Slant Six 170 vs. 225

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And good gas millage
Well...LOL, good as they can get. The 170 can actually knock down pretty decent mileage. The 225 can do "ok". I love the off idle torque the 225 has though. It's pulling pretty much as soon as the throttle is cracked. lol
 
I thought about a turbo. I could still do one on the new motor. But I have looked my one good eyeball out and cannot find a slant 6 turbo install that's clean enough for me. They all have lines, hoses and wires run everywhere and I'm not havin any of it. I like how neat my engine looks now.
 
A basic turbo install doesn't have to have all that intercooler stuff. One install I did took the vehicle from a best of 23 mpg straight to a hair under 30 mpg while almost doubling the power. I was sold.
If you do the work yourself it costs less than headers-intake-carb.

My 225 gets right around 17mpg
 
A basic turbo install doesn't have to have all that intercooler stuff. One install I did took the vehicle from a best of 23 mpg straight to a hair under 30 mpg while almost doubling the power. I was sold.
If you do the work yourself it costs less than headers-intake-carb.

My 225 gets right around 17mpg
Yeah that's about what mine gets. I don't mind the intercooler rigamoroe, I can make that look neat. It's all the other crappola that goes with it. I won't get one without it being both liquid and oil cooled, so there's more lines. Also the blow off valve and whatnot, so there's more stuff. It's just too much crammed in the small space of an early A body engine bay, IMO. If I thought I could do it and keep it neat, I probably would. All that said though, I'm having an absolute blast with it naturally aspirated.
 
The slant is an awesome engine. Wish somebody would make an aluminum head for it.
You don't really need a blowoff with an automatic trans. I hear ya on the water cooling though. Everything under the hood knows there's a hot *** turbo installed, too. Easy bake oven x100
 
The Direct Connection Racing manuals (1978 version) says the SuperSix upgrade is worth 7% more horse power.
 
The Direct Connection Racing manuals (1978 version) says the SuperSix upgrade is worth 7% more horse power.
Do you remember if they included upgrading the exhaust? Even Chrysler didn't use a different exhaust manifold with a larger outlet, but they should have.
 
No, just the intake upgrade.
Gotchya. Then 7% sounds like a fair number. I would think modifying a stock manifold to a 2.5" or 2.25" outlet with a bigger pipe all the way back would net even more.
 
When we were racing my wife's '73 Duster, the 2 1/2" exhaust pipe was the most significant upgrade. The second was a TransGo shift kit in the transmission. The SuperSix and the Autolite 2100 was a distant third. Upgrading to a Offenhauser manifold with the same carb didn't make any difference in elapsed times.
 
When we were racing my wife's '73 Duster, the 2 1/2" exhaust pipe was the most significant upgrade. The second was a TransGo shift kit in the transmission. The SuperSix and the Autolite 2100 was a distant third. Upgrading to a Offenhauser manifold with the same carb didn't make any difference in elapsed times.

Just curious, what are the details on the 2-1/2" exhaust you were running?
 
Don't matter, if he didn't open up the outlet on the manifold flange bigger exhaust won't do squat
 
Don't matter, if he didn't open up the outlet on the manifold flange bigger exhaust won't do squat

Which of course is complete BS. The exhaust was 2 1/2" from the exhaust manifold to the rear bumper. With a noname muffler.
 
yes, it definitely does matter. anything bigger than the actual outlet diameter of the manifold flange doesn't help flow a bit. the 1-3/4 to 1-7/8" hole in the manifold flange is a bottleneck!!!! It doesn't take much with a die grinder and burr, to open the manifold opening. Don't worry, there's lots of meat there// you won't be "too thin" but it DOES make a difference!!!!
Rusty Rat Rod had a thread with pix about this very thing, about a year ago right here........
and the last one I did that treatment to, as cast, the exhaust opening was way off center, compared to a flange gasket bolted up loosely as a guide// so that gives you a chance to "square things up" at the same time. (most of the flange gaskets I have found with that bolt spacing are a 2-1/4" hole, so that's as far as I grind)
 
So the guy has a dilemma: I remember 39 years-ago when I last drove this car that the original 170 was pretty sluggish (around 100 hp?). I would like just a little more pep. (I'm not trying to turn it into a muscle car).

Does anyone know how much HP is created with the two barrel carb with the two barrel intake on a 170?

My other option is...I have a spare rebuilt 1972 225 that only has about 1,500 miles on it that will get me roughly 145 hp. Will I notice a big difference with the extra 45 hp? Obviously a lot more work to do the engine swap.

I don't remember if I had any work done on the 170. I know it never used any oil and the odometer says 165k.

Opinions? Thoughts? You guys are great. Thanks

I always liked a 170 compared to a 225. Use the 2 barrel intake, carb,( better power and mpg) 2" or 2 1/4" exhaust, and for extra credit, mill the head .060 and add a 268 duration cam, valve springs, and a double roller timing chain.
 
yes, it definitely does matter. anything bigger than the actual outlet diameter of the manifold flange doesn't help flow a bit. the 1-3/4 to 1-7/8" hole in the manifold flange is a bottleneck!!!! It doesn't take much with a die grinder and burr, to open the manifold opening. Don't worry, there's lots of meat there// you won't be "too thin" but it DOES make a difference!!!!
Rusty Rat Rod had a thread with pix about this very thing, about a year ago right here........
and the last one I did that treatment to, as cast, the exhaust opening was way off center, compared to a flange gasket bolted up loosely as a guide// so that gives you a chance to "square things up" at the same time. (most of the flange gaskets I have found with that bolt spacing are a 2-1/4" hole, so that's as far as I grind)

Really, do you have a dyno split from before and after the modification? How about a time slip from the track? Do you have anything other then Rusty's butt-o-meter, that shows he thought there was an improvement?

A 2 /12" exhaust pipe bolted directly to the exhaust manifold on my wife's Duster was worth 2 tenths on the 1/8th track that we raced at.
 
Really, do you have a dyno split from before and after the modification? How about a time slip from the track? Do you have anything other then Rusty's butt-o-meter, that shows he thought there was an improvement?

A 2 /12" exhaust pipe bolted directly to the exhaust manifold on my wife's Duster was worth 2 tenths on the 1/8th track that we raced at.
Easy boy, this ain't my argument.
 
Why does everyone seem to require a time slip for things like this?
But you don't understand bottleneck? That outlet is 1-7/8" on most /6s. So how can something larger than that, bolted on behind the said bottleneck, flow any better than that which flows THRU, that size hole????
I definitely wouldn't want anything smaller than the opening for sure.
For 2 tenths difference, that could be coincidence. Or temp. Or reaction. Or any number of things between the 2 runs.
The larger pipe size certainly won't hurt flow... I get that. But I don't get how it can help it either, unless everything is opened to that dimension.
 
Why does everyone seem to require a time slip for things like this?
But you don't understand bottleneck? That outlet is 1-7/8" on most /6s. So how can something larger than that, bolted on behind the said bottleneck, flow any better than that which flows THRU, that size hole????
I definitely wouldn't want anything smaller than the opening for sure.
For 2 tenths difference, that could be coincidence. Or temp. Or reaction. Or any number of things between the 2 runs.
The larger pipe size certainly won't hurt flow... I get that. But I don't get how it can help it either, unless everything is opened to that dimension.
Gases expand once it gets down the pipe, exhaust ports are generally smaller than the tubing headers coming off it. Motorcycles have expansion chambers to make power, my Bul had one iirr 1-18 to 4” then back down to exit at 2”
 
Before swapping engines, I'd make sure that it has had a REAL tuneup. When I got my '68 Dart, poor thing couldn't even get out of its own my. Although it ran, I was afraid to pull out into traffic. I didn't remember them being that slow/sluggish. Looking back, I can't believe how many things were wrong. Previous family had taken it to a local shop (I think it was even the local Chrysler/Plymouth dealer back in the day) to bring it back to life after sitting in a barn/garage for decades. Found them one at a time, each making just a little improvement: stuck heat riser, bad vacuum advance can, stuck distributor weights, valve lash, kickdown linkage. What made the most improvement was taking the "remanufactured" carb apart and setting the float to the correct level. Previous family had owned it since new, but I think part of the reason they let it go was it really wasn't driveable it that state of tune.
 
I would start by adjusting the valve clearance and advancing the timing. And as for the slant turbo being a messy sitch…
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When I got the 70 Duster it had many miles on it, 300 thousand or more. 3speed on column, was so wore out at the bottom I had to shift real easy letting it drop in next gear or pull over and get it out of two gears (carried a long screwdriver for that). Took the stock carb (Carter) replaced with the Holly, ran twice as good. The lady bought it new ($2700). AC and turbo looks like it might be hard to do?!
 
Because the ole butt-o-meter is not very accurate.

At the same time many of us have never run a timed quarter mile, or ever will. I do know what mph my cars would run in a quarter mile. They have all been street cars with exhaust manifolds and decent exhaust, none set up for drag racing. I never figured opening an exhaust manifold outlet would make much difference.
 
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