170 or 225 for super 6 build?

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73goldduster

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i've finally got some cash together to start building a super six.
i'm thinking just a 2bbl, headers, and maybe some head work (gasket matching, milling).

i've got a 225 in the duster now, and i found a motor on ebay pretty cheap.
it's a 170 from a 67 dart gt. comes with 904 trans. he says the motor is a runner.

which would be better for my build? i heard that the 170's have a shorter stroke and can rev higher, so more top end power? if i'm just doing a mild hop up, would there be much difference?
 
You are giving up 55 cubes with the 170 or 9 cubes /cylinder or 25%.
You could throw a ton of money at the 170 and still not run with the 225.
Save it for a resto.
 
i would use the 225. the 170's have clearance issues with clifford headers because the block is about 1 inch shorter. im not sure about the hooker headers.
 
NO ONE makes 170 headers. Clifford used to make long tube for early A's. But they havent in years.
As most have said use the 225. Unless you are going to a full boogie race motor the 170 wont do much.
Frank
 
3rd vote for the 225. Yea a 170 will rev higher but you sill still get less HP at 6500rpm than with a 225 at 5000rpm.
 
to answer your other questions Super six is great , Head work is where its at. headers with 2 1/4 exhaust is best.
Frank
 
225 for sure, I will have one one day, And frank will be my engine builder
 
The obvious knock against the 170 you are looking at is that it is a '67 motor and will have the small register in the crankshaft. That opens up it's own can of worms in the transmission/converter department.

A friend of mine did a full race 170 for a customer. The car is fast with the 170, but for the same money a 225 would probably be a full second quicker.

If you're limiting yourself with a 2bbl, why further handcuff yourself with a 170?
 
If you're limiting yourself with a 2bbl, why further handcuff yourself with a 170?

i'm going the 2bbl route cause i'm unsure of the streetablility of a 4bbl setup. also i dont wand to mess too much with the reliability factor. i really dont want to be exploding transmissions and rearends. or punching holes in engine blocks.

i figure, go with the milder setup now, and once i get bored with it (or get more money to fix more broken pieces!) i'll just do an intake and cam swap.

that said, any opinions on the streetability of 4bbl setups?
 
Road-ability is pretty good. Best economy I got out of the Hooptie was with a Holley 390 and 600 4160. (About 23 with either.)
Steet-ability is great if your looking for zap. The 390 will deliver liveable economy. The 600 will not get good mileage around town.
The 390 is a bit easier to tune in than the 600.

Better yet is the Carter AFB. It pretty much just bolts on and goes. Same with the Edelbrock. Pretty much the same thing.
Economy hasn't been as good as the Holleys. But I did a bunch of stuff to the engine to take those five seconds off at the strip. Apples and Oranges you know.

That said, with the Holley 4 bbls there is a bunch of jetting and general bandaid-ing needed to get the mixture right in all modes. Jets, power-valves, secondary springs, secondary idle setting is a skosche off factory, pump cams, and shooters. It takes quite a bit of work to get the A/F meter to read on the gauge, much less in the middle.

A BBD that is the correct one for the slant six is, of course, much easier to deal with. It's already set up the way it needs to be.
There is a bunch of messing around with BBD's that were used on v8's, and I wouldn't even bother with the Jeep units. Too many differences.

I don't daily drive my Valiant with the Carter 600 on it, but I could in a pinch. I'll probably convert it back to a 500 shortly. It's harder to keep the mixture right with the larger cfm boosters in there.

With any 4bbl, to get things working right, the distributor curve needs to be re-worked. There is no real advantage to a 4bbl until you get into the 9:1 range with compression and do something about the 170 head bolted to every slant since day one. :D

CJ
 
To look at the 170 vs 225 in another way.......grab a Hemi piston in one hand and this picture in the other hand.













250cc6CylPistonandRod.jpg
 
73goldduster said:
If you're limiting yourself with a 2bbl, why further handcuff yourself with a 170?

i'm going the 2bbl route cause i'm unsure of the streetablility of a 4bbl setup. also i dont wand to mess too much with the reliability factor. i really dont want to be exploding transmissions and rearends. or punching holes in engine blocks.

i figure, go with the milder setup now, and once i get bored with it (or get more money to fix more broken pieces!) i'll just do an intake and cam swap.

that said, any opinions on the streetability of 4bbl setups?
Click to expand...

Duuuude, you're building a Slant, not a Hemi. Even a good 225 will not grenade rear ends or transmissions unless you're a complete tool.

390 Holley and an Offy intake is one of the most streetable combinations you'll ever find. I went about as far as I could with a BBD on my old Duster. Simply bolting on a 390/Offy picked the car up 6 tenths and 7 MPH. That is some serious steam.
 
I've been running a 4bbl on the street for years. It really is over kill on a stock slant though. My compression is at 9.8:1 the head is ported, headers, mild cam, and I rarely get into the secondaries. I get 16mpg around town and 21 highway if I keep it under 70mph, 19 mpg at 75-80 mph.
If you aren't going with a big cam then stick with a Carter BBD, I ran a V8 BBD on mine for a while, much better than the /6 BBD. The 465 Holley I have now only helps over 4000rpm and I rarely ever rev that high unless I'm on the racetrack.
 
I have been running a holley 600 for a few years and it's very reliable, starts every time and pulls 23+ mpg. It did not take much to get it to run right but i like to fiddle with stuff, If you don't it might take some time. A cold climate will hamper things with the open intake... It needs heat to run right! The 225 will give more power, If you do the head, I.e. port and polish for flow then you can make some power!

TF
 
Can a 170 be made to have any power at all, I have a 64 170 sitting in my garage that I want to use, cause I already have it, in a home built fiberglass car. I want to use side draft carbs from a 59 Volvo that I also already have. So milling the head, cam, headers and side drafts can I get 200 hp out of a 170, what about building a stroker out of 170.....sorry for the thread highjack..
 
Yes you can make it move. A 170 is a fun motor. Get with Charrlie S about really getting the most out of a 170. This is what he races with all the time. Ive seen alot of 13 sec passes with his car that weighs 3000lbs personally.
Frank
 
One of our Killer Bees, Wayne is running in the high 12's on the motor with a 170. It's a very light car.
Doc has done some Stroker 170's using the 198 crank and a .100 over bore. Look in the Articles section on dot org.
I have one of those projects in my shop. Haven't gotten anywhere with it. The fixin's make a 210 CI.
I was going to use it for my next car, but I've been eyeballing the BH block that came out of my Valiant instead. Building power in a slant six is the hard way to do things to begin with. Doing it with a low deck block is the super hard way.
That said, building big power in a 170 is possible. Passing a certain point on the hose is courting disaster.

It's enough of a "Holy ****" factor, when the crowd hears that the slants are going to run and get up for a beer run. Someone like Dave M with his Alcohol Injected 225 Valiant wagon leave the line with the front wheels off the ground, pump out something in the 11's, and the crowd stays to watch. :D
When a 170 does it, the slant six crowd gets saucers eyes, but the rest of the world doesn't know the difference, just that the cars are cooler than they expected.

A fun one I had was a run in Woodburn last year. I got put up against a kid with a stroked small block in an El Camino during time trials. He was bragging up his car in the staging lanes.
He didn't know what he was doing, so I clobbered him. At both ends which was a surprise to me. When we got back around, he started asking questions. I popped my hood and he about died. Fun stuff!
I helped him with his setup, and staged with him again. He ran almost a second quicker than I did the next run. His lights were rotten though. :D

CJ
 
I have the two frame halves from a junked Valiant, I am going to join them and put a Fiberglass body on the frame.....170 side draft carbs and six pipes pokin out the side. I want the weight to be around 1800 lbs with me in the car, like a low slung British racing car....but mostly if not all Mopar....I already have a 3:23 gear 7 1/4 rear end, aluminum 4 speed bell housing, the carbs and various other peices.......now all I need is the cash.....
 
Let me know if you find any.

I've been short since I started racing.... :lol:

CJ
 
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