225 slant rebuild for more power

Slant 6 Engines

  1. Garrett Hurley

    Garrett Hurley Active Member

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    I’m 17 years old and taking auto classes through my school. Tomorrow we’re pulling the 225 slant out of my 64 valiant wagon. I need some more power out of it and don’t really know where to start. Going to see how much it will be to send it out to the machine shop but would rather not go through that. I’m thinking the 2 barrel manifolds and carb if I can find those and some new valve seats and what not. It runs good how it is but need to do all the gaskets and manifolds anyways got leaks everywhere. Looking for your guys recipe for a more powerful slant that is still a good runner. I’m located in LA if u guys know any machine shops in so cal.
     
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    • 65 Dartman

      65 Dartman FABO Gold Member FABO Gold Member

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      First off, welcome to the forum. There’s a wealth of knowledge here that the guys will be more than willing to share with you. The 2 barrel would be a good start. A larger exhaust from the manifold back would also be a great upgrade. Since the motor might be going to the machine shop, measure how far down in the hole the pistons are - I would guess at least .175. That leaves you plenty of room to shave the head and/or deck the block which is going to increase the compression. Just these mods will provide a decent boost in power - not V8 style power - but a noticeably increase.

      i have a 65 slant that got bored 30 over, the block decked 90 thou and the head cut 10 thou. With the cam I ordered, I suspect it will run pretty good with my triple Weber’s, Headers and my 4 speed.
       
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      • Slantsix64

        Slantsix64 Well-Known Member

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        Pull the head, Mill it .100 thousands if it has never been touched, that will get you to 9:1 area But measure piston deck height to get in the ball park and cc heads,

        clean up the head while you are at it carbide bit off amazon less than 20 bucks port it out a bit just smooth out any casting flaws dont go crazy add 340 springs,

        get some split exhaust manifold or run a 2.25 exhaust head pipe under you stock manifold

        recurve that distributor swap over to electronic ignition

        super six it but get ready to redo the whole linkage and kick down also need a early v8 gas pedal assembly

        Send your camshaft to oregon Cams get a regrind or pick out something for torque cause you got a heavy car.

        Should have a nice cruiser while maintaining MPG and adding HP
         
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        • RustyRatRod

          RustyRatRod Weenie idiot loser. FABO Gold Member

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          If you want new valve seats, you're "gonna have to go through with that" to the machine shop. That said, the slant can be pepped up, but it will never equal a V8 for power.........without forced induction or nitrous. If you can live with that, then have at it. Staying naturally aspirated, you can probably see one horse power per cubic inch with mods such as bigger carburetor and intake, hot camshaft and headers.
           
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          • MoparMike1974

            MoparMike1974 FABO Gold Member FABO Gold Member

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            Also, some big improvements on the street can be had by mods other than the engine. Put some decent gears in the rear, nice open exhaust and shift kit the trans. Slant cars can be really fun to drive and you get the reliability of the slant.
             
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            • my68barracuda

              my68barracuda Well-Known Member

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              A ‘64 Valiant wagon is a very cool car.
              While the engine is out for improvements, invest some effort in proving the brakes. Those old school drum brakes are no match for the stopping power of the modern cars that will be on the road with you.
              Inspect the brake lines, replace the steel and rubber hoses as necessary. I have had good results with the steel lines from Inline Tube. Up grade the master cylinder to a modern 2 chamber unit and look into disks for the front. Good luck with the car and make it your own.
               
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              • valiantwagonguy

                valiantwagonguy FABO Gold Member FABO Gold Member

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                A six is a six and never going to give you any real power like a small block V8 unless you spend a crazy amount of time and money on it.At 17 years old I'm guessing you can't do that .What I would do is pull the motor out and just freshen it up with a timing chain , rear main oil seal ,all new gaskets & freeze out plugs .Put in electronic ignition and a good rebuilt carb and use it as it is.Enjoy it and take care of it slowly fixing it up .A Valiant wagon is a very sought after car so enjoy what you have while it goes up in value then sell it when you are older and know more about how to do all this . What you will get from the wagon will give you what you will need for the next one down the road and you will have way more experience and money to build what you want .
                 
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                • JGC403

                  JGC403 Well-Known Member

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                  I have never worked on a /6 so I don't have any first hand experience, but I stumbled on Uncle Tony's Garage on Youtube. He has a couple of episodes on the /6 and has some interesting ideas, I don't agree with everything he says sometimes but I think its a good place to start if you don't have any experience with these engine and take away what information you want. Do a search there are several episodes on the /6. Here are a couple episode:

                   
                  Last edited: Dec 17, 2019
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                  • KosmicKuda

                    KosmicKuda FABO Gold Member FABO Gold Member

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                    Welcome to the club.
                    I completely rebuilt the 225 in my 64 Val because it was locked up when I got it. Following recommendations here I did the following:

                    Milled head 0.080 but you should consider going 0.100. As Charlie says, no downside, big upside. Modern head gaskets are at least 2X thicker than the original steel shim gasket so you'll lose a little compression. I did a complete rebuild so had my machinist install hardened exhaust seats with valve job. I did a little pocket porting and gasket match because it was only my labor, free!

                    Block bored .040 over with Silv-o-lite pistons and moly rings.

                    Sent the cam to Oregon Cam grinders to be reground. Talked to the owner and he recommended 2 grinds and I went with the milder because it's a driver. I'd say it's between 318 and 340 specs.

                    Did a little porting on the stock exhaust manifold and gasket matched, free labor.

                    Rebuilt the stock BBS carb. Advance timing to 10* BTDC.

                    Anyway, it drives great. Never feel a need for more when driving. Best ET was 18.4 secs. Got almost 24 MPG going to Carlisle. Have about 8000 miles on it and haven't touched it.

                    You can do less and be fine. Since you are taking classes, disassemble completely, new timing chain, maybe hone and re-ring, check bearings, oil pump, etc. and inspect everything. Dyno proven that biggest increase in power is going to 2 barrel carb.

                    You need to read this section and check out slantsix.org
                    Disregard the haters who say V-8.
                     
                    Last edited: Dec 18, 2019
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                    • MoparMike1974

                      MoparMike1974 FABO Gold Member FABO Gold Member

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                      Uncle tony is very knowledgeable and has been around the block. Every so often on a rare occasion he will say something that is inaccurate. For the most part he puts out decent videos with accurate information. Certainly better than some of the more commercial channels out there.
                      I like the one with Dulich on there too. Cant remember the other guy off the top of my head.
                       
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                      • Garrett Hurley

                        Garrett Hurley Active Member

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                        Thi
                        Alright couldn’t have asked for a better explanation from you guys. I have a daily truck so I’m in no rush to get this motor going. I’m gonna take it apart and get all the measurements this week It is %100 stock numbers matching which is another reason why I don’t want to put a v8. I do have ac but I couldn’t give a hoot if i don’t have it. Will use my Christmas money to send it to a machine shop. Anybody know any machine shops in CA that will do this. Thanks guys so cool hearing your guys thoughts more helo than I could imagine
                         
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                        • AJ/FormS

                          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                          Couple of Quick questions
                          How much power can a compression boost, a 2bbl, and decent exhaust bring to the combo.
                          And where in the rpm band is it gonna show up?
                          Just asking
                           
                        • RustyRatRod

                          RustyRatRod Weenie idiot loser. FABO Gold Member

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                          What I like about the slant........and ALL straight sixes, really, is they respond RIGHT NOW to throttle changes. Very peppy. I only have the 170 in my 64 Valiant, but man, it's a hoot to drive. I love it. It gets up to speed really quick and you can tell it WANTS to go. It's just a fun little car. I am building a long rod 225 now with the 2.2 4 cylinder Chrysler pistons, big valve ported head and somebody's bigass custom cam, four barrel and headers (MAYBE a ported and hogged stock manifold). Haven't found which cam I am going with yet. Was hoping for some help from a member here who works at Crower, but after several attempts to get with him, I have given up and am going another direction.

                          Slant sixes are very unique. They're from a completely different era, they're archaic, they're DIFFERENT, they're indestructible AS LONG AS you keep oil and water in them. The simple fact of the matter is this. People who say "throw the slant in the ditch and put a V8 in it" just don't get it. You don't build a slant to run fast.......well........a few do. There ARE some really nasty ones out there. Some that run in the 9s. Maybe faster. BUT they are REALLY nasty and not very streetable.
                           
                          Last edited: Dec 18, 2019
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                          • valiantwagonguy

                            valiantwagonguy FABO Gold Member FABO Gold Member

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                            I have a 170 slant in my 65 Valiant station wagon daily driver.I love it. I put an A 833 4 speed from a 65 Barracuda behind it and it's lots of fun to drive.It has a 7 1/4 sure grip with 323's and it responds real well when I hit the gas.I take it on really long trips up to my camp in the Adirondack mountains 400 miles away fully loaded with tools ,camping gear , my 3500 watt generator , chain saw and my kayak on the roof . It's packed to the max . It's an 8 hour ride up and she just does it with no bullshit . Gets around 24 mpg and is as easy to work on as they come.I would never trade my stock little 170 for a v8 . Since July of this year I had her up to my camp 3 times putting on a shade over 5000 miles on her. Never once did she miss a beat .
                             
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                            • KosmicKuda

                              KosmicKuda FABO Gold Member FABO Gold Member

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                              I don't know but I'd bet a bump in compression will help through the whole power band. 2000 rpm seems to be my sweet spot when cruising. I wish I could have driven it "before" for a comparison but it didn't run when I got it. And it runs fine on 87 octane.

                              The first couple drives on the street I found I had to be careful starting from a stop as the right rear tire would break loose. Confession...it was the little skinny 13" tire though. Oh yeah, it's a 3 on-the-tree with 3.23 gear.

                              IIRC, the stock valve lift in my 64 225 was only .375. .375!! These things were built as bread and butter base engines.
                              A fresh engine, a little pocket porting, I thought yeah, it can handle a bit more.

                              Luckily after I got it running I found a complete, barely used 2" pipe exhaust system with a little Thrush muffler welded into it at a swap meet for $40.

                              It's a convertible and people are always talking down at me from their SUV's at traffic lights.
                              3 most popular questions:
                              Slant Six?
                              Pushbutton trans?
                              What year is that?
                               
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                              • dart19666

                                dart19666 FABO Gold Member FABO Gold Member

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                                Haven't found which cam I am going with yet. Was hoping for some help from a member here who works at Crower, but after several attempts to get with him, I have given up and am going another direction.

                                Some people just cant understand that I am in the engineering department. So making phone calls out "Sales calls" are incredible hard since I am mostly on the dyno and spin-tron all day designing new parts. But if you like I can post the in box where you asked the question "One more thAng.......can yall machine a 1/4" wide by 1/8" deep groove in the rear cam journal for increased oiling?" on July 19 2019 and responded a whole three days later with "Yes not a problem. I did that to mine so when i started doing rocker arm testing I did not want to have an issue." On July 22 2019 Sorry for the late response then three days later ha ha ha. It is what it is. If you are referring to a Crower email well I get over 100+ of them a day 90% are sales So if I am in the engineering room for 3-4 days well....simple math will explain that.

                                On to what will help you Garrett Hurley and your engine........The link below is what I have been doing to my Dart "Daily Driver 50+ miles a day in So Cal Traffic" Some of the things that were offered to me on all these threads worked and some did not work. Enjoy the fun. Slants are way up on the cool factor case in point, I won a car show with my POS and was not even parked in the show area, just had the hood up. I like it because it is something different and I have NEVER messed with a slant before so what better way to learn than to try it out for myself. The biggest piece of info I can tell you is, get a wide band O2 sensor, that way you can see what is really going on, Slants respond differently to some mods and the same to others mods. Every engine is different so what works for one may not work for another. Also do not get frustrated, it is a learning curve for sure.

                                1969 Daily Driver
                                 
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                                • RustyRatRod

                                  RustyRatRod Weenie idiot loser. FABO Gold Member

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                                  Man that's really cool! Thanks for sharing!
                                   
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                                  • RustyRatRod

                                    RustyRatRod Weenie idiot loser. FABO Gold Member

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                                    Hay I understand it. But this is the first you've gone into any detail "about that". I can see it's one more load you don't need. I do thank you for your help thus far. Merry Christmas!
                                     
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                                    • dart19666

                                      dart19666 FABO Gold Member FABO Gold Member

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                                      Not a problem, but please you should reread our exchange on the inbox messages. You also have a Merry Christmas.
                                       
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                                      • RustyRatRod

                                        RustyRatRod Weenie idiot loser. FABO Gold Member

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                                        Oh I have. My issue was I was waiting on a return call from the few messages I had left. I had no clue as to how busy you were until now. I much prefer direct communication than email. It's all good though. Thanks again.
                                         
                                      • dart19666

                                        dart19666 FABO Gold Member FABO Gold Member

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                                        Oh you left a Voice mail???? Yeah well that is even worse 99% of those I do not get way too many to filter through........"Read the inbox so this is not hijacked in open form"
                                         
                                      • RustyRatRod

                                        RustyRatRod Weenie idiot loser. FABO Gold Member

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                                        I left several and again, I HAVE READ your responses. You "could have" responded in PM had you wanted to. But as I said, There are many camshaft companies. You did offer to help in the beginning. If you were too busy, you should not have. As I said though, it's all good because I'm not in a hurry. I just like to line my ducks up, that's all. If you want to continue this further, feel free to PM me.
                                         
                                      • 6pakattack

                                        6pakattack Well-Known Member

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                                        Happened upon this on another site I belong to, saw your post and couldn't help but put some info out there for you !



                                        Aussie 4 barrel intake
                                        Holley 600cfm carb
                                        Aussie 6 into 2 headers
                                        High Volume Oil Pump
                                        Cylinder Head (waiting on Frank)
                                        Head Gasket
                                        Intake/Exhaust (Romac)
                                        Offy Polished Valve Cover
                                        K1 Forged Rods and Pistons
                                        ARP Main,Head Studs
                                        Oil Pan and Valve Cover Studs
                                        Double Roller Timing Chain
                                        Romac SFI Dampner
                                        MSD6a
                                        Mallory Unilite Distributor
                                         
                                      • Perseus

                                        Perseus Member

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                                      • RustyRatRod

                                        RustyRatRod Weenie idiot loser. FABO Gold Member

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                                        You don't want a high volume oil pump in a slant. Best to either use a stock volume pump, or a stock volume pump with a high pressure spring, but not the high volume.
                                         
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