone. If you take it apart, you "might as well" rebuild it, better pistons, etc. But if you dont have to, dont bother.

Offline asm74

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Re: 318 Mixin and Matchin
« Reply #5 on: September 01, 2006 - 12:49:39 AM »
Next question would be what to do about the spark... Can i safely drop in an MSD or mopar ignition system in place of the computer controlled dizzy?  I did a fit test and the original unit from the LA fit the magnum perfectly. so thats good innit?
also, will leaving the crank sensor disconnected be okay? 

Sorry, I'm a bit new at this, and I have all the books, but they dont really cover the "frankenstein" approach to the hobby  :icon16:...
73 Challenger

Offline Chryco Psycho

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Re: 318 Mixin and Matchin
« Reply #6 on: September 01, 2006 - 05:55:18 PM »
there should be no problem using the older style dist in the magnum block with a mopar or msd ecu

Challenger - You`ll wish You Hadn`t

Offline asm74

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Re: 318 Mixin and Matchin
« Reply #7 on: September 04, 2006 - 12:43:20 PM »
Thanks alot for the feedback.  Looks like this motor will come together faster than I expected. 

Still looking for a good body shop in the S.F. Bay Area..... :dunno:
73 Challenger

Offline phf

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Re: 318 Mixin and Matchin
« Reply #8 on: September 10, 2006 - 04:57:29 PM »
i got a 92 5.2l and i pulled the fuel injection unit off to replace it with the edelbrock rpm air gap and a 650 thunder series carb. it all bolted together nicely, but idk how well it will run till im done with the wiring harness, so once i know, ill let u know. but ya, for best prices go to a local kragen and order the parts through them, way cheaper then summit or anything else, too bad they dont carry all the parts i need. good luck with ur project though



 :ylsuper: stan
« Last Edit: September 10, 2006 - 05:00:54 PM by phf »
I'm jus here to feed my fish rice

Offline phf

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Re: 318 Mixin and Matchin
« Reply #9 on: September 10, 2006 - 05:00:34 PM »
o ya, and i forgot to mention the ignition. i talked to several mopar ppl around here and they all said that going aftermarket distributor and coil will be the best way cuz its more performance and the computer controlled units must go anyhow, so might as well
I'm jus here to feed my fish rice

Offline asm74

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Re: 318 Mixin and Matchin
« Reply #10 on: September 11, 2006 - 12:24:46 AM »
Wow, Stan, talk about coincidence.  I just got my RPM air gap and Performer 600 carb, and so far everything is going together really nicely.  Im going to try to re-use the original distributor, coil, and electronic control unit (in mock up it looks so cool).  One thing I did get into a little bind on was the flexplate. Don't know if youve got there yet, but my 904's torque converter wouldnt bolt up to the 95's stock flexplate, so I ordered a b&m plate that seems to do the trick.  There was about a third of an inch offset on one of the bolts. 

What parts are you using for water temp and oil pressure sending units? 

Still to come:
   Fuel pump, (probably going to spring for a combo electric pump with regulator)
   Headers
   Fuel Sending unit
   Oil Pan
   
   
« Last Edit: September 11, 2006 - 12:33:11 AM by asm74 »
73 Challenger

Offline chrisII

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Re: 318 Mixin and Matchin
« Reply #11 on: September 11, 2006 - 02:53:14 PM »
you can easly use an LA intake and redrill the holes to 90* like a magnum. then use short pieces of tube cut at an angle to apply proper force. (look at your magnum intake it will make sence)the ports are supposed to match up..never tryed it but ive read up on it.
   I would use the magnum engine and possibly just install a mild cam.