school me on a 5.9 magnum motor.

-
abodyjoe

abodyjoe

Well-Known Member
Joined
May 22, 2004
Messages
24,398
Reaction score
13,769
Location
Berlin,N.J. 08009
what inter changes between a LA and magnum small block.

stuff like timing chain, timing chain cover, oil pump and oil pan. distributor ? will 340 exhaust manifolds fit a magnum head? i know the intake is different. are the LA accessories able to work on the magnum?
 
abodyjoe said:
what inter changes between a LA and magnum small block.

stuff like timing chain, timing chain cover, oil pump and oil pan. distributor ? will 340 exhaust manifolds fit a magnum head? i know the intake is different. are the LA accessories able to work on the magnum?
Click to expand...
ive used a couple magnum 5.9s. An LA 360 car pan works. I used an LA timing set. I did use the magnum accessories to get the serp belt set up and higher amperage alternator.I used la headers on magnum heads and magnum headers on la heads. no leaks.
 
Biggest difference is shaft rockers on LA and pedestal style on magnum. Oil through pushrods on magnum and deck/head oiling on LA. Basically every part between the 2 series will interchange. You just have to be mindful of what you’re changing and the steps you need to take to make it work.
 
Turbosmblk said:
Biggest difference is shaft rockers on LA and pedestal style on magnum. Oil through pushrods on magnum and deck/head oiling on LA. Basically every part between the 2 series will interchange. You just have to be mindful of what you’re changing and the steps you need to take to make it work.
Click to expand...

all id be doing is a basic rebuild. i have new LA oil pump and timing chain in the basement. have all the LA brackets and accessories on the car already. so if its just a matter of a rebuild and buying a magnum flexplate and intake it sounds like I'm good. oh and that cam snout extension to run a mechanical fuel pump. then i just have to hope the exhaust manifolds fit properly. didn't really want headers on the car but if i had to i guess I'd do it.
 
My TTI step headers have Magnum port shape. I was told at the time that only way they come. So the header flange hangs into each of the 4 LA corners ports, the two front and two rear ports. But its lower corner so impact to flow not as bad. I had a welder add a bead to header flange to increase flange to gasket surface so easier for gasket to seal.

Point is LA and Magnum exhaust ports are different but close. You might have to use some high end squishy header gaskets to get 340 manifolds to seal. Or maybe add JB weld around outside edge of front and rear ports to provide a gasket surface. I believe the 4 middle ports match its the 4 outside on lower corner on each of those 4 thats needs looking into.

Magnum heads are prone to cracking so look out for that.

Magnum heads flow great and factory roller cam decent compression. 360 Magnum very nice starting point just freshen up cam with matching valve springs make some good power.
 
340sFastback said:
Some info in here on running 340 manifolds with magnum heads:

340 manifolds and Magnum heads
Click to expand...

Good find. I run some 340 manifolds on my R/T heads and had to get adapter cut like mentioned in that post.

Some of what it comes down to is how the heads were cast. When I was putting my motor together, a buddy of mine had a set of Magnum heads on the bench and the material around the port went all the way to the bottom of the head. So I went forward thinking there was plenty of material to seal the manifolds. Then I went to bolt them onto my heads and saw that my ports had just enough material to seal the Magnum exhaust, but not enough for the 340 manifolds. So I had to scrabble and get some adapter cut.

Pretty sure I have posted pictures of the issue and of the adapters on here before. And I still have file, you could get someone like SendCutSend to make a set if you wanted.
 
abodyjoe said:
what inter changes between a LA and magnum small block.

stuff like timing chain, timing chain cover, oil pump and oil pan. distributor ? will 340 exhaust manifolds fit a magnum head? i know the intake is different. are the LA accessories able to work on the magnum?
Click to expand...

Here's what a 360 Magnum looks like dressed like a "day 2" 340.

I used all LA front, including alternator, all brackets, power steering ,pulleys, valve covers etc.

One ***** was to get the bypass hose to fit. Also getting a lower rad hose that worked properly.

Let me know if I can help further.


1709642207248.png






1709642397415.png
 
abodyjoe said:
what was the issue with those two things?
Click to expand...
Hey abodyjoe,

The bypass hose nipple for the la is orientated differently out of the intake I used. The La nipple is on an angle that lines up better with the water pump. The Magnum is straight making it difficult to bend the preformed bypass hose.

The LA lower water pump hose is shorter. I finally found one at nappa that worked. I'll see if I can find the part number for you.
 
Super-Cuda said:
Hey abodyjoe,

The bypass hose nipple for the la is orientated differently out of the intake I used. The La nipple is on an angle that lines up better with the water pump. The Magnum is straight making it difficult to bend the preformed bypass hose.

The LA lower water pump hose is shorter. I finally found one at nappa that worked. I'll see if I can find the part number for you.
Click to expand...
I also need the hose # , thanks
 
If a Magnum engine is dressed out with LA timing cover and water pump the lower hose would be whatever correct part number is for the application you set it up to be.

If the car has a correct size and style radiator with right side water outlet it will need a later style right side water pump and lower hose to match.

If the car has a correct size and style radiator with left side water outlet it will need an early style left side inlet water pump and lower hose to match.
 
Hughes offers a service to drill tap Magnum heads to accept an LA intake manifold. So that and using an LA water pump avoids a bypass hose issue. And it further disguises it as an LA engine.
 
Last edited:
Bobzilla said:
If a Magnum engine is dressed out with LA timing cover and water pump the lower hose would be whatever correct part number is for the application you set it up to be.

If the car has a correct size and style radiator with right side water outlet it will need a later style right side water pump and lower hose to match.

If the car has a correct size and style radiator with left side water outlet it will need an early style left side inlet water pump and lower hose to match.
Click to expand...
This could be indeed accurate.

I used an RMS suspension upgrade that could have moved the motor just enough that the hose wouldn't fit.

Rad has stock outlet positions and factory aluminum water pump.
 
Super-Cuda said:
Hey abodyjoe,

The bypass hose nipple for the la is orientated differently out of the intake I used. The La nipple is on an angle that lines up better with the water pump. The Magnum is straight making it difficult to bend the preformed bypass hose.

The LA lower water pump hose is shorter. I finally found one at nappa that worked. I'll see if I can find the part number for you.
Click to expand...

awesome thanks. what are you using for a flexplate? i's like to run a SFI one.. i keep looking them up and coming up with LA ones..
 
340sFastback said:
Hughes offers a service to drill tap Magnum heads to accept an LA intake manifold. So that and using an LA water pump avoids a bypass hose issue. And it further disguises it as an LA engine.
Click to expand...

that would be nice.. wonder what their turn around time is.. shipping may be expensive too..
 
You must log in or register to reply here.
-

Back
Top