LA 360 Rebuild - Tips Needed

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Old 01-15-2015, 08:16 AM
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LA 360 Rebuild - Tips Needed

First things first, my name is Joey Martin, I am a student at Sinclair Community College for the automotive certification due to my extreme love of cars. Couldn't be happier with the field choice I have, so let's get right down to buildin this LA.

It came out of a 1974 Dodge Charger, a B-body of course, and has been sitting since the mid 80's. The Charger received a face lift with a rebuilt 440 Magnum replacing the stock turd LA motor... this was around 1983 I want to say...

Anyways, me and a friend of mine started tearing down the 360 one night since Dad had hinted at the fact that he would like to rebuild it. So, one bare block and one year later, the engine still sits completely disassembled. So, now I am coming to you guys
My Dad can not remember if this was the 360 that he owned that had smoked, or if it were another 5.9l he had with his large number of mopars he's owned over the years. But, regardless the engine may have smoked a tad when it was pulled, so I was going to start with an engine rebuild kit that would take advantage of reusing the stock pistons (even though more compression would be the idea, my pocket book is quite thin atm) with a ring kit along with the usual crank bearings and main seals.

Now, what to do after the basics of a minor overhaul, is where I am stumped. I don't know what kind of cam I should get, especially since this is my first engine rebuild ever. I don't know if I should junk the single plane intake manifold or if I should try and reuse it. I don't know what kind of head work would be required of an engine that had a street/comp cam, nor do I know what valve work would need to be done.

So, like I said I am in need of some tips. So, I am coming to you folks to hopefully shed some enlightenment on my current predicament.
Old 01-15-2015, 08:25 AM
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Are you doing all the Machine work at the College?
Old 01-15-2015, 08:40 AM
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Originally Posted by RacerHog
Are you doing all the Machine work at the College?
Unfortunately at the moment, that is a negative. There is a course that I plan to take within the next semester or two that involves building a high performance engine, and all the machine work is done by yourself, and the only out of pocket expense is whatever kind of performance parts you want to put on it.
Old 01-15-2015, 10:47 AM
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Well.. For the first timer... Do a stock rebuild.. Best way to learn...
Or is Stock not were you want to go?
Old 01-15-2015, 02:54 PM
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Welcome Joey. When you start things like this get good precision measuring tools and measure, measure, measure. The bolt together paint the block fun stuff comes later.

First get the rebuild tolerance data and measure the block for bore diameter/out of round and allowable bore taper before doing anything. If you have a good candidate take it to a reputable machine shop and have them clean and magnaflux the block. The cleaning may require new cam bearings, oil bypass plug and oil drive bushing. You must have a good foundation to start from. Same cleaning, mag/crack checking for the heads.

Now you can measure your crank and rods for bearing sizing. Measure your valve stems check guide clearance, visual inspection on valve/head seats.

At this point your ready to decide on head work, possibly a bowl clean-up, three angle grind, possibly port mach if larger intake wanted.

Camshaft should be last and decided with head modifications and desired rpm range.

Most camshaft manufacturers have great teaching videos and printed data on their web sites. Go slow, be thorough, take notes and photos and most important, paint it a Mopar colour.

Dan.
Old 01-15-2015, 05:02 PM
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Smile

Most of the time a smoking L.A block just needs valve seals its a very rare event that the oil rings have failed. These arent chebys or furds.
Just a quick note for ur rebuild
Old 01-17-2015, 04:09 PM
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Hey thank you guys very much, and coincidentally-as Coronet 500 had said- we just learned on Friday in our engine systems class how important measuring bore and crankshaft sizes for taper and out of round characteristics. And I totally agree with you, Racer Hog, about the stock rebuild being the best way to learn. I guess my goal for this build would be to rebuild it almost stock, lol. I'd like to get as much power out of her as I can with stock essentials (crank, bore, intake manifold, and head. Basically look at it like a budget street build I guess, haha.

Last edited by B055; 01-17-2015 at 04:12 PM.
Old 01-17-2015, 04:43 PM
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If you happen to change your plan and decide to change pistons, first look at compression height. Learn your block height minus (1/2 stroke plus rod length) keep this dimension handy as it will decide how far "in the hole" the piston will be and your compression ratio.

Something I do even if it is a stock rebuild is weld in a decelleration baffle in the oil pan, easy good insurance for oil control.

Check your oil passages from your right (passenger side) oil galley down to the main bearing saddle. There have been reported some not fully drilled or step drilled and restricted. I have a couple of 9/32" x 12" long drill bits I pass down all 4 to be sure.

I also will do a little rotary grinding (porting) of the rear main cap oil passage and pump outlet to assist in smooth flow.

These are just a few simple no money things that can be done to help your crank and rod bearings.

Dan.
Old 01-17-2015, 06:06 PM
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DO use brass soft plugs. and anti-seize compound on the exhaust bolt threads. tighten the exhaust bolts to 70-80 % of full torque first time. then after 5-7 full heat cycles take to full torque.
Old 01-17-2015, 09:13 PM
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Again, thanks for the info!! I have a poor personal experience of a exhaust header bolt on another motor my dad has for his charger (the 7.2 440) and we bent a craftsman wrench trying to get one of its stock headers off, lol.

Anyways keep the info coming! Maybe give me more info on cam upgrades or valve train/intake manifold changes to get some more mid range torque out of it?
Old 01-18-2015, 05:17 AM
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The stock 340 4 speed cam is a great cam and sometimes overlooked. I have a Comp Cam XE 256 H in our 318+.030" truck engine, smooth idle, high vacuum, low end grunt with a surprising top end. I'll look some up for you.

http://www.allpar.com/mopar/4bbl.html

http://www.hotrod.com/how-to/engine/...er-360-engine/

Tons of ideas out there.

Last edited by Coronet 500; 01-18-2015 at 05:25 AM.
Old 01-18-2015, 06:11 AM
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Quick cam recommendations. Advertised duration I/E, lift I/E, LSA.

OEM 340 4sp......256/268 .447"/.455" 110' stock springs and converter.

Lunati 10200701. 256/262 .454"/.475" 112".stock springs and converter.

Lunati .........702. 262/268 .475"/.494" 112' new springs recommended.

Comp xe256h......256/268 .447"/.455" 110' 360 springs ok I changed to 901's

Camquest program shows 300hp 400tq with xe256h cam in a 4bbl 360. When you start looking at the articles that say get 400hp from your low buck 360, it's usually done with the camshaft (big). Needing valve springs, maybe rocker upgrade and the rpm range will start getting higher requiring higher stall converter, large exhaust and possibly rear gear change to utilize the power. Most will over cam their first engine.

Dan.
Old 01-18-2015, 10:29 AM
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Originally Posted by Coronet 500
Quick cam recommendations. Advertised duration I/E, lift I/E, LSA.

OEM 340 4sp......256/268 .447"/.455" 110' stock springs and converter.

Lunati 10200701. 256/262 .454"/.475" 112".stock springs and converter.

Lunati .........702. 262/268 .475"/.494" 112' new springs recommended.

Comp xe256h......256/268 .447"/.455" 110' 360 springs ok I changed to 901's

Camquest program shows 300hp 400tq with xe256h cam in a 4bbl 360. When you start looking at the articles that say get 400hp from your low buck 360, it's usually done with the camshaft (big). Needing valve springs, maybe rocker upgrade and the rpm range will start getting higher requiring higher stall converter, large exhaust and possibly rear gear change to utilize the power. Most will over cam their first engine.

Dan.
Thanks, that's some pretty useful information you got there. I guess my next question would be, what carbs do you guys recommend? Unfortunately being the LA it only has a single plane intake manifold, I've heard of splitters and such, or just buying a new intake manifold... What do you guys recommend?
Old 01-18-2015, 03:14 PM
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I don't get the single plane, is it aluminum, is it 4 bbl?

My first choice is the OEM cast iron 360 4 bbl. Plentiful, inexpensive and excellent design.
Old 01-18-2015, 03:52 PM
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if you get an edlebrock AFB. the rods are set with to much difference in the power step and the cruse step. try readjusting them to the rod size's more like chrysler put on O.E.M. AFBs. this aplays a chrysler engine that is close to stock that chrysler made. a full out race engine is MUCH different.
Old 01-19-2015, 09:52 AM
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Originally Posted by Coronet 500
I don't get the single plane, is it aluminum, is it 4 bbl?

My first choice is the OEM cast iron 360 4 bbl. Plentiful, inexpensive and excellent design.
It's a 2bbl dual plane my mistake. So can you enlighten me more about the stock 4bbl? I'll do some of my own research but I would like to hear it personally from the perspective of someone else.
Old 01-19-2015, 03:04 PM
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If you look through advertised information from all the aluminium manifold manufacturers and see their RPM range, you'll get the idea what type of driving they are designed for and the selection is vast.

The late 60's 340 manifold is still looked at as one of the best. The carb flange was changed and most of it's design was carried over to the 360 4 bbl manifold. An aluminum obviously saves front end weight which has it's advantages but there is the additional cost.

A cast iron manifold can be found for $50.00 most anywhere.

I truly believe, for value and performance potential, it can be called the best small block Chrysler manifold.

If later, funds are available and performance goals go up, then it's the easiest component to change later.

Dan.
Old 01-19-2015, 03:48 PM
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Originally Posted by Coronet 500
If you look through advertised information from all the aluminium manifold manufacturers and see their RPM range, you'll get the idea what type of driving they are designed for and the selection is vast.

The late 60's 340 manifold is still looked at as one of the best. The carb flange was changed and most of it's design was carried over to the 360 4 bbl manifold. An aluminum obviously saves front end weight which has it's advantages but there is the additional cost.

A cast iron manifold can be found for $50.00 most anywhere.

I truly believe, for value and performance potential, it can be called the best small block Chrysler manifold.

If later, funds are available and performance goals go up, then it's the easiest component to change later.

Dan.
Excellent. But, there is one thing that I just can't get a reliable foothold on.... What is the best website to buy 360 parts from? Stock or performance...

If the bores are in spec along with the crank journals, what should be my first plan of action after a machinist? Buy a kit for the bottom end?
Old 01-19-2015, 05:47 PM
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Kit covers a lot of ground. 2 engines ago my son hand polished the crank, we measured everything, bought undersize bearings, he honed to break glaze, new rings and plastigaged main and rod journals, new rear seal = short block.

Last engine had our machinist measure crank, needed 10, 10 grind, he sized and supplied all bearings, pressed on new +30 pistons, bore/hone block, install cam bearings and oil drive bushing, no decking required. Picked it all up, plastigaged main and rod bearings, new rear seal = short block.

Both of these scenarios beside any machine work are bearings, rings and seal. After this next step is gasket set and away we go.

I,m not much for buying "kits" as there are many variables, measuring yourself or by a trusted machinist then buying individual components can be more cost efficient with no surprises or doubling up.

Last edited by Coronet 500; 01-19-2015 at 06:45 PM.
Old 01-20-2015, 09:36 AM
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Well it looks like I have some studying to do. Especially on camshaft and intake setups, as I know nothing of the carburetor world. My dad has a twin ram setup with 2 holley four barrels that he had for his 440 (which I'm also wanting to do some tinkering with) and he could never get them to tune in right so I may just fiddle with them and try to understand the concept and get familiarized.
Old 01-20-2015, 02:37 PM
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Basics. http://documents.holley.com/techlibr..._tech_info.pdf
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