Lookin at a set of RHS LAX heads for a possible Mopar project I may do. I know nothing about. What do I need to know and or look out for? Thanks.
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RHS LAX heads.....
- Thread starter RustyRatRod
- Start date
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DieWilde13
Well-Known Member
You need different Headbolts for them. The Std. Bolts doesn´t fit.
Otherwise they fit good.
Otherwise they fit good.
I've got a set on the 318 for my Dart. I will say this about them, they are HEAVY. As in, significantly heavier than a stock set of iron heads.
Other than that, the set I have CC'd at 63cc's, they're advertised at 62. Because they're on a 318 I just went with the 1.92/1.62 valves. Rocker geometry checked out fine with a set of Crane ductile iron adjustable rockers I'm going to be using on them. I'm using a set of custom Smith Bros push rods for them, I don't recall off the top of my head what the length ended up being. Although I had the 318 zero decked anyway so that might not help, and it was a pretty good cut as the banks weren't even the same height to start. Haven't run it yet, so, I'm not any help there. I wasn't looking for crazy power, I just decided that for what it costs to refurbish a set of heads I was better off with these, couldn't see spending to do valves, guides, seals, milling, etc on the stock set of 318 heads I had. If it makes 300-320 hp I'll be happy, this is supposed to be the tame, easy to drive car to counter my Duster.
Other than that, the set I have CC'd at 63cc's, they're advertised at 62. Because they're on a 318 I just went with the 1.92/1.62 valves. Rocker geometry checked out fine with a set of Crane ductile iron adjustable rockers I'm going to be using on them. I'm using a set of custom Smith Bros push rods for them, I don't recall off the top of my head what the length ended up being. Although I had the 318 zero decked anyway so that might not help, and it was a pretty good cut as the banks weren't even the same height to start. Haven't run it yet, so, I'm not any help there. I wasn't looking for crazy power, I just decided that for what it costs to refurbish a set of heads I was better off with these, couldn't see spending to do valves, guides, seals, milling, etc on the stock set of 318 heads I had. If it makes 300-320 hp I'll be happy, this is supposed to be the tame, easy to drive car to counter my Duster.
360duster
Well-Known Member
i use them with good results. Depending on the application there is a limit in valve lift....in stock form around .525" as far as i know. Brian @ Imm does sell these in different versions.
Michael
Michael
Those I was getting back around 2010 had very thin exhaust ports in cylinder 7 or 2, so porting there should be done with extreme caution. Some of the pushrod holes were very thin on the intake port. Cody would touch them with the burr and they would immediately break out.
HEAVY? OH BOY YEAH!
HEAVY? OH BOY YEAH!
little story with these and a comp keeper..... 
Mopar RHS Indy Cylinder Heads Dodge Plymouth Small Block 318, 340, 360 LA Heads
I myself think a good set of 360 heads (ones that didn't need valve guides etc etc) that were home ported and milled would fill the need for most applications, especially if 2.02's were installed with a good performance valve job.
Mopar RHS Indy Cylinder Heads Dodge Plymouth Small Block 318, 340, 360 LA Heads
I myself think a good set of 360 heads (ones that didn't need valve guides etc etc) that were home ported and milled would fill the need for most applications, especially if 2.02's were installed with a good performance valve job.
Ironmike
Well-Known Member
I had mine cnc ported. They didn't touch the exhaust side. My machinist thought that was odd. Engine made 562 HP, I thought it shoulda made more. Machinist said that's about all they're capable of due to the exhaust ports. Something about " floor design and practically no short turn". They actually flowed pretty close to the advertised numbers but he thought velocity was "ok".
.640 lift LunatI roller this time. Ran a .681/.688 Comp 2 years ago. Perfect geometry with Hughes rockers and Smith 3/8 rods. All in all I think they're a darn good head albeit with limits.
Oh yeah. 63 pounds a piece. I know. I shipped them clear across the country. Yikes!
Good luck with them. I think you'll like em.
.640 lift LunatI roller this time. Ran a .681/.688 Comp 2 years ago. Perfect geometry with Hughes rockers and Smith 3/8 rods. All in all I think they're a darn good head albeit with limits.
Oh yeah. 63 pounds a piece. I know. I shipped them clear across the country. Yikes!
Good luck with them. I think you'll like em.
little story with these and a comp keeper.....
Mopar RHS Indy Cylinder Heads Dodge Plymouth Small Block 318, 340, 360 LA Heads
I myself think a good set of 360 heads (ones that didn't need valve guides etc etc) that were home ported and milled would fill the need for most applications, especially if 2.02's were installed with a good performance valve job.
That's what I am trying to weigh out. Yall all know how I like rebuilding stuff to be good again and how cheap I am. lol Thanks. yall. Feel free to keep it coming.
yellow rose
Overnight Sensation
I detest that chamber. I know Dave Hughes thinks is all that, but I'd rather have a regular open chamber.
In fact, when I quit racing, I was working on a program to machine the worthless W-5 chamber to P-car dimensions.
Just my 2 cents, adjusted for inflation, is now a negative number.
Oh wait, I forgot, there is no inflation. Sorry for my ignorance.
In fact, when I quit racing, I was working on a program to machine the worthless W-5 chamber to P-car dimensions.
Just my 2 cents, adjusted for inflation, is now a negative number.
Oh wait, I forgot, there is no inflation. Sorry for my ignorance.
IT'S NOT A RACE HEAD! It was made to be a stock replacement head. The head flows better OOTB than the factory iron heads. You can force it to make some real horsepower. The first time I got my hands on one was at the 2009 Amsoil/Mopar Muscle Magazine Engine Challenge. Both Cody and I thought, "Why did they make a stupid intake port like that?" There was a big boss cast into the port roof to support the Magnum rocker stud. And yes the boss is in both the LA and Magnum heads because they are the exact same castings (or they were in 2010). The exhaust port is far superior to the factory Mopar castings. When we tried back in 2010 we got 296 cfm intake and 286 cfm exhaust @ .600" lift. But it isn't too hard to get 236 cfm exhaust, which is 100 cfm more than the stock Mopar factory iron head. We've got a set of fairly exotic rocker arm LAX style RHS heads here that flow 264 @ .500" and 280 @ .600" with a 1.94" intake. We are going to put in a 2.055 intake, reassemble the heads and look for a good small block to put the heads on for some dyno testing.
So did you find removing/porting the head to eliminate the support from the intake port since it's just there to support the magnum rocker studs made much of a difference in port flow?
yellow rose
Overnight Sensation
Who is claiming it's a race head? I didn't see where that was written. It is what it is. A replacement head. With a crap combustion chamber.
I'm sorry that you took it personal. Try not to be so sensitive, everything I write isn't about you. I was replying to the thread in general and giving my opinion on the head. You have some good ideas Rose and some opinions that I really do agree with. Just.......not always.....
yellow rose
Overnight Sensation
Thanks for adding to the discussion. So you disagree with me? Who cares? I call junk what it is. Funny thing is, when a guy buys junk, he wants his buddies and everyone he can influence to buy junk so he don't look the fool.
I have spent hours with Dave Hughes in discussions on combustion chambers. We agreed to disagree. I have my understanding of combustion chamber geometry, how a piston at TDC completes it and how the valve job is dictated by it.
Since you probably can't address any of these, I'll say it again, I think that chamber is junk. Most like it because they think it makes compression more easily. Maybe so, but the compromises in geometry are more than I want to deal with. Look at a W-5 chamber. If you are not willing to think outside the box just on the valve job, a W-2 will beat it up. Which, ironically is what happened when the head was first released. Thankfully, I ran into a guy running Comp and warned me of the pitfalls. BTW, he was a record holding builder and was involved in the development of the W-7 head.
So have your pet theories and love affairs with GM like crap. I have some stud mounted rockers for sale.
Good gawd.
yellow rose
Overnight Sensation
That goes both ways. You CAPPED it, not me. Was just trying to clarify because I thought I missed something.
Six years ago man, it's hard to remember. They are up in boxes on a dusty shelf and I can't remember exactly how the flow development went. We used the LAX head and put Chevy stud mounted rockers on it. Did we leave some of the boss in there? I think so because we got so far and there didn't seem to be any more flow gain. But again, these were only using a 1.940 intake because they were going on a big bore 292?/273. We have a LAX flowing over 300 cfm but it is in a box on the closet floor back at the house. Been there unopened since 2010.
rmchrgr
Skate And Destroy
I like mine. 500 HP from a real basic 416 which is 1.2hp/cube. Not bad for an old-school, iron headed small block with a FT cam. Torque is unbelievable in this thing, does not go under 430 ft lbs. between 3,800 - 5,800 rpm. I will be honest, I thought it would make a little more, like 525 but I made some choices elsewhere that had an effect on the overall HP so it is what it is. 500 hp is nothing to sneeze at though, should get me where I want to be with my car.
IMM CNC ported RHS heads, cam spec'd by Brian, 251/259 @ .50" solid FT with Hughes 1.6 rockers which comes out to just under .6" lift. Mine are cut for 2.02 valves.
Like said above, good rocker geometry, no shims needed. I did the whole ink on the valve tip thing too, they were dead nuts.
I didn't think these heads were any heavier than your standard factory iron casting. I never weighed them but my old W2s seemed way heavier. I believe they have thicker deck surfaces and wider valve cover rails if that means anything to ya.
The one issue I had was with the dowel holes. Took a little massaging and a couple whacks with a dead blow hammer to get them to seat all the way but it wasn't a huge deal.
Decent pieces for the money. Of course there are better heads out there but the price reflects the difference. These would be a good choice for anything under 600 hp. If you are looking to make more power, it would be best to look elsewhere. 562 HP from these is making some power.
Didn't think these were even being made any more but I could be wrong. I got mine several years back.
IMM CNC ported RHS heads, cam spec'd by Brian, 251/259 @ .50" solid FT with Hughes 1.6 rockers which comes out to just under .6" lift. Mine are cut for 2.02 valves.
Like said above, good rocker geometry, no shims needed. I did the whole ink on the valve tip thing too, they were dead nuts.
I didn't think these heads were any heavier than your standard factory iron casting. I never weighed them but my old W2s seemed way heavier. I believe they have thicker deck surfaces and wider valve cover rails if that means anything to ya.
The one issue I had was with the dowel holes. Took a little massaging and a couple whacks with a dead blow hammer to get them to seat all the way but it wasn't a huge deal.
Decent pieces for the money. Of course there are better heads out there but the price reflects the difference. These would be a good choice for anything under 600 hp. If you are looking to make more power, it would be best to look elsewhere. 562 HP from these is making some power.
Didn't think these were even being made any more but I could be wrong. I got mine several years back.
moper
Well-Known Member
Not sure what you're building RRR, but if it's a milder package I'd look at the EQ Magnums. MUCH lighter, similar out of the box performance, and a lot cheaper. Both come as bare castings - so rocker geometry may vary depending on if the shop does a valve job or not.
As was said - magnum based heads have issues with lift. So mild cams they works well. Going larger means more dilligence, or a different head.
As was said - magnum based heads have issues with lift. So mild cams they works well. Going larger means more dilligence, or a different head.
I am not sure what I am building either. Yet.
MopaR&D
Nerd Member
Would you mind explaining your rationale on that? No sarcasm I'm honestly curious.
Can we refrain from the dick wagging contest? I just asked a simple question. Thanks for your input other than that. It is much appreciated.
yellow rose
Overnight Sensation
I DID add to the discussion. Those are my heads in post #3, thanks very much. As well as the actual as delivered chamber volume on the set that I got, rocker geometry info with Crane ductile rockers, and some eye candy pictures as well. Maybe it's not much, but it's actual technical information.
What have you added? You don't like them, they're junk, no specific information at all, you disagree with Dave Hughes. Sounds familiar. Hence the broken record. And then you say you're not going to get into actually discussing it because I won't understand. Sir, I hold a degree in Aerospace engineering. There is nothing you can say that I won't understand if it relates to something mechanical, and don't even get me started on fluid dynamics.
As for junk, no, they are not. No, they aren't W-2 heads either. But they're not supposed to be, that's why you can buy a pair of them complete for a grand. They're a step up from stock heads. They add compression, flow better than stock heads right out of the box without need for extensive porting or machining, and allow for a moderate cam without modification. In other words, they're a great head for mild to moderate builds and won't bust your budget like a set of W-2's and all the fancy crap you need to go with most of those. The LA-X heads can use all the stock rocker hardware, just like the shaft-mounted crane ductile's that are going on mine. And LA intakes, standard LA headers, pretty much everything is standard LA except for the head bolts.
I don't care if anyone else buys them, I'm not trying to push them on anyone, I just posted what I know. I don't have stock in RHS or Indy. I probably won't even buy another set myself. They were the right choice for the application I was building, just a boring 300-ish hp 318 with good street manners that I can put a 100k miles on with nothing but oil changes and tune ups. And I said that right up front. If I didn't think they would do what I wanted them to, or if I thought they had real problems I WOULDN'T tell anyone else to use them, because I'm fine with owning my mistakes. If I thought they were junk I'd have told Rob "run away" when he asked about them. I don't need anyone else to approve of my decisions for me to enjoy my cars, that's why I don't go to car shows and why I only own pre-75 Mopars that I drive every day. I like driving them, that's it.
IQ52 posted great info on the heads. They're not perfect, they have their issues and shortcomings as he pointed out, but they're capable heads if you're using them in the right application. And they can be really capable heads with the right work, although for that application there are better choices out there. That's helpful, and that's adding to the discussion. Engine builders all have their theories, Brian has done pretty darn well building engines with his and he does it for a living.
Not everything is a full race drag car. What works great on my 13-second-and-plenty-of-change daily driver won't work on a bracket car. And most of what works great on a bracket car won't work for crap on a daily driver either.
Rob, I apologize for derailing your thread with this one. Hopefully my first post was some kind of benefit to you, I'm outta here.
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o1heavy
1974 dart sport
Can you give more details on your combo. Intake,compression , solid roller ? Thanks
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