Mopar 273-4bbl Combo
 

I bought a 1966 Dodge Dart off a local Stock/SS racer in the DFW area. It's pretty much just a roller at this point, but it has a cage already in it. My plan is to run it in Stock, natural K/SA at 13.47 #/HP, probably drop down to L/SA. So far, just have a couple of blocks, cranks, picked up some 920 heads at a local swap meet, bought an LD4B and a 1967 273 AFB off Terry Dye. I made a post over on Moparts about valve selection that works in these heads, and some body suggested I put a post over here. So, if anyone has any info they are willing to divulge (buy this, don't buy that, you're a loon for running a Mopar, etc.), please post or send me a PM. Thanks.

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I would contact Matt at victory engines he run one in ss and sure he could point you in the right direction. hes in Marshall mn

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I used to run a 340 Mopar. When I saw the ports on a 273 I couldn't believe how small they are. If I were you I do some serious research before you commit and waste money on a weak combo. In Stock Elim., don't see it working out very well.

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The Bushmakers out in D6 seem to have figured it out...Angela runs K most of the time and is up on the sheet consistently.

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Jim you are correct. Angela's car runs very well. It is a 65 Valiant 2dr. sedan

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what combo did paul wong run?

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Was the Chrysler Marine 340-4 Super Bee engine with the 4bbl steel manifold, the same as that motor. We have one laying around somewhere.

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may i ask, who did your 2 barrel carb?

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Maybe i did not make my question clear. did you modify the 2 barrel carb yourself or have a third party do it for you

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X2
Matt Steen @ 507-532-2436

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Is Matt the guy with the white Valiant that runs in SS/K? I think I saw him a number of years ago at Ennis. Not sure how he would like me calling him for info when I'm having a friend/machinist/engine builder in Tampa build my stuff. I guess the worst he can say is to bugger off.

I was sort of hoping to build a dime rocket, or at least a quarter rocket. It does look like Bushmaker's got it figured out. Yes, the ports are tiny, about the size of 302 Ford heads (at least the 1960s stuff I've seen). I thought it would be a good entry into Stock. It doesn't need to fly and compete with the CJs, COPOs and DPs. It would be nice to qualify for divisionals and the national event at Ennis and maybe Houston or the next nearest track.

Thanks to all for your responses and information.

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That is a VERY good combo. One of my good friends had to run them at Vegas in class, and his car is by no means a donkey. He told me he had NOTHING for them. Bushmaker has done this for a year or 2, he knows whats up. ;)

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can anyone suggest a cam for the 2 barrel combo?

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I finally got in touch with Matt today. We had been playing phone tag for a few days. He gave me the advice of using a 318 block (he preferred an X block, not many of those around with the unbored 3.91" bores) and sleeve it down to 273 bore sizes. I think I agree as I was talking to my machinist in Tampa and he did a quickie sonic check and got wall thickness in the .160"-.180" range with standard bore blocks. It looks like Melling has some 1/8" wall sleeves that would fit in a standard bore 318 that would get them down to NHRA specs. He also seemed to prefer the 302 heads over the 920 heads. He is building a 273 stocker engine now. Matt had run the 273-4 engine as a stocker many years ago and said it was making around 330-340 HP back then.

So it looks like we either hard block the 273 blocks or sleeve a 318 down.

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PM sent. Call me

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Back in high school, 1968-1972, two Mopars were around that were somewhat overlooked in the days of 383 and 440 Roadrunners,GTX's,Challengers, and other brand big block cars. One guy had a Dodge Dart GT, 273,4barrel and a 4 speed, and he never ceased to amaze everybody with what that little pocket rocket would do. He beat a lot of unsuspecting cars with it. Another small block fun car was the 70 Duster 340 with a 4 speed. that would give 350 Camaros and 396 Chevelles fits. It's not that I don't like Chevelles, I'm up to my eyebrows in them, but some of these other combinations are worth looking into. The Bushmakers prove that every time they show up.

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You should call Rob.



http://d2ydh70d4b5xgv.cloudfront.net...456f0e81f1.jpg

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I've known Rob for many years. He drove my old Joe Ralph Thompson AWB Plymouth when a mutual friend had it. I bought that car from Fred and I had posted photos of it and Rob saw it. He described it as a scary car with the straight front axle and regular gear box. I've never actually met Rob in person, but have exchanged e-mails for about 15 years. I had that article in a Hot Rod magazine when I was a kid. I guess the Mopar world is small enough where you get to know the other Mopar guys. Rob has a mid-1960s Impala that he's running with his son.

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I had a friend who,s dad owned a 68 dodge dart,273 4spd,hub caps,14 inch bias ply green with black vinyl roof,we would take it out after his dad went to sleep,pushing it down the road,We raced a few guys with the dart and that little screamer being bone stock was impressive,good combo but like Paul said get your wallet out

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Boy, everyone is telling me to get the wallet out. I think I have $40 in there or maybe a bit more. It looks like the rods and pistons might be some of the big ticket items. It looks like Melling has some 1/8" wall sleeves that would reduce a 318 stock bore (Ø3.91") down to the 273 range (Ø3.66" or so). I'm thinking using Hardblok in the wimpy 273 blocks will be a cheaper way to go. The Hardblok is about $100, sleeves are around $20-40 each, plus machining. I'll see what my machinist/engine builder wants to do, but the Hardblok looks like a less expensive way to beef up the thin cylinder walls. I wonder if the later 273 blocks had thicker cylinder walls?

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I'm slowly working on this same combination for a 66 Barracuda.

You need to keep in mind that the sleeve will need a step to retain it in the parent bore. You can't stick a 3.910" O.D. sleeve into a 3.910" bore. There will be nothing to support the sleeve. You will need a sleeve with enough oversize beyond the parent bore dia. to allow an adequate step to register against. I have not found any straight sleeve with enough wall thickness to do this. In this case, the only way to do the sleeving correctly is to get a set of flanged liners and counter bore the deck for the flange.

A custom sleeve will be an expensive investment along with some fairly substantial machining costs but in the end, you will have a block that will maintain it's bore size for many re-hones.

I will have to sonic test the 1967 273 block I have to see what it has for thickness.
In the mean time, I am saving up to purchase the pistons and maybe sleeves.

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I did catch my engine builder while he was taking a break at the beach on the east coast of Florida. He was thinking along your lines but using a 340 block and get custom sleeves with the flange as you mentioned. That would be really stout cylinder walls for a 273 size engine. He said he did that many years ago when he ran his Colt in MP with a 280 CID (3.935" bore, probably the old 2.96" stroke crank) with W2 heads. I wasn't sure how big of a step was needed at the bottom near the main webbings.

I think I will start with a 273 block with Hardblok on the first go. I don't want to spend a ton of money on this project. The idea is to run quick enough to qualify in Div. 4 divisional and national events here (don't plan on going to Indy).

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James,

I also love the combination and wish you well with your build.

Sleeving a 340 X block would be the ultimate, but very expensive (if you can find one) Hardblock in a 273 is the way to go on a budget.

Also speak to Dean Oliver about a carburetor.

No disrespect to all who have offered their advice but Paul Wong is the guy I would consult.

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I have looked at this combo for a while. What style header are you going to run? There were some fender well headers for them but choices are limited now. The primary tube diameter being to large from a 340 is a problem. Luckily for you guys I have the stahl fixtures & masters for the early a cars with a small block 😋. The 66 valiant sedan in ss looks like the best combo to me. The problem is committing that much money to that engine program. With a x block & Honda rod journal, killer heads & intake, and lots of rpm. The package is light enough to be a killer! But what old killer package is cheap? None.....

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Thanks for the info on the carb. Matt had mentioned Deano did his carb. Now I know he meant Dean Oliver. I have some 340 blocks, used to have a TA block, but sold it to a restorer in Houston many years ago. I'm going to go with the Hardblok. Thinking about using K1 rods and CP pistons. Not sure about what bore size and what rings? Anyone make spacers to fill the 5/64ths groove with a 1mm or 1.2mm top ring?

The Edelbrock head looks like it might be a good future upgrade with only a 5HP hit. It will add some 68 pounds to the car, but with my fat butt driving I think it will be heavy already. I wonder if Edelbrock sells the head without the valve seats installed?

I see that TTI, Dougs and Hooker makes headers for the early A-bodies. I didn't see anything on the Stahl site. I think they are all 1-5/8" primaries. The TTI looks like it has the best plug access. All are $600-$900. No cheapie headers for that combo.

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what is your definition of cheap?

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$600-900 is cheap for headers in comparison to others out there. The west coast stainless headers are $ 3400 just an FYI. You won't see any headers on stahl' site. All the fixtures were sold. I bought all the Chrysler fixtures along with all the collectors stahl had. I'm not trying to sell headers on here just saying that may be an option for you. I allready have one person that contacted me about building a set. I think I may have some 273 parts left if you need some. I would like to see this combo out there, I think it would be cool if it had a stick behind it also!

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as i get my project closer to completion i will call someone for a set, but my question was on the whole car, do you consider 15 to 20k cheap?

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Yes I think that is cheap to build a car, I run a 70 cuda in super stock, by all means it's not a cheap car to build. I do all the work myself also except engine & trans. You can't build a stocker motor for what you are saying. Average competitive stocker motor is 20k

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and that maybe the reason, we are seeing less and less new cars

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I've seen Mark's SS headers. Nice stuff, but out of my budget on the first go around. I'm hoping the 273 will be half of that $20k or less, preferably less. For an engine that will make about 325 HP more or less, I can't see putting $2k rods in it. I think I found the Ross pistons for around $800, hard to say what the ring pack will cost? My idea of cheap headers is the $200-300 ones. They used to make some 1-1/2" primary ones for trucks, but I think they are all 1-5/8" now. I'd like to dyno test with the cheap headers to figure out what size I need before popping for the mid-range headers (sub Performance Welding, above the cheapo headers).

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did that ld4b edelbrock come from the factory ?? thought it was a cast iron intake

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I talked to Kevin at Total Seal and they can supply spacers and 1.2 mm. rings for bore diameters that would work. He suggested that he work with whomever makes the pistons (CP or Ross) to insure the ring groove dimensions are correct. I did get prices from both Ross and CP and the Ross are a little cheaper. The pistons will have to be made to a specific bore size due to ring availability.
I second Frank Castros on consulting Paul Wong. I have only had a couple of PM's from Paul but they had some very good info. He has had more experience with 273's than anyone!

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It got added to the engine blueprint specs, not sure when. I'm grateful as the LD4B was easier to find than the flat iron intake.

I think I found some 1.2mm rings in the 3.66" range. Good to know they have the spacers already. I'll check into it. I e-mailed CP to see what their pistons costs. My machinist thinks the Ross pistons are too hard (brittle?).

Paul has sent me a PM. I haven't got much detail yet, but I have plenty of time.

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the amc's had the r4b also but it got yanked a year later ,,,, just seams odd

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I think this got approved because of the d-dart, but I could be wrong

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Paul Wong is the bomb, he is the National Performer award winner . Angela Bushmaker also has a bad AZZ 273 , she runs extremely fast.