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-   -   318 build help (https://moparforums.com/forums/f81/318-build-help-14376/)

CThompson 03-04-2013 07:18 PM

318 build help
 
I'm starting with a all stock 318 2bbl in my 1979 Dodge D100. It has a build 727, and 8 3/4 rear. does have true duals with no cats.
I bought a 360 Mag that I'm going to build next winter (and to save up for 600+ hp) cause I am going on a tour with the army in months:pistol: and I want some thing to play around with for now.
:doh:
but right now i was to mill the 360 heads, 4bbl RPM intake, headers, on the stepside. I have the heads and the intake, and headers. I'm just wondering whats needed to do the head swap (push-rods, and mill specs for both intake&heads)

Any help is thankful

CThompson 03-04-2013 09:29 PM

If I was to mill the 360 heads .060 how much would I have to have the intake milled? And could I use OEM 360 mag pushrods on the 318 block with the 360 mag heads being milled?

PK1 03-05-2013 03:56 AM

Push rods need to be measured for every motor especially when a head is decked since you lower the distance between rocker arm to lifter cup. AND remember the Magnum is an "oil thru pushrod" motor. Not the same as the LA motors.

As for milling the intake. There is a chart most machine shops have to make this easy. What heads do you have and what valves are in them? If you machinest gives you the "deer in the headlights" look regarding the intake mil we can do the math for you.

You plan sounds solid and well thought out. Be safe on your tour!

Gorts 5th 03-05-2013 06:54 AM


Originally Posted by CThompson (Post 98930)
I'm starting with a all stock 318 2bbl in my 1979 Dodge D100. It has a build 727, and 8 3/4 rear. does have true duals with no cats.
I bought a 360 Mag that I'm going to build next winter (and to save up for 600+ hp) cause I am going on a tour with the army in months:pistol: and I want some thing to play around with for now.
:doh:


God bless be safe.
sucks that your off to fight a war to steal some countries natural resources for the banker elites..
My respects. hope you make it through in one piece .
ctompson rei!:clap:

Gorts 5th 03-05-2013 06:57 AM

The magnum heads how much flow improvement and other improvements over the l.a. 360 head?
and what is involved in a swap will the swap ?

TVLynn 03-05-2013 10:35 AM

To put the 360 Mag heads on your 318 LA block you need to change everything except the long block. IS it 4 wheel drive ?? IF NOT consider going to a 440 and build a 500" torque monster.
A 600hp small block is NOT realy a street motor. If you 450-500 hp you would probably do better especially with a heavy truck. and the need for a 3500 stall converter

CThompson 03-05-2013 03:31 PM


Originally Posted by TVLynn (Post 98969)
To put the 360 Mag heads on your 318 LA block you need to change everything except the long block. IS it 4 wheel drive ?? IF NOT consider going to a 440 and build a 500" torque monster.
A 600hp small block is NOT realy a street motor. If you 450-500 hp you would probably do better especially with a heavy truck. and the need for a 3500 stall converter

It's 2wd. And I don't want to to be street able. I have a 440 in my dart and I'm building a 440 in my 31 rat rod. And my truck with me and a full tank of gas is 3100 lbs.

What if I milled the heads .060 could I use OEM mag pushrods or not? If not what ones do I need.

PK1 03-05-2013 04:18 PM

Pushrods wont work. You are gonna need somewhere in the ballpark of 7.625 for a mag head swap depending of head gasket and deck height. Stock magnums 6.9.

Its not hard to put mag heads on an LA. Same exhaust pattern and head bolt pattern. BUT intake bolts are different.. If you have a 440 in a 31 you can prob have the skills to tig up the intake bolt holes and redrill for the mag vertical bolts. Just use a gasket as a template.

You need an oil thru lifter to pull this off. You can use the old AMC style. Or any aftermarket ones that cross backwards into an AMC application. The rockers arms on the magnum heads are just old AMC stuff. Someone raided the parts pin for sure.

CThompson 03-05-2013 09:11 PM


Originally Posted by PK1 (Post 98999)
You need an oil thru lifter to pull this off. You can use the old AMC style. Or any aftermarket ones that cross backwards into an AMC application. The rockers arms on the magnum heads are just old AMC stuff. Someone raided the parts pin for sure.

You have any ideas on the rocker arms? This seems alot harder that I read about. I might look for some LA360 heads. Mill them and put the high rise on it.

Gorts 5th 03-06-2013 05:35 AM

do these magnum heads flow better than 360 L.A. heads?

CThompson 03-06-2013 05:56 PM


Originally Posted by Gorts 5th (Post 99051)
do these magnum heads flow better than 360 L.A. heads?

I was told be a few people i know that mag heads do.

PK1 03-06-2013 06:26 PM

Mag heads are the best flowing small block 360 heads made by the factory. And use a very light 8mm valve.

Zoomer59 03-09-2013 10:55 AM

360 mag Heads
 
Doesnt Chrysler sell a kit to do this conversion?

PK1 03-09-2013 12:38 PM

They use to. But it was just a collection of off the shelf parts that they packaged together for convenience. You may still find it but I think it went unavailable about 5 yrs ago.

Lifters, 5/16 oil thur pushrod ( size to motor) , reuse the mag rockers. Done.

HT2011 is the part number from Summit for the lifter (I believe) They are 3 bucks each. Comp sells them too #822.. (again.. Im going from memory so check)
Pushrods: you can use any brand you like. The magnum valve train doesn't use guide plates so they don't need to be hardened.

If you get a cam or have an idea.. let us know and we can spec a spring. Mag heads are finicky with the 1.64 installed height and anything over 1.44 will hit the head bolt.

CThompson 03-10-2013 01:38 PM

Pushrods
 

Originally Posted by PK1 (Post 99295)
Pushrods: you can use any brand you like. The magnum valve train doesn't use guide plates so they don't need to be hardened.

Ok so would i use stock 318LA length or 360mag length pushrods?
and what if I mill the heads 0.060?







10 Weeks till ship out :patriotic:

PK1 03-10-2013 02:21 PM

Negative.

You will need to measure for the pushrod. But its very easy. And then you can use what ever off the shelf fits.

If memory is correct the " kit " push rod length was 7.625 for a Mag headed LA hybrid.

Personally. I would measure. 5/16 pushrod checker from summit is about 15 bucks. You need one that measures at least 7.4-7.8. From there you can tape up the tool and send it to Smith Brother Push rods and they will make you 16 or measure yourself and get them from Summit.

You need Magnum Head bolts. Very cheap at www.rockauto.com

Search "net lash" on the forum. Couple folks on here have posted in depth "how to" for measuring PR Length.


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