cleaning up the slant six head

[1930]

Does anyone here have any info on what I could do to my to optimize flow, Id like to see an article with pictures at the very least, a step by step tutorial would be even nicer.

I would just be hacking into the thing without the mentioned help above and chances are I may do more damage than good.

The engine is original to a 1986 W-100 truck, it was of course not built specifically for the truck and I am attempting to optimize the engines capability.

I want people to say I cant believe theres a slant six in that thing, I want to re-engineer a few things with a personal touch so yes I hope something in the way of pictures is also avail.

Thanks for any help

 

[dartnabout]

I wouldn't mind seeing that myself

 

[memike]

A step by step with pictures and the Do Not Do's would be very helpful and I am sure
we have some great tec's here to show us the way 1930, from head gasket selection
to cleaning up the flow some X2 on wanting some tec help on this :coffee2:

 

[BillGrissom]

Check on www.slantsix.org. I recall someone band-sawed a slant head in two to see how much meat there was to allow for intake bowl shaping.

 

[1930]

Check on www.slantsix.org. I recall someone band-sawed a slant head in two to see how much meat there was to allow for intake bowl shaping.

Yes, I am kinda active over there, alot of GREAT people. Knowledgeable, I have seen the head but again without a flow bench I might be pissin in the wind from what I am gatherin.

 

[Darter6]

One good thing is a slant head is cheap to free so you can experiment alot.
Go to the Mopar Muscle Magazine archives,they have a good article on the slant (2004?) Said that they removed 5 lbs of cast iron working the head.

 

[krazykuda]

My head guy used to work in the Trenton Engine plant where the slant 6 was made. He's good at porting and valve jobs (he even does valve jobs on private air planes). He's retired now and does side jobs out of his garage. Where are you located?


I was reading an article on porting the slant six head a while back that said that opening up the bowls will help alot. Of course I can't remember where I saw that now to reread it...

 

[1930]

One good thing is a slant head is cheap to free so you can experiment alot.
Go to the Mopar Muscle Magazine archives,they have a good article on the slant (2004?) Said that they removed 5 lbs of cast iron working the head.

Ill look fort that, if you can get any more specific with it though I am sure it will help me find it. Thanks

 

[1930]

My head guy used to work in the Trenton Engine plant where the slant 6 was made. He's good at porting and valve jobs (he even does valve jobs on private air planes). He's retired now and does side jobs out of his garage. Where are you located?


I was reading an article on porting the slant six head a while back that said that opening up the bowls will help alot. Of course I can't remember where I saw that now to reread it...

Florida, my e-mail is jhason2@yahoo.com if you would like to give it to your guy or give me his if avail. Thanks

 

[TXDart]

Justin did my /6 head,here is the link:
http://www.forabodiesonly.com/mopar/showthread.php?t=238600
Got some great flow out of it.
Pm me if you want his email.

 

[cjh]

Bottom head is stock untouched.......on the top one, the exhaust ports are as big as the intakes on the stock head......also, the top head has had about 0.140" taken off it.

 

[1930]

Bottom head is stock untouched.......on the top one, the exhaust ports are as big as the intakes on the stock head......also, the top head has had about 0.140" taken off it.

How does the head flow in comparison to a stock head, what was the cost of having the work done and do you feel the money spent was justified?

Did you do the work yourself? How was it done, must have been some sort of guidleline that was followed.

Looks good BTW

 

[cjh]

How does the head flow in comparison to a stock head, what was the cost of having the work done and do you feel the money spent was justified?

Did you do the work yourself? How was it done, must have been some sort of guidleline that was followed.

Looks good BTW

I did the head many years ago, never seen a flow bench, did it by feel and look......port matched.
I had it on a slant that was 0.060" over, mild cam, headers, 2 & 1/2" exhaust, Mercury Turbo muffler, 2bbl intake, 350 Holley, regraphed (points) dizzy, Bosch GT40 coil, 14" open aircleaner, heavy duty clutch, BW 4sp close ratio box, 3.45 gears.....and would leave a 1973 XA Ford GT 351C Hardtop behind, and would run out at 120 mph.
Tried it on a drag strip, street tyres let down to 18 psi, and all I could get was a 16 sec 1/4 @ 89 mph.....was spinning into 3rd gear.....but on street asphalt, whole nother story.

 

[1930]

I did the head many years ago, never seen a flow bench, did it by feel and look......port matched.
I had it on a slant that was 0.060" over, mild cam, headers, 2 & 1/2" exhaust, Mercury Turbo muffler, 2bbl intake, 350 Holley, regraphed (points) dizzy, Bosch GT40 coil, 14" open aircleaner, heavy duty clutch, BW 4sp close ratio box, 3.45 gears.....and would leave a 1973 XA Ford GT 351C Hardtop behind, and would run out at 120 mph.
Tried it on a drag strip, street tyres let down to 18 psi, and all I could get was a 16 sec 1/4 @ 89 mph.....was spinning into 3rd gear.....but on street asphalt, whole nother story.

Thanks for the info, too be honest with all the feedback I have been reading unless I am building an all out high RPM race engine ( which I am not ) spending an ungodly amount of money paying someone to do the head would be a waste of time/money. My engine will prob never see over 4500 RPM on its worst day.

I think I will go the route you chose to go, if you ever have any spare time and any tips you would not mind sharing my e-mail is jhason2@yahoo.com

Either way thanks for the pics, it looks like you did a great job.

 

[cjh]

I forgot to mention, I did a compression test on that engine...a dry test....it had 240 psi.....on a 250 psi max gauge......thought that wasn't right, so I got a lend of a screw in 300 psi max test gauge, and yep, it had 240 psi.....glad I was running good 98 RON juice in it.
That engine would rev to 5,500 rpm.....and when driven hard, the tank of fuel just didn't last.

Some other heads I have done.....love doin alloy heads, takes no time at all to do.

 

[1930]

I have been told that for street use polishing chambers like that would not only be a waste of time ( cause 100 miles down the road they would be all carbonized and way ) but it may actually cause more problems with quenching/flow.

Either way they sure look pretty.

 

[1930]

Any suggestions on what I can soak my 1984 cylinder head in?

I am going to re-condition that one I am thinking and leave my already re-built 86 head as a spare.

I have read soak it in vinegar, Coca-Cola, and personally know Lysol toilet bowl cleaner to work very well on de-rusting parts but have never attempted using it on a cylinder head.

Lots of carbon build-up on the head.

Id prefer to maybe stay away from the Lysol, I know its pretty caustic and I am concerned with large amount of flash rusting once the head were removed from the solution in areas that I may not be able to treat without an additional dipping step.

I know I could just pay to have them cleaned but Id like to do as much work myself as possible to save cash and by the time I drop them off, pay to have them cleaned and go pick them up I may have spent quite a bit more than a few bottles of Coke and the Coke might do just as well of a job.

What do you guys use?

I can be posting pictures as I go along if there is any intererst?

 

[ntsqd]

A cylinder head guy once told me two things to keep in mind when working on ports. Low lift flow is more important than max lift flow because the valve spends more time there. It's an area under the curve kind of thing. The other thing that he told me was that the short-side radius is where the magic happens.

Personally I'd just gasket match the intakes down 3/4"-1" into the port and leave a small step on the exhausts.

 

[1930]

Personally I'd just gasket match the intakes down 3/4"-1" into the port and leave a small step on the exhausts.

Thanks for the other tips, I will add them to what I need to look into.

Can you explain further what you mean here though, give me more details.

It sounds simple enough that I should be able to grasp what you suggest but being a novice at this sort of thing leaves me still a bit confused and looking for details.

 

[ntsqd]

Dykem (or Sharpie :thumrigh around all of the ports, align the gasket and gently scribe a line at each port on the head around the gasket's opening. Open up the intakes to the scribed line. Open up the exhausts to within, I dunno, ~3/32" of the line (smaller). Blend all ports down 3/4"-1" into the head.
The idea in the step on the exhausts is to create an Anti-Reversion (AR) feature. Can probably devote a whole thread just to discussing AR, but the OE's have done fairly well w/o paying it much attention.

Alternately can open up the header or exhaust manifold bigger than the gasket opening and bring the exhausts to the scribed line, but given the RPM range you don't need every extra CFM that you can squeeze out of the ports and keeping the port velocities up is more important than gross flow. though I'm doubting that the difference would be huge, it is less work to put the AR feature in the head and leave the exhaust manifold/header alone..

 

[1930]

Dykem (or Sharpie :thumrigh around all of the ports, align the gasket and gently scribe a line at each port on the head around the gasket's opening. Open up the intakes to the scribed line. Open up the exhausts to within, I dunno, ~3/32" of the line (smaller). Blend all ports down 3/4"-1" into the head.
The idea in the step on the exhausts is to create an Anti-Reversion (AR) feature. Can probably devote a whole thread just to discussing AR, but the OE's have done fairly well w/o paying it much attention.

Alternately can open up the header or exhaust manifold bigger than the gasket opening and bring the exhausts to the scribed line, but given the RPM range you don't need every extra CFM that you can squeeze out of the ports and keeping the port velocities up is more important than gross flow. though I'm doubting that the difference would be huge, it is less work to put the AR feature in the head and leave the exhaust manifold/header alone..

Now that I get, thanks again

 

[cjh]

I have been told that for street use polishing chambers like that would not only be a waste of time ( cause 100 miles down the road they would be all carbonized and way ) but it may actually cause more problems with quenching/flow.

Either way they sure look pretty.

Have a look at a spray gun for painting.....nice and shiny....there is a reason for this.....makes it really easy to clean.....when the gun gets scratched up over time, it gets harder to clean the paint off.

Carbon doesn't stick to a highly polished surface to well.
A bottle of injector cleaner every so often will help keep it clean, as does giving it the berries every so often too.

All the engines I have built over the years have made really good power for the work and parts used.....none have failed.
I managed to see one 10 years after I built it.....it was an old fella driving it (was a young fella I built it for), and all it needed at that time was some plugs, and a tickle of the carby......but I could tell it hadn't been looked after, I took the oil cap off and had a look....could see sludge in there.....only get that from lack of oil changes.
The plugs were so worn, I wouldn't be suprised if they were the ones I had fitted when I built the engine.

 

[1930]

Have a look at a spray gun for painting.....nice and shiny....there is a reason for this.....makes it really easy to clean.....when the gun gets scratched up over time, it gets harder to clean the paint off.

Carbon doesn't stick to a highly polished surface to well.
A bottle of injector cleaner every so often will help keep it clean, as does giving it the berries every so often too.

All the engines I have built over the years have made really good power for the work and parts used.....none have failed.
I managed to see one 10 years after I built it.....it was an old fella driving it (was a young fella I built it for), and all it needed at that time was some plugs, and a tickle of the carby......but I could tell it hadn't been looked after, I took the oil cap off and had a look....could see sludge in there.....only get that from lack of oil changes.
The plugs were so worn, I wouldn't be suprised if they were the ones I had fitted when I built the engine.

Noted, thanks

 

[805moparkid]

the head needs to be worked to increase VE. these heads stock were for a 170ci motor, even fully ported they barely hit 200cfm, nothin... If your going to build one of these the money is in the head...

stock pistons will take alot of rpm and 150 shot of spray, swap the cam out for a regrind and your well on your way...

 

[/6 Matt]

When I read this thread when it was first created, I was hoping it might turn into a head work for dummies type deal.

With zero head work experience, I feel like my best attempt would be nothing more than me blindy grinding away into a water jacket.