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

[318willrun]

Every time I've put 360 heads on a 318, I've gained performance. I usually cut them about .040. No, I haven't cut the intake side of the head and I've not had a leak to this point. So far, I've always run them on stock short blocks. I've usually home ported them.

• In the future I'll be building another LA 318 roller block. I have a good set of 360 heads and a set of Magnum heads I could use to replace the 302 heads that are currently on the engine. This build will see some short block work.
• What do you think, Magnum heads or 360 heads (1.88/1.60) for best performance?

 

[oldkimmer]

Magnum heads will help a bit with comp. They also flow better than a LA head. Of course u will need to do a few changes to run the magnum heads. Kim

 

[66Valiant528]

I made the mistake of putting some 360 heads on a 318. The combustion chamber on the 360 head lowers the compression ratio on a 318. Car was a slug down low. Pulled fine up high but it was a mistake. At least rhat was my experience.

 

[318willrun]

Magnum heads will help a bit with comp. They also flow better than a LA head. Of course u will need to do a few changes to run the magnum heads. Kim

I made the mistake of putting some 360 heads on a 318. The combustion chamber on the 360 head lowers the compression ratio on a 318. Car was a slug down low. Pulled fine up high but it was a mistake. At least rhat was my experience.

I suspect on this build a piston change, maybe deck work, so I'll get the compression I want regardless of which head I chose.

 

[HankRearden]

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.

 

[318willrun]

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.

Cam will be replaced. I have what's needed to oil the magnum heads.

 

[318willrun]

This is more about which head will perform the best. Lets say if the compression is 10:to1 with both heads, which head will perform the best at, lets say .500 lift. I also have the ability to home port both heads, but I will NOT be installing larger valves as I believe either 1.88 or 1.92 will be more than ample supply for the 318

 

[HankRearden]

This is more about which head will perform the best. Lets say if the compression is 10:to1 with both heads, which head will perform the best at, lets say .500 lift. I also have the ability to home port both heads, but I will NOT be installing larger valves as I believe either 1.88 or 1.92 will be more than ample supply for the 318

I guess I was thinking just hop up. I wasn't thinking for a complete rebuild. If you are doing a complete rebuild for something that will see the strip it's hard to argue with the cheapie LA heads like Speedmaster.

If its a streetcar or you dont want buy heads I really think the magnum heads flow better.l

 

[318willrun]

I guess I was thinking just hop up. I wasn't thinking for a complete rebuild. If you are doing a complete rebuild for something that will see the strip it's hard to argue with the cheapie LA heads like Speedmaster.

If its a streetcar or you dont want buy heads I really think the magnum heads flow better.l

I won't be buying heads. I have factory LA 360 heads that I ran on my 360, and I have magnum heads also. Yes, it will see the strip.

 

[MOPAROFFICIAL]

Assuming this a stock 318 bottom end with a cam in it...If the 360 heads are bone stock 1.88 heads, it's pointless. What's to learn?
Smaller valves than the magnum
and bigger ports. That combo is a disaster. Less flow and a bigger hole.
Magnum- bigger valves, skinny stems, smaller chamber, better exh port, more rocker ratio.

A factory 2.02 j head would be a little more interesting since they flow with and better on the intake side. The magnum will still be armed with it's 1.6 ratio, smaller port volume/velocity,exh port flows more,closed chamber. All performance advantages in this case and most cases.You can make a LA better, but stock 1.88 as cast it's not.

Magnum head will be the better in this cid example

 

[318willrun]

I have just about everything of the bones of this build including both sets of heads, a few intakes to choose from, and the LA roller engine that used to be in DT, so a good foundation. I need better pistons, block work, and camshaft. Looking to make power to 6500 rpms, but the engine will decide ultimately the best place to shift. If it's 6200, or 6900, so be it.

 

[goldduster318]

I did a magnum head swap on a heavily worn 360 before my 340 was built. This thing was the absolute typical pistons a mile down the hole smog dog engine and for what it was it ran hard. Had the Summit k6901 cam and aftermarket valve springs and retainers and that's it. The engine was so worn I saved the heads after I had the 340 and we put the same ones on my friend's 318 magnum (the heads he got with it were cracked pretty bad), has a small Lunati cam and runs really hard.

The other thing I would say is the combustion must be a lot more efficient because both of the engines run really clean. Both had the same air gap manifold and a 600 holley.

I personally wouldn't run any OEM LA heads on anything anymore.

 

[PRH]

The main down side with regards to the above post is...... finding Oe Magnum heads that aren’t cracked.

 

[318willrun]

The main down side with regards to the above post is...... finding Oe Magnum heads that aren’t cracked.

In a sense, yes. However, most out there are cracked and the engines are running fine. I'm not saying cracks in the head are fine, but it doesn't seem to effect anything.

 

[MOPAROFFICIAL]

In a sense, yes. However, most out there are cracked and the engines are running fine. I'm not saying cracks in the head are fine, but it doesn't seem to effect anything.

Knowing and seeing them doesn't instill confidence though. Imagine being in the wrecking yard ,pulling some heads..inspecting them and saying to yourself..." I see cracks...im definitely spending the $170 bucks for'em now"

Most of the exhaust seats are hammered too. Finding any that are runnable 'as is' IS about impossible.
They were the ticket for a decade or so. It used to be you could find them less cracked and with fewer miles... but now they start to fall into common ground 'money wise' to make usable.
The seals fail, guides worn out... they dump oil through the intake guides and the plenum gasket when it goes multiple times in a magnums life unless you get the mahl steel gasket set ,like I did , or the Hughes plate. The chambers look like a coral reef of burnt oil peaks n crust on everything.

The death of EQ and RHS also killed the magnum craze. Trickflow,promax and even the cheap pos speed master friday deals solidifies the LA as the only choice.
The speed mast mags are good, if you know what to do with them... but no one is investing to find out other than me.. and cost wise...its 740 for set outside of the friday deal. ..then valve job, valves, locks, retainers, springs, port work like you would do to an RHS head and chamber work. They flat out work great after that..but Its a hard sell being a Chicon head that isnt a rhs or eq. Rhs have the dual exh pattern, extra ribbing, solid flat ends, thicker intake floors They 'rhs' weigh a lot more than a stock head. There's a few differnces.. just the finish of the chamber is so much nicer. You don't have to mess with it.
Takeaway is if they sold one without a valve job...then you could do one that's not set so low into the chamber....it'd be more like an rhs then...and just use the +.250 11/32 valves and have room for spring and rocker stud it accordingly for geometry. Done. No need to bring to 66 and mill it back to 60-62cc

 

[Bewy]

This is a case of......'if the stars align'.

Different heads, with different valve sizes, port size, combustion chamber shape, etc, etc, might work better with a change of engine capacity. Or might work worse..

 

[318willrun]

Knowing and seeing them doesn't instill confidence though. Imagine being in the wrecking yard ,pulling some heads..inspecting them and saying to yourself..." I see cracks...im definitely spending the $170 bucks for'em now"

Most of the exhaust seats are hammered too. Finding any that are runnable 'as is' IS about impossible.
They were the ticket for a decade or so. It used to be you could find them less cracked and with fewer miles... but now they start to fall into common ground 'money wise' to make usable.
The seals fail, guides worn out... they dump oil through the intake guides and the plenum gasket when it goes multiple times in a magnums life unless you get the mahl steel gasket set ,like I did , or the Hughes plate. The chambers look like a coral reef of burnt oil peaks n crust on everything.

The death of EQ and RHS also killed the magnum craze. Trickflow,promax and even the cheap pos speed master friday deals solidifies the LA as the only choice.
The speed mast mags are good, if you know what to do with them... but no one is investing to find out other than me.. and cost wise...its 740 for set outside of the friday deal. ..then valve job, valves, locks, retainers, springs, port work like you would do to an RHS head and chamber work. They flat out work great after that..but Its a hard sell being a Chicon head that isnt a rhs or eq. Rhs have the dual exh pattern, extra ribbing, solid flat ends, thicker intake floors They 'rhs' weigh a lot more than a stock head. There's a few differnces.. just the finish of the chamber is so much nicer. You don't have to mess with it.
Takeaway is if they sold one without a valve job...then you could do one that's not set so low into the chamber....it'd be more like an rhs then...and just use the +.250 11/32 valves and have room for spring and rocker stud it accordingly for geometry. Done. No need to bring to 66 and mill it back to 60-62cc

I haven't checked my magnum heads, they are still assembled. My LA 360 heads should be good pieces. they worked well on my 360.

 

[Ottmundr]

Every time I've put 360 heads on a 318, I've gained performance. I usually cut them about .040. No, I haven't cut the intake side of the head and I've not had a leak to this point. So far, I've always run them on stock short blocks. I've usually home ported them.

• In the future I'll be building another LA 318 roller block. I have a good set of 360 heads and a set of Magnum heads I could use to replace the 302 heads that are currently on the engine. This build will see some short block work.
• What do you think, Magnum heads or 360 heads (1.88/1.60) for best performance?

I would rather see the 360LA heads, but I bet the magnum heads would perform better.

• rocker shaft
• I got some 308 heads
• I don't have a magnum or magnum heads
• The newfangled technology of the Magnum engine just does not appeal to me.

 

[dirty white boy]

Every time I've put 360 heads on a 318, I've gained performance. I usually cut them about .040. No, I haven't cut the intake side of the head and I've not had a leak to this point. So far, I've always run them on stock short blocks. I've usually home ported them.

• In the future I'll be building another LA 318 roller block. I have a good set of 360 heads and a set of Magnum heads I could use to replace the 302 heads that are currently on the engine. This build will see some short block work.
• What do you think, Magnum heads or 360 heads (1.88/1.60) for best performance?

do all 3!! port them 302s with 1.88s and 1.60s! and have a 3 way shoot out and post up your results to show what each will do on a 318 and maybe clear up all these dern 318 head threads so we can go back to debating best 318 cams like we use too!!

 

[318willrun]

do all 3!! port them 302s with 1.88s and 1.60s! and have a 3 way shoot out and post up your results to show what each will do on a 318 and maybe clear up all these dern 318 head threads so we can go back to debating best 318 cams like we use too!!

To be fair, I'd either run all 3 stock or all 3 fully worked over. Unfortunately, while it would be interesting, the time it would consume, and financing will not allow me to do this kind of test. I'm overloaded with projects...lol

 

[dirty white boy]

To be fair, I'd either run all 3 stock or all 3 fully worked over. Unfortunately, while it would be interesting, the time it would consume, and financing will not allow me to do this kind of test. I'm overloaded with projects...lol

im all for stock test before "worked" test,..lol you owe it to your 318WR legacy,..besides think bout the youtube hits youll get,..and make the tell all thread a sticky on the SBM forum!!

 

[318willrun]

im all for stock test before "worked" test,..lol you owe it to your 318WR legacy,..besides think bout the youtube hits youll get,..and make the tell all thread a sticky on the SBM forum!!

LOL.... Well, this build really isn't to "prove" anything. Actually, I can't remember the last time I built anything to "prove" something. I may do something just to "see" for myself. But IF I was to do a test, it wouldn't convince one person that was a "believer" in a certain way of doing things. To them the test would be flawed in many ways thus the test would be nullified. I just share some of what I'm doing on my cars on youtube, not specifically look'n for "hits" LOL

 

[318willrun]

This is the roller 318 I'll be using

since been pulled from the truck and on the engine stand

 

[dartfreak75]

What all oil modifications have to be done to use magnum heads? Is it as simple as using magnum pushrods with the oil hole thru the pushrod?

 

[318willrun]

What all oil modifications have to be done to use magnum heads? Is it as simple as using magnum pushrods with the oil hole thru the pushrod?

oil through pushrods and lifters.