360 heads on a LA 318 vs Magnum heads on a LA 318

[Ted265]

I might. My 302's went 240's with 140 cc port so it shouldn't be too hard.

What did yours flow?

I would be interested to see how they turn out.
I never had those heads on a flow bench. 1.78/1.5" valves but worked quite well on both engines I ran them on.

 

[volaredon]

I've done multiple milled 360 to 318 head swaps for street cars and pickups. Today,for me it would depend on if were swapping the cam and lifters. if I didn't want to change cam and lifters to oil magnum valve train I'd use 360 heads. If i were changing cam and lifters I would use magnum heads.

Don't have to change cam if you don't want to just the lifters. Ok to put new lifters on a flat tappet cam but not ok to run used lifters on a new cam.
Lifters just gotta have the pisser hole to feed the pushrods with oil. And on the 3 magnum heads to LA Block jobs I've been in on 7.650 seems to be the magic number on pushrods. The MP conversion pushrods are 7.625 and each time I've tried them they've been too short, wind up with lifter clatter like you'd hear on a /6.
There is a ford 351W application that uses that length which were the pushrods I used, so being an off the shelf application instead of something custom also means the price of these pushrods are reasonable.

 

[volaredon]

There were 2 different casting numbers on most all magnum heads, from what I remember they are supposed to be identical and totally interchangeable, mixing and matching is not supposed to be a problem. From what I remember they were cast in 2 different plants and that was how they were able to tell which plant they came from.

 

[moparmandan]

There were 2 different casting numbers on most all magnum heads, from what I remember they are supposed to be identical and totally interchangeable, mixing and matching is not supposed to be a problem. From what I remember they were cast in 2 different plants and that was how they were able to tell which plant they came from.

Did you see post #73? Tends to be in line with what you're saying.

 

[volaredon]

Nope I didn't read thru the whole thing yet sorry.

 

[MOPAROFFICIAL]

I used to think this also. Then read this at Moparchat. Any validity to this?

"Magnum Heads (5.2 vs. 5.9)

There ARE actually two different castings for production Magnum heads, Apparently the 5.9 heads made in Mexico (machined at Toluca) and the 5.2 head made in the USA (machined at Mound RD). I donÂ’t know when these changes were made or if they have been there since the Magnum engines were introduced.
The major differences are listed below:

1) The intake port volume is 10cc larger on the 5.9 head (about 162-163cc).
2) The intake port is about .100 taller on the 5.9 head.
3) The valve guide boss in the intake looks smaller on the 5.9 head.
4) There are several minor differences in the physical appearance of the castings, most obvious is a little “hump” between the exhaust ports on the 5.2 head, this “hump” is not seen on the 5.9 casting.

SPECIFICATIONS

5.9 CASTING
Casting # 53006671
Machined Part Number 53021139
Intake Port Volume 162-3cc
Castings made at Cifunsa in Mexico/Machined at Toluca
Included on all production 5.9 engines built at Toluca
Mopar never sold this cylinder head separately as a service part
Mopar Performance Magnum crate motors are equipped with this casting on all Arrow Racing built/reworked engines
Mopar Performance crate motors now built/reworked by Cummins include these heads (since the Mound Road heads are no longer available) Earlier motors built/reworked by Cummins up to mid 2001 included Mound Road heads.
Mopar Performance Cylinder Heads P4876257 and P5007086 are now made from this casting (but there may be mixed stock in the depots since the 5.2 head was used up until the Mound Road Plant built-out).

5.2 CASTING
Casting # 53020466
Machined Part Number 53021137
Intake Port Volume 152-3cc
Castings made at New Haven, MI/Machined at Mound Road Engine Plant
Included on all production 5.2 engines built at Mound Road Engine Plant
Mopar sold this casting at dealers to service both 5.2 and 5.9 engines from ’92 to ‘01
Mopar now sells this a Re-Man cylinder head since these heads are no longer available from Mound Road.
Mopar Performance Crate Motors included these heads when Cummins started building them (up to mid 2001).
This head is no longer available from Mopar and has been “ruled” to a Re-Man head R5852426 (since mid 2001)
Mopar Performance Cylinder Head P4876256, when it was available was the same as this cylinder head."

I had heard the early 5.2 mag had a smaller port head..but that it went out and they started using the same head for each...that said... I have never seen a 162 cc magnum head on any 5.9 , or anywhere else for that matter. Have you? Has anyone posted a picture and or a vid doing port volume check? I have seen some different looking heads in the aftermarket replacement sector...but they arent factory castings...so what am I comparing ... speed master for instance, sent me 2 diff castings. One looked taller inside..had a tighter pinch too though.. guide was taller. Idk what's going on with them or who is casting them. Stock 2.02 j heads measured 155cc and 160cc for 1.88. Why the seemingly backwards sizing? Because the factory 2.02 has a huge tulip that eats up bowl volume...and is heavy. The 1.88 hardly has any tulip in comparison. The valve jobs were also not bowl hogging cuts on the bigger valve. I find it hard to believe they were putting out 162-163 cc magnum heads if smaller port volume had anything to do with their efficiency. That's just my findings.

 

[Mopar44134]

First time ive heard there is a difference between magnum heads.

As for identifying cracks in the heads. When i pulled the valves, i usually spray down the ports with brake or carb cleaner. I read somewhere to let them soak and then heat them up with a propane torch. The cleaner will boil out. On the first head i checked, the carb cleaner evaporated, but since the crack was still filled with cleaner, it left an identifiable line.

I was doing a head gasket on my brothers boat... 4 cylinder. I figured, lets clean up the ports with a grinder before sending them out to be milled. Sprayed them down...those were cracked.

 

[HankRearden]

Don't have to change cam if you don't want to just the lifters. Ok to put new lifters on a flat tappet cam but not ok to run used lifters on a new cam.
Lifters just gotta have the pisser hole to feed the pushrods with oil. And on the 3 magnum heads to LA Block jobs I've been in on 7.650 seems to be the magic number on pushrods. The MP conversion pushrods are 7.625 and each time I've tried them they've been too short, wind up with lifter clatter like you'd hear on a /6.
There is a ford 351W application that uses that length which were the pushrods I used, so being an off the shelf application instead of something custom also means the price of these pushrods are reasonable.

I'm surprised you have had luck with new lifters on a used flat tappet cam. Back when I had my engine classes they told us never to try it. That does open up some possibilities for low buck hop ups.

 

[goldduster318]

If it helps, here are some pictures of the 53020466 Magnum heads I had run on my 360 and are now on my friend's 71 Demon 318 Magnum: