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PostPosted: Wed Nov 15, 2017 1:56 am 
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4 BBL ''Hyper-Pak''
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Posts: 31
Location: Waco, TX
Car Model*: '69 D100
Hey everybody, nice to be back...

I hope I'm not dragging the horse out of its grave and beating it with a stick, but I'd like to know how to get to 180-200HP while maintaining reliability and mileage, within reason. Forced induction is an option but is expensive and taking me a long time to wrap my head around, so can it be done N/A? I plan to make these upgrades already:

- 0.10" off the head
- Electronic ignition (done)
- Super six manifold and Carter BBD
- Headers or Dutras, w/ water-heated or heater-piped intake

As far as I can tell that would only net about 50HP or so, maximum. From what I gathered through searches a hotter cam and ported head might take me the rest of the way... is that right? It doesn't quite seem to add up, given we're working with 100HP from the factory. My biggest concern, and which I couldn't really discern from searching previous posts, is how all this head and cam work potentially affects reliability and driveability. Can the /6's reputation as a tank largely be attributed to the low compression and output from the factory?

I would like to get to 180 because I have considered selling my truck for a newer one with P/S and more power, but if I can get to 180HP, then even after subtracting around 20HP for compressors and P/S pumps, it might be highway streetable with 3.23 gears (currently running 3.55 on small tires).

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PostPosted: Wed Nov 15, 2017 3:54 pm 
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Quote:
how all this head and cam work potentially affects reliability and driveability.


In the HP range you are talking about the cam, springs, Head ....etc should not affect reliability at all. A set of 340 springs or engine builder springs are good for up to @500 lift and big valves and porting have no effect on reliability that I can think of. If you pick up a real 50 HP you will be amazed at how well your truck runs. I left the 3.55's in my D100 and love them. The lower gearing gives you the feeling of more HP without sacrificing any driveability.

Rick

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PostPosted: Sun Nov 19, 2017 1:44 pm 
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EFI Slant 6
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Location: Springtucky OR
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Zack wrote:
...Can the /6's reputation as a tank largely be attributed to the low compression and output from the factory?...


It isn't just the low compression and modest power output that makes the slant so solid.
A lot has to do with an engine block that was designed to be made in aluminum but ultimately was produced in iron.
Along with that a crankshaft with bearing journals the size of a 440 big block makes for a pretty robust foundation.

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PostPosted: Sun Nov 19, 2017 3:18 pm 
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Zack wrote:
I plan to make these upgrades already:

- 0.10" off the head


You best not just randomly take some random number of thousandths off the head. Put in the time and effort to measure your combustion chamber volume, then you figure out how much to shave off the head and/or block to get the CC volume and compression where you want them to be.

Quote:
Electronic ignition


An OK stop on the way to the HEI upgrade

Quote:
Super six manifold and Carter BBD


One of several good carburetion options. You might want more (such as a Motorcraft 21-series carb).

Quote:
Headers or Dutras, w/ water-heated or heater-piped intake


Dutra Duals.

Quote:
a hotter cam


Dutra RV15-RDP

Quote:
and ported head


You're definitely going to want to spend money, time, and effort on the head.

Quote:
we're working with 100HP from the factory.


That depends on what numbers you're using when you talk about horsepower.

Really better to think in terms of what you want the car to do, rather than horsepower numbers that don't actually help except when you're bench racing.

Quote:
how all this head and cam work potentially affects reliability and driveability.


Do your homework and proceed thoughtfully and you'll wind up with a car that runs well for a long time. Cut corners or try to "cookbook" it, or do it backwards (pick parts because they look cool), and you'll likely wind up with aggravation and despair.

Quote:
Can the /6's reputation as a tank largely be attributed to the low compression and output from the factory?


They hold up very well when hopped-up thoughtfully.

Quote:
I would like to get to 180 because I have considered selling my truck for a newer one with P/S and more power, but if I can get to 180HP, then even after subtracting around 20HP for compressors and P/S pumps, it might be highway streetable


Throwing around horsepower numbers doesn't achieve anything.

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PostPosted: Mon Nov 20, 2017 6:42 am 
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Your best bet is to find a reputable shop that does head porting, hopefully with the help of people on this site. If you spend $1000 on the head and do the other mods, you should be in the 180-200 HP range. Perhaps Doctor Dodge (PM him) would be interested and willing to do a good head for you??

All the best,

Lou

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PostPosted: Sun Dec 10, 2017 10:18 pm 
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4 BBL ''Hyper-Pak''
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Location: Waco, TX
Car Model*: '69 D100
Only just saw these responses, thanks all.

Rick Covalt wrote:
In the HP range you are talking about the cam, springs, Head ....etc should not affect reliability at all. A set of 340 springs or engine builder springs are good for up to @500 lift and big valves and porting have no effect on reliability that I can think of.
Rick


That's good to hear, I guess my assumption was just that there must be some sort of trade-off between performance and reliability, or mileage as it were. Especially in the case of using parts like 340 springs and bigger valves, why would Chrysler engineers opt against these things? Is mileage adversely affected?

ProCycle wrote:
It isn't just the low compression and modest power output that makes the slant so solid.


I know there's much more to it, but I was worried that these factors were significant, or the even the most significant. From all the responses it seems that is not the case.

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PostPosted: Sun Dec 10, 2017 10:41 pm 
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4 BBL ''Hyper-Pak''
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Joined: Mon Jun 19, 2017 7:25 pm
Posts: 31
Location: Waco, TX
Car Model*: '69 D100
SlantSixDan wrote:
You best not just randomly take some random number of thousandths off the head. Put in the time and effort to measure your combustion chamber volume, then you figure out how much to shave off the head and/or block to get the CC volume and compression where you want them to be.

Thanks for this advice. How should I determine the displacement and compression that's ideal for my purposes? As a general idea, the more you take off the head, the higher the compression, right? I know I would like more compression and more power without significantly affecting the structural integrity of the casting, but not much more than that. Should I start with a very low number to true the deck and leave room for future work?

Quote:

Hear me out... I know Dutra Duals are superior to headers in most ways such as durability, fit, maintaining intake heat, etc, but I've got some fun ideas I wanted to try with the headers, and what would be the point if not for fun. And they do indeed look cool, sue me. I've never had headers before so I just have to scratch that itch. Rest assured I won't be buying internal components based on their looks.

Quote:
Dutra RV15-RDP

That's an interesting one, did not know Doug made cams. I will check it out.

Quote:
Throwing around horsepower numbers doesn't achieve anything.

That's right, but I know the Jeep LJ I used to drive made 180 net HP and weighed and handled about the same, so I'm trying (very roughly) to bench race my way up to that mark before I decide what to do.

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'69 D100 3-spd 225


Last edited by Zack on Sun Dec 10, 2017 10:58 pm, edited 1 time in total.

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PostPosted: Sun Dec 10, 2017 10:47 pm 
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4 BBL ''Hyper-Pak''
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Joined: Mon Jun 19, 2017 7:25 pm
Posts: 31
Location: Waco, TX
Car Model*: '69 D100
Dart270 wrote:
Your best bet is to find a reputable shop that does head porting, hopefully with the help of people on this site. If you spend $1000 on the head and do the other mods, you should be in the 180-200 HP range. Perhaps Doctor Dodge (PM him) would be interested and willing to do a good head for you??


SlantSixDan wrote:
You're definitely going to want to spend money, time, and effort on the head.


There is a shop around town called Ledford Performance, any chance someone here has heard of it? I was going to have them do some work on another car first. Unfortunately I can't spend $1000 right now, but I wouldn't want shoddy work either, so maybe I'll just save up. I'll PM Doctor Dodge sometime and see.

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