Hi guys, I need a little help here. I am pretty new to the slant six scene. I am 15 and getting a first car. It is a '73 Duster w/ a 225 /6. The engine is low on power and i want to fix that. I want a healthy street mill that will perform well being driven daily and will have decent power. The thing is, I blew all my money on the car so this needs to be very low buck. What upgrades should i make to the engine/whole car to make it perform better without spending a lot of money? This should be a cheap, fun project that will pay off later.
Thanks

Welcome on board! Sounds like a good starting point. My number-one recommendation to you would be to consider any modifications you might think to make very carefully and ask lots of questions before you do them. "Upgrade creep" is a very real danger once you start in, and it is often accompanied by sharp shooting pains in the wallet area. Not saying you mustn't ever modify it at all—there are some modifications that produce very real benefits with very few drawbacks—just learn and think and ask before you do.

Recommendation number two: Even ask before you do simple stuff like tune ups and oil changes and regular maintenance. There are certain techniques and parts you can pick to make your car work a little better.

Recommendation number three: Buy and read books. A factory(!) service manual, a Stockel book and the Petersen book discussed in this thread here. Worth more than their weight in gold.

Where in Colorado are you located? Emission testing is in place pretty much clear across the Front Range, but for pre-'81 cars it's the old FTP75 "idle and 2500 RPM" test, not the dyno test, as far as I know. You have a lot of wiggle room to change and improve things without running afoul of the emission test. There's a fair amount you can do in the way of tweaks and improvements without spending any (or much) money compared to what you'd spend anyhow for tune ups and other maintenance work.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I live near denver but the law for emissions is that it has to pass the emission law that was set that year (a '71 would have to pass the emissions from 1971) so its pretty easy to get away with stuff. No cat. converters, no emmisions control stuff so thats pretty cool. I have been reading a lot about the slant six, and a friend has the factory repair manual for all cars from '60 to '75 so that is covered too. I would just like to know about some cheap, sensible upgrades that will improve my get-up-and-go performance. Thanks

That's not quite how Denver's emission test regime is set up, with year-by-year standards (actually the groupings are '55-'67, '68-'71, '72-'75, '76-'80, '81) but you're right, there's a lot of leeway for a '73.

The pickings aren't as good as they used to be, but Colorado Auto and Parts (303-761-0112) has a variably large Chrysler/Dodge/Plymouth section and a separate all-makes truck-and-van section; bring your tools. Another good self-serve wrecking yard is Pull 'n' Save, out off Peoria not too far from the airport. Find a '76-'80 car, truck or van with a slant-6 and 2bbl carb and grab everything (intake manifold, carb, throttle cable, trans kickdown linkage INCLUDING the lever on the trans, linkage brackets and springs, air cleaner). This will make a nice driveability and power improvement compared to your present 1bbl setup. You may even want to take a hacksaw and take the top 8 inches or so of the exhaust headpipe on such a 2bbl-equipped vehicle. Its 2-1/4" diameter will someday form the basis of an upgraded exhaust system.

Your present rear axle ratio is 2.76 if you've got an automatic transmission. Probably a 7-1/4" rear axle (look at the number of bolts holding on the rear axle cover plate. Nine = 7-1/4", ten = 8-1/4"). Not very conducive to quick acceleration. You'd be much happier with a 3.23. These are tougher to find in wrecking yards, but Bob Schwartz (303-779-1865, tell him Dan Stern sent you) may have one from a stick shift car.

OSAC valve: Bypass immediately!

Distributor recurve can help out a lot, but there's no prescription for a magic formula that will be correct for your car at your altitude. It can be tough to find someone with a distributor machine AND the knowledge to use it, but Deluxe Speedometer & Radio over on Speer (303-629-6958) still had Sun machines last time I checked. You'll need to do a lot of homework before you bring your distributor to them.

When you put in new spark plugs, make 'em NGK ZFR5N or Autolite 985s, gapped to 0.040" (remember, remove the ring gasket from each plug before installing it!).

That should be enough to get you started...

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Too many people who were born on third base actually believe they've hit a triple.

Thanks for the advice dan. I was wondering how you know allt this stuff about colorado though! i thought you were in canada! Anyway thanks a lot, and this seems like a good way to start things off. Thanks, david

I lived in Denver-Metro for over 20 years. Left for the last time in 2001.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

oh thats cool dan. well thanks for all the advice. I was also wondering about some suspension mods. I want to put v8 sized torsion bars and leaf springs in my car and probably front and rear swaybars too. I was wondering what kind of handling i would be looking at?

"Much improved".

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That setup sounded pretty sweet, so i would be willing to give up some horsepower for sweet handling. Do you think that is a pretty good tradeoff? Because i would rather race a road course than a strip.

hey dan, i was wondering about oversized valves in the /6 head. I recently read an article about doing so in the slant six. I also read one about doing so to the 318. The price to make the seats larger for the 318 was $220. The slant six article did not say. The valves for the slant six were very expensive(around $150 per set.) they were 1.74 int and 1.54 exh i believe. These valves can be purchased for around $120 for all of the valves. I was wondering if you could fit standard 318 sized valves into the slant six head. those are 1.78 int and 1.60 exh. I would only have to pay for the valve seat enlargement and the valves because i have a friend who can help me with the porting. Thanks again, and i was just wondering if this would provide significant gains over anything else.

There's a lot of bolt-on/fix/modify stuff to do before you go making the valves bigger. It's counterproductive to start with bigger valves.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

It would be cheaper to use a 360 head on the 318. The compression ratio will drop about 1 point. With a .030 overbore, you can use 2.02 and 1.6 valves with good results.

There are numerous valves that can be used, the best may be from SI Valves. They are 1.70 intake and 1.44 exhaust and have the same stem size and length as the OE valves. They want around $12 a piece. Some people have used Ford 300 six valves, some Ford 289 valves and some chevy 1.72/1.50 valves. These require an overbore of at least .030, the guides need to be changed to 11/32s and the stem length needs to be shorten.

Is this a good first modification, maybe. There have been reports that coupled with the SuperSix manifold and headrs, there was a noticable improvement in performance. How much of the improvement can be attributed to the valves is anybodies guess.

ok dan. well i was wondering about maybe just porting or smoothing out the ports. Would that help any?because my friends dad can help me with all of that for free. i was just wondering about the valves because i read an article about a 318 where the only mods were a 4 bbl, headers, cam, and ported heads w/ bigger valves and they made 400 hp. just wondering. Hey if the 225 has 145 hp stock, i was wodering on approximate power from a 2 bbl, new exhaust, and maybe a rear end swap(maybe to a 3.23 i read that you can swap 3.55 into a 7 1/4 rear end). This seems like a good setup, and since your the expert and i should listen to you, i was hoping you could tell me. thanks a lot dan.

by the way i was just reading some more posts and i read that slantsixdan is actually doug dutra! i cant believe i was talking to you this whole time and i was calling you dan! I was wondering when i would actually get the chance to talk to you! Also, i read a lot of your articles Doug, and they are great! You have done some great work! I especially love the one where you teamed up with Mopar Muscle Mag and built that amazing /6 to run 14's! That was awesome. That is actually where i got the idea to enlarge the valves. Tanks for the great advice and reads doug. I cant believe i was that stupid! LOL

Errr... Slantsixdan is Dan, Doctor Dodge (or Doc) is Doug D. (or DD)
Either way, your in good hands, Dan has been around Slants for a long time and he knows which way the bolts turn!
DD