Slant Six head swap?

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SpriceyStuff

SpriceyStuff

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Hey guys. I got a (maybe not so)crazy idea. I have a late model slant six in my car (77), and I have an earlier model engine laying around. One thing I hate about the new cylinder head design is the spark plug arrangement. I find it harder to work with with the plugs all facing at an angle instead of perpendicular to the head. But I also don’t like that the new heads are open chamber and low compression. Has anyone here tried swapping an older head onto a newer motor and know if the bolts and holes will line up or if there will be any other issues like water jackets and oil galleys not lining up? I like the idea of boosting compression but I don’t want to just haphazardly slap a different head on there and have it be catastrophic to the engine…
 
Your older head will swap over to your 77 motor just fine. However, I don't think you are going to get much of an increase in compression with the older head. Slants are notorious for low compression from the factory. The only way to verify this is to CC both heads, see how for down the hole your piston is at TDC, and do the math for each head. I suspect you will need to shave the head to accomplish much in the compression arena.
 
halfafish said:
Your older head will swap over to your 77 motor just fine. However, I don't think you are going to get much of an increase in compression with the older head. Slants are notorious for low compression from the factory. The only way to verify this is to CC both heads, see how for down the hole your piston is at TDC, and do the math for each head. I suspect you will need to shave the head to accomplish much in the compression arena.
Click to expand...

oh man. I was hoping the difference between open and closed chamber heads would be big enough to feel a difference. But swapping a head is a fair bit of work to go through. But if it’s not worth it then I won’t bother
 
SpriceyStuff said:
Hey guys. I got a (maybe not so)crazy idea. I have a late model slant six in my car (77), and I have an earlier model engine laying around. One thing I hate about the new cylinder head design is the spark plug arrangement. I find it harder to work with with the plugs all facing at an angle instead of perpendicular to the head. But I also don’t like that the new heads are open chamber and low compression. Has anyone here tried swapping an older head onto a newer motor and know if the bolts and holes will line up or if there will be any other issues like water jackets and oil galleys not lining up? I like the idea of boosting compression but I don’t want to just haphazardly slap a different head on there and have it be catastrophic to the engine…
Click to expand...

The actual swap itself is no problem, it will bolt on. Speaking from personal experience, bolting a new head with higher compression onto an old warn motor is not a good idea. It is the only time I ever have shot a rod through the block was after I shaved my head .100 and swapped it on my 60,000 original miles slant. I think it was just too much for the old motor. I’m going to be pulling the rebuilt slant six out of my car, has about 30,000 miles on the rebuild. 1974 block, 1974 head all the good stuff. The carb needs to be gone through , modern gas is killing all the seals after three years. It’s yours for free if you can pick it up in Lacey.
 
Hello, when you say plugs tilting at an angle, you don't mean fore and aft do you?
I know the "peanut" head plug tilt, but on the same angle as the drool tube heads.
Just no tube.
 
I'd have to look, but I thought the plugs pointed the same on both the 'peanut' heads and the 'drool tube' heads. And, I agree, you will see little (if any) compression difference. Most stock slant heads are in the 55 +/- 5 cc range, early or late heads, so swapping heads would be a crap shoot for little, if any gain. The only practical way to increase compression is new pistons or head shave/block decking. You better do the math to make sure you get what you want.
jus sayin....
 
I was looking at some old pics of some heads I've done over the years and came across what I swear is a / head and the plug was a hair toward the ex, it was a hyd/peanut head late 77
 
SpriceyStuff said:
Hey guys. I got a (maybe not so)crazy idea. I have a late model slant six in my car (77), and I have an earlier model engine laying around. One thing I hate about the new cylinder head design is the spark plug arrangement. I find it harder to work with with the plugs all facing at an angle instead of perpendicular to the head. But I also don’t like that the new heads are open chamber and low compression. Has anyone here tried swapping an older head onto a newer motor and know if the bolts and holes will line up or if there will be any other issues like water jackets and oil galleys not lining up? I like the idea of boosting compression but I don’t want to just haphazardly slap a different head on there and have it be catastrophic to the engine…
Click to expand...
You can do it, but you actually have your information backwards. The earlier heads were inferior. There is no closed chamber slant six head, only what Chrysler called the "revised" head. Read this. It will explain it. You will be backing up putting the early head on.
Revised SL6 Combustion Chamber
 
Hyper_pak said:
Hello, when you say plugs tilting at an angle, you don't mean fore and aft do you?
I know the "peanut" head plug tilt, but on the same angle as the drool tube heads.
Just no tube.
Click to expand...
Correct. There's not much if any difference at all between the plug angle. Plus, the later heads are the "better" chambers anyway.
 
I've only ever heard of 2, close chambered heads on a /6. RRR has one, Doug Dutra has the other.
I have both peanut heads and a drool tube head here off of engines. No difference in combustion chambers on the ones I have, among them. All of mine are 74 and newer. 74 was last year for drool tube heads

There's an article on the /6 site about this, there was a modification on heads' combustion chambers after 1968 vs those before, and the after 68 heads were deemed better/// but when they went to the peanut heads, that part didn't change.
I don't think there's a difference in spark plug angle anywhere along the lines.
One BIG difference between drool tube and peanut heads is that with a peanut head you eliminate 6 certain oil leaks, those being around each drool tube.my last build was a 74 225, and I put a77 or 78 peanut head onto it for that reason. I still have that original '74 head here in the garage.

Also back when my dad had his 82 gran fury with it's /6 and he ended up with a cracked head, I put on a 60s head to get him going again using what I had laying around. Valve cover was different 81 and newer vs any /6 before then and I had to drill out the last hole in the rocker shaft but that was it. Direct swap/bolt on, besides that.

I see others chimed in while I was, and beat me to most of what I said here.
 
volaredon said:
I've only ever heard of 2, close chambered heads on a /6. RRR has one, Doug Dutra has the other.
I have both peanut heads and a drool tube head here off of engines. No difference in combustion chambers on the ones I have, among them. All of mine are 74 and newer. 74 was last year for drool tube heads

There's an article on the /6 site about this, there was a modification on heads' combustion chambers after 1968 vs those before, and the after 68 heads were deemed better/// but when they went to the peanut heads, that part didn't change.
I don't think there's a difference in spark plug angle anywhere along the lines.
One BIG difference between drool tube and peanut heads is that with a peanut head you eliminate 6 certain oil leaks, those being around each drool tube.my last build was a 74 225, and I put a77 or 78 peanut head onto it for that reason. I still have that original '74 head here in the garage.

Also back when my dad had his 82 gran fury with it's /6 and he ended up with a cracked head, I put on a 60s head to get him going again using what I had laying around. Valve cover was different 81 and newer vs any /6 before then and I had to drill out the last hole in the rocker shaft but that was it. Direct swap/bolt on, besides that.

I see others chimed in while I was, and beat me to most of what I said here.
Click to expand...

Yeah, I kinda fibbed when I said there were no closed chamber heads. Doug said there were like five cast, but the one he has and mine are the only two he said he's seen. For all practical purposes, there were none. None were ever supposed to make production, but evidently the one I have somehow did.
 
MOPAROFFICIAL said:
I was looking at some old pics of some heads I've done over the years and came across what I swear is a / head and the plug was a hair toward the ex, it was a hyd/peanut head late 77
Click to expand...
Could be, I've not looked very closely comparing the two.
 
RustyRatRod said:
Yeah, I kinda fibbed when I said there were no closed chamber heads. Doug said there were like five cast, but the one he has and mine are the only two he said he's seen. For all practical purposes, there were none. None were ever supposed to make production, but evidently the one I have somehow did.
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Was it the Argentina heads that were or something? For some reason that is in my mind...
 
Argentina
SA 00.jpg
SA 05.jpg
 
RRR, that is a beautiful head!
For reference here is the revised chamber.
Your exhaust wall is a lot different.
The plugs do look canted.
BR Revised Chamber.JPG
 
RustyRatRod said:
No, this one is different than the Argentine head.
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There were also Al-U-minimum double squish Slanty heads by Mopar, a parallel study to the 1st gen. 2.2l bathtub heads, even a turbo manny setup.
There was a foreign head I posted in Uncle Tony's Hemi-six cyl. thread, the images compressed on Me into a horizontal line, they were photobucket postings & I'm sure they expired. I may have a "cheat" to try to recover them, We shall see. I believe the poster/owner was member polara1974 on .org. Slantsixdan recently inquired if anyone had heard from them lately.
 
Killer6 said:
There were also Al-U-minimum double squish Slanty heads by Mopar, a parallel study to the 1st gen. 2.2l bathtub heads, even a turbo manny setup.
There was a foreign head I posted in Uncle Tony's Hemi-six cyl. thread, the images compressed on Me into a horizontal line, they were photobucket postings & I'm sure they expired. I may have a "cheat" to try to recover them, We shall see. I believe the poster/owner was member polara1974 on .org. Slantsixdan recently inquired if anyone had heard from them lately.
Click to expand...
By all means, please try!
 
Killer6 said:
There were also Al-U-minimum double squish Slanty heads by Mopar, a parallel study to the 1st gen. 2.2l bathtub heads, even a turbo manny setup.
There was a foreign head I posted in Uncle Tony's Hemi-six cyl. thread, the images compressed on Me into a horizontal line, they were photobucket postings & I'm sure they expired. I may have a "cheat" to try to recover them, We shall see. I believe the poster/owner was member polara1974 on .org. Slantsixdan recently inquired if anyone had heard from them lately.
Click to expand...
Correction, SSD was asking about member Dusteridiot over there, Rick Covalt asked about member Polara1974. Also, the images I have of the other foreign head are on the newer PC drive, that HP tower has crashed,...the hard drive won't hook up to the other one to see if it's the drive or motherboard, so I have to regroup on that project...
 
Check out how close a Jag head is to our Jane's.....any Sadist wanna try and get one going, OHC style?
Used-Cylinder-Head-For-Chrysler-And-Dodge-With.jpg

head_new_bottom-070607.jpg
 
SpriceyStuff said:
Hey guys. I got a (maybe not so)crazy idea. I have a late model slant six in my car (77), and I have an earlier model engine laying around.
Click to expand...

I would be more then happy to traded a rebuildable drool plug head for a rebuildable peanut plug head. I am about an hour away from you.
 
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