Hey guys, I’ve been reading this forum since 2020. I’ve fallen in love with the slant six and aspire to see my name on the record list. I’m going to spell out where I am now and where I want to be in this post.
Current build:
1969 Plymouth Valiant 225
Motor
• Bored .040 over
• Milled a total of .050 off the head and block (sadly I don’t know the exact combination—whether it was .020 off the head and .030 off the block or vice versa)
• Head has hardened valve seat inserts, ARP head studs, and 340 springs
• Stock-style replacement cam and pistons
• Stock carb, intake, and exhaust manifold (I ran out of money during the build)
• MSD ignition with a cheap electronic distributor (I know, shame on me)
• Electronic fuel system with a few safety mechanisms (inertia switch, low oil pressure shut-off) — I know Dan is not a fan of electronic fuel pumps, but to each their own
Car / Accessories
• Rebuilt 7¼ rear with 4.10 gears (the only replacements I could find)
• QA1 upper control arms
• 100-amp internally regulated alternator (yes, I did the charging system upgrade)
Future build
• Either mill the head and block further and get custom pushrods, or go with custom forged pistons that have a higher compression height (closer to stock)
• Port the head and maybe add oversized valves (for those who have gone with oversized valves — is it worth it?)
• Mild cam: 220° @ .050, symmetrical, 106 LSA, .460 lift
• ~2500 stall converter
• NOS Mopar electronic distributor
• MSD box with 1–2°/step ignition retard
• 50–75 shot of nitrous
• 3-inch driveline
• Offenhauser intake with some sort of plenum heater
• Clifford headers into 2½-inch exhaust all the way back
• Oil pan baffles
• Holley 390 cfm carb
• Electric fans (Engine Masters convinced me on that one)
• Hopefully an overkill transmission rebuild
• Maybe stainless steel O-ring the block
• Completely overhauled fuel system
• And probably a lot more that I can’t think of right now
My hope is to beat the 3200-lb nitrous record. I don’t have official numbers yet, but from my very inaccurate and absolutely bullsh** phone app I’m running 11.2 at 79 mph in the ⅛. I realize that’s unrealistic, but I can dream.
Anything I’m not thinking about correctly / suggestions? Thank you all for all your help over the years.
— Noah

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1969 Plymouth valiant 225

Glad you are with us!
And good luck with your project too!

I know when I got back to slant racing I thought setting a record was going to be easy.
For me, it has been anything else but easy.
But without a goal and a direction, it easy to get lost!

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Hyper_pak

Hyper_pak, thank you for the warm welcome.
Good luck with your build/car also
I am not disillusioned to the fact that it is going to be a battle but these motors have consumed my life since I got my car and now im kinda the go to guy in my circle when it comes to them. Just wish they were cheaper to build. hope to see your name on the list
-noah

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1969 Plymouth valiant 225

Welcome, Noah! Looks like a cool car and a nice set of goals. You can reasonably be running 11.2 in the 1/8th, but more like 59 MPH, and definitely not 79 MPH. You should have an idea about budget for your dream goals, and for steps along the way. This stuff is definitely not cheap unless you learn to do more of it yourself (like head porting). The D/Nitrous record will take some doing to beat, and let me think about a reasonable combo for that.

You might try to connect with Dave Mueller in Kelso, WA. He knows more about racing Slant 6s than anyone else in the northwest, and has the cars and engines to back it up. He races fairly frequently at Woodburn, OR dragway. There is a small but active Slant 6 racing group out there. If you have not been down a dragstrip, it is hard to even conceive of what it will take to set a record...

Warm wishes,
Lou

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Home of Slant6-powered fun machines since 1988

I second contacting Mr. Mueller.

I hope you are safe up there with the fires going on right now.

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Hyper_pak

Cool build!
…unless they're installed with an inertia switch and oil pressure cutoff, so, no objection here.
https://www.diffgears.com/product/usa-s ... c7-25-355/

https://www.shop.gearcentre.com/chrysler-7-25-/p70043/

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

Dart270 – Thank you. A lot of people don’t like four doors, but I find they are a bit more practical and in some ways better looking
I did build the motor myself the first time (it was my first motor build). Other than the machine work, I did everything myself. So I plan on head porting and doing all I can myself.
When the D/nitrous record was still up, I found either the weight of the vehicle was indicated wrong or the record was placed in the wrong class on the Google Sheet. From what I hope at least, the record is like 10.05 at 70.55 in the 1/8 mile, but the other record that I hope is in the wrong class was a 9.6 or something like that. The Google Sheet link is down so I can’t look right now.
As for Dave Mueller, do you know of a way to contact him?
And I would love to do a drag strip, but sadly as of right now my car would not pass inspection (way too much rubber fuel line and a few more things I don’t have time or money to fix as of right now). I am hoping in the next 4-6 months I can fix the problems and run my current combo down a strip.
Hyper_pak – Thankfully the fires are on the other side of my state and I live in the state capital area, so wildfires are not too much of a worry. But I am praying for my fellow Washingtonians caught up in all of it.
Dan – It’s great to see a response from you. I’ve read so many of your posts and have great respect for you, and I owe you a big thank you for the help!
And now that I think about it, you probably gave me the idea of the safety systems
The rear-end build took me about a month to finish. (It was my first differential also) I took like 3 weeks off work to get it done, so thankfully I have come to adore the 4.10 gears. There is nothing like the feeling of 4.10s and 24” tires so I find that I am going to build the car around that no matter the drawbacks. Like no freeway driving for me and maybe a handicap on the drag strip. Eventually I may dig into it, but for the foreseeable future it’s the 4.10s for me. If I could ever find the unicorn 7.25 Sure Grip that would be great though.

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1969 Plymouth valiant 225

Not sure why you think the records for "D" nitrous is incorrect. The classes are set by weight, and assuming a 225 engine. The rules state "if running the 170 engine, the car drops to the next lower class".
If you notice, I usually run the 170 engine. When I ran my 66 Barracuda it actually would have been in "E" nitrous, if there were such a class.
My best ever time with my Barracuda with a 170, was at Gainsville dragway on a "street legal" night. Went a 12.905 @ 101.85 mph with mufflers, and slicks.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Too bad the googlesheet link/file is broken. I'll talk to Ryan sometime and get him to fix it.

What I see on page 22 of the "Records" thread is 9.39 sec and 74.152 MPH for D/N. Those should not be too hard to beat, but you will not be falling off a log and will need a substantial motor and/or N2O shot (75+ HP?) in that street Valiant.

Lou

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Home of Slant6-powered fun machines since 1988

Spend time and money on head porting and larger valves. 1.70/1.44 minimum. 1.72/1.50 SB Chevy valves work well, but there are many more options these days. I would go for 10:1 compression and a bigger cam around 250 @ 0.050" for a streetable (but somewhat ragged) combo. Oregon Cams regrinds are great and I can recommend a profile if you wish. You will likely have to add weight to make D class.

Lou

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Home of Slant6-powered fun machines since 1988

He is already aware of the issues with Google and the links. He is working on it

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Charrlie_s, in no way did I mean any disrespect. I apparently need to read the rules again. I apologize for my ignorance. Your record is even more impressive—wow!

Dart270, I’ve done quite a bit of research on the absolute hill I’ll have to climb to get to any of the records, but I am determined. Now when it comes to nitrous and cams I start to fall off a bit, specifically for these motors. From my understanding a 226 duration Oregon Cam grind I’ve been looking at would make my operating range 3000-5600-ish (grind number 1416). Am I thinking about something the wrong way?
And the way I’ve decided to do this is hopefully somewhere in the 200-220 hp NA motor, then whatever it takes the rest of the way on nitrous.
I’ve decided to use the Wisco Pistons but i dont want to run a long rod set up so im thining -.100 off the block and -.90 of the head to get me to about 9.5:1 because the compression height of their pistons are so small compared to the stock Pistons. Of course, with the variation in the blocks and the heads it’s gonna really be up to my motor how far i go.

I did use the CAT scales and the car was 3100 so I am planning on adding some weight to the back

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1969 Plymouth valiant 225

If you want to use stock rods (why not Molnar?), then you will want a different piston than the Wisecos. I have domed forged pistons from an ICON group buy that will allow high comp without lots of milling. I can sell you a set. You would need to mill more like 0.300"+ to get high CR with the Wisecos.

Slants like longer duration cams than many motors. 226 @ 0.050" is fairly small if you want to make good HP.

Lou

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Home of Slant6-powered fun machines since 1988

I didn't take any offense about your post. I was just pointing out about the 170 rule.
Who ever you talk to about grinding a cam make sure you specify "nitrous". In general nitrous motors like more exhaust duration than NA.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Dart270- as far as not wanting to use a long rod set up ive already milled the head and block .05 and i am scared the pistions would be proud of the deck and from my crude math it most likely would be. Also im hoping to dive the car to and from the strip and car shows so pump gas is preferable. As far as your domed pistions are concerned I would be very interested but am 4-6 months from being able to put $ into the car (out of curiosity how much do you want for a set, pm me) so depending on the specs im interested. Wiseco pistions have a compression height -.140 from stock so i figured if i take .100 off the block and .09 of the head id be somewhere in the 9.5:1 area assuming the block and head is the factory specifications which we all know they’re not but im ok with all the way down to 9:1
As far as the cam im only going to the 1/8 so moving the peak power futher in the rpms would force me to cross the traps in second gear but maybe I misunderstanding Cam duration when it comes to these motors if i assume 80 mph in the 1/8 with 4.10 gears and 24.5 inch tires im runnig at 4600 rpm ish so even the 226 is more then i was thinking but as i said i dont know how cams act in these motors.

The engine Masters episode Steve’s slant made 215 @4900 with a 220 duration at .05

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1969 Plymouth valiant 225