I currently drive daily my 74' duster with the origional /6. The motor has 85,000 origional miles, but is soooooo slow. I wanted to rebuild it, but am not sure how crazy I need to go with it to get good power. I need to be able to run power steering, a/c, and hold a good idle. I drive it daily so it needs no overheating problems in summer. Its backed by a 904, and i would prefer the engine run on no more than 91 octane. Fitting that criteria, i wanted to know how much hp/tq i could pull out of the motor alone. I have seen over 200, but would like your input. as far as boring out the motor, new pistons, head work, i do not mind changing or modifying. your input on how much power i can get is appreciated. thanks.

Before you do any reboring or rebuilding, I would super six your Duster. I would also replace the original exhaust pipe and muffler with a larger diameter pipe and free flowing muffler. I would recommend these two upgrades first.
Many folks like the MSD ignition setup, but I haven't done it personally. There is much you can do to improve your slant six's performance before you need to rebuild it, or do anything more radical.

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

Also, if your Duster has any emmissions equipment, removing/disabling it can help performance.
Disclaimer: This modification is for off-road purposes only!

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

You've got a heavy '74 car loaded up with heavy and power-sucking options and an original-miles engine probably still laboring under the strangulation emission controls installed at the factory in 1974. And it's all in front of a super-tall 2.76 rear axle ratio and relatively tall tires. Put the brakes on your rebuild/hop-up idea; you're not at that point yet. It's also not yet time to put a 2bbl (Super Six) on your engine.

Start from the start. First question: Where do you live and what kind of emission test, if any, does your car have to pass?

If you mean slow off the line, then you may find that simply upgrading to different rear end gears will smoke the tires make the car much more enjoyable. Cost: under $500 and way cheaper if you do all your own work.

A super six and bigger exhaust will add around 10 horsepower if I recall correctly. Cost: $500 is a rough estimate depending on where you get parts and who installs your exhaust.

If the motor only has 86k miles, it shouldn't need rebuilt yet. If you are unsure, do a compression test. I don't believe you will get your money's worth out of overboaring just for the heck of it.

This list goes on and on. Check out the rest of this forum, and see what the guys with quick cars have done to get there.

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1980 Aspen 225 super six

As for the comment about my duster being a heavy 74 car, it is actually fairly light. The car tips the scales at 3200 lbs right now. I also plan on making fiberglass fenders, hood, and deck lid to lower weight to hopefully 3000 lbs even.

As for the emmisions, i have already taken most off of the car, and it does have good compression.

Next, the car isntisntribly slow off the line, but nothing to brag about.It is a dog at anything over 45 mph, especially highway speed. I do not want steeper gears because i drive aalot on the highway, and around town. I see 23mpg on the highway with a/c, and 19 city also with the factory a/c on.

I am just on a quest for a daily driver trip taker that could hold its own at a stop light or highway brawl.

Plan on doing lotsa work, or install 4 barrel, mild cam LA small-block V8 for the simple/common approach

D/W

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If it ain't broke, fix it!

Here at a junk yard(easy pull)in eastern pa I scored a super six intake and exhaust manifold for 30$,and walking the yard I found or peaced together an exhaust system for another 35$ the exhaust pieces weren't even rusted,the carter bbd I found was off a 318 for 20$,rebuild kit 20$,its all on my truck now and finely got the bugs worked out and it runs good,just my 2cent,,,speedfreak.

my econo choice........forget cams and 4bbls......go with a supersix 75 a set of clifford headers y'ed into 1 2.5 in pipe 400 and a used 3.23 rearend 100 so for 575 you will have a really reliable semirocket. save 400 on the exaust forgo the headers and just run the supersix exaust you wont loose too much and still have lots more power than you had before

By the way, when your car was referred to as "heavy", that's a relative term. At 3200 lbs, it's 400 pounds heavier than some of the early- to mid-60's Valiants.
That weight usually makes itself known across the board, so I think there's something else holding you back.
Keep plugging away, upgrade here and there, and you'll have a nice, responsive, practical Dart!

I'm sorry, but although "super six" is nice and a highly recommended modification over a stock 1bbl (I know, I ran my Duster in that configuration for years, with headers as you mentioned), it won't hold it's own at any stoplight or highway brawls, which moparman/74/ stated as one of his requirements. Gonna have to do some headwork/cam change to make it even respectable, or just go to a V8.

D/W

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If it ain't broke, fix it!

If you are looking to reduce weight then look into the bumpers and all the cast iron hanging on the side of the engine. Glass fenders hood and deck lid will only save you 50-75 pounds. My aluminum super six intake and headers(clifford shorties and Y-pipe) weigh over 40 pounds less than the cast iron 1-barrel intake and exhust manifolds. the reinforcement behind the bumpers couldsave you another 150 pounds. to see any real power you need to have the head shaved and ported. I had 0.100" taken off of mine and I ported it. I now have to run premium(92-93 octane in this area) I am running the stock bottom end and cam(the crappy pre 71 cam) with 102,000 miles. when I was using the 8 1/4 with 3.21's It ran 16.8 in the 1/4 mile. We (me and the Green Machine) have won our share of highway wars.

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...I guess it's just a subjective opinion, and what kind of econobox one intends to "choose" in these "highway wars". With the Duster running mid fifteens, I don't really consider that worthy of a stoplight brawl, unless it's against some pansy-ass "tuner" wannabe with a trashcan tip and the thump "music".....

D/W

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If it ain't broke, fix it!

Thank you all very much for your input on what to do with my engine combo in the duster. I got a lot of good ideas from everyones in put, and hopefully will be better prepared to tackle my engine next. I really like this site, it is very useful, a great tool, as well as source of information and opinion.
thanks.

Allen- moparman/74/

I didnt say stoplight wars. Most of the tuner wannabes around here seem to be afraid of going into triple digit speeds. If you are willing to hit 110-115mph they tend to back off. I am really looking farward to the spring when I get the new engine in. There are very few real import tuners around here though. there are so many SUV's and minivans it can be difficult to find a good stoplight race in this area.

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