1971 Duster 360/727

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71DusterSwe

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Warning for wall of text, if you dont like to read just scroll down :)

Hello, I introduced myself some time ago and was going to make a little project thread about my Duster. Never got that far though and now I came in contact with a guy from Sweden who also hangs out here so I figured it's better late than never.

I am 25 years old and I have some experience in working with cars, rust repair, electrical and such, although I have little to no experience with taking apart or putting together engines.
So this seemed like a great project for me to learn more about that.

Last fall i got to know about a Duster with slant 6 and a 904 trans for sale in Umeå, about 25 swedish miles away from me. At the time I had a 78 Camaro which had been really abused by its previous owner and I still had plenty of work left on it.
I called the guy and he said that a 15 years old boy had called several times but couldnt make up his mind, so I just said that I wanted the car and I went to get it as fast as I could :p

We drove there and it was kinda cold outside, test drove the Duster for maybe 2 minutes, paid and went home. The heater core was not installed until the night before we looked at it, and the seller had just put it in its place with some zip ties. It wasnt really a warm drive home but the car ran great.
Except for the awful smell of ammoniak, cat piss, boiling trans oil maybe? We stopped several times when the smell was too much, but we couldnt find the problem.
Apparently a cable to the voltage regulator had come loose, so it overcharged the battery making it boil. It had also taken over 40 liters of gas, and when we filled it up back home it leaked large amounts out on the ground, through the filler neck.

Enough about that. The Duster has plastic front fenders, 8 3/4" rear axle, disc brakes up front and drums at the rear. Interior was okay, but needs some work. Luckily my mother in law does great upholstering. The paint job looks good from a little distance, im not gonna do anything but repaint the back lid.
A little rust in the rear fenders, no big deal though. Seems like its in good shape rust wise at least.

The car got parked in my fathers garage, he has a pretty large tractor garage with good storage.
I started looking for an engine and just stumbled upon a 74 360 which the seller said was in great shape. He wanted about $1350 so I obviously (being a swede and all) bargained and got it down a few dollars and he also threw in an edelbrock perfomer intake. The engine did not include any ignition stuff, no starter, no generator and such.

I worked on the Camaro almost all winter, ordered some parts and started taking apart the engine this spring.
It was really dirty and I was just going to change seals and install a new cam.
When we got the heads off, the top of the pistons were really rusty. You could feel the scrathes in the cylinders with your fingers. We also saw after getting the cam out, that the cam bearings were cracked and the cam itself had pieces broken off off it.
We decided that it would be best to take the pistons and crank out of it just to see how everything looked.
I tried cleaning the pistons but they were damaged. The crank was scratched, main/rod bearings were junk.
Basically nothing were in good shape. I contacted a company and turned in my heads, block, pistons, rods and the crank.
The crank needed grounding, 0.010 and 0.020 i think. The cylinders were also kind of bad so they needed to be bored 0.030 and honed. They said that the block was really rusty, so it must have been stored outside for a very long time.
Then they checked the heads, original x heads which the seller said was one of the best heads for porting and stuff. They were cracked, and the company suggested not to spend the amount of money needed to get them in shape and instead they offered a set of engine quest aluminum heads.
I was already up way over my budget, so I said no to the heads. Stupid..
I still haven't found any heads, and sometimes it takes a couple of months to get stuff from the states.
Oh, the engine company has had my parts since April, and they are still not finished.
I calculated a bit and I think im already in about $5-6000 on the engine and its not even finished or assemblied.

Engine specs should be something like this when its finished:
Block, bored 0.030 over
Original crank
Speed Pro pistons 4.030
Comp cams 20-224-4
Holley 650 DP
Edelbrock RPM intake
Hopefully some aluminum heads, otherwise ported j-heads with the larger valves

Paired with a stronger 727.

I hope I didnt bore you too much, but here comes some pictures.

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These are the seats that my mother in law fixed for me in the Camaro
 
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Yea man! Looks good. .030 for an overbore is ok and fine. Which speed pro Pistons did you get? I just did there hyper-U slugs.

Also, the "J" heads are basically the same as the X heads only with normally seen smaller valves. They will port out very well. There should be no problem making power with the J heads. I have run in the 12's with stock J heads. It takes a good bit of a heavier cam and more gear to do so verse a ported head. But it is cheaper.
(Oh! Camaro seats look really good.)
 
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These are the H116CP slugs. Purchased as a piston and ring set inexpensively together. Costs more purchasing separate.
 
Great! Love all the pictures and story. Keep us updated with progress, and more pics!
 
Thanks guys.

The pistons are the same as you have.
I was in a bit of a hurry when I got the car, so I didn't take much pictures outside of the garage. I'm hopingto get it out for a test drive at least, before the snow comes.
Never assembled an engine before and I still have to shorten the drive shaft, check my engine mounts and stuff.
It will be orange, though ;)
 
A very good book in which I have assembled several engines from is the simple "How to rebuild your small block MoPar." You will have to change some of the values around if you use aluminum heads and headers since there values are different. Also with the bolts or studs you use in place of the OE equipment.
In an example, Edelbrock states to use there bolts to attach the heads at *** torque value. Not the OE value.

With those Pistons, I set mine at a zero deck height. It took a .018 deck milling to do that. It will work in conjunction with Edelbrock heads. Compression will be adjusted with head gaskets for the cam used. Bigger the cam, the thinner the head gasket. ;)
 
Looks great, and your story was very interesting. Looking at the pic of your 360, you will also need an oil pan. The oil pan that is on the motor in the pic, is for a pickup truck or a van. You need a center sump oil pan, and a 360 oil pan is different than a 318/340 oil pan. They look the same, but a 360 pan has a larger opening at the rear, because the rear main cap is bigger on 360's. Keep up the good work!
 
Cool story and nice Duster! It gets expensive doing these cars in Sweden for sure. Good luck! I'll be following your project.
 
Rumblefish: Yeah I have that same book I think, also have the "How to build big inch small block mopars".
I dont really follow the "zero deck height", do I have to modify the heads to fit those pistons?
Jdmopar: Oh thank you, I will be on the lookout for another pan then.
Trebor: Thank you, it sure does get expensive.

A little update, my sister has a very sick child so we went to see them at the hospital in Umeå where I also have my engine at. They were done with the block so I took that home and also took my cracked heads.
I cleaned the heads a little more and tried to find the cracks at the exhaust valve seats, it is two really small cracks which I cannot feel with my fingers. Just ordered a new phone so I will take some pictures and maybe you can tell me if they really are unusable or not?

I am also wondering if an ordinary starter will fit with Hedman headers? Another user from Sweden has one for sale. Mini starters are really expensive here.
Also how do you see what torsion bars you have? Here in Sweden you have to change them to be able to register the car with a v8, and I dont know if they are changed already.
Thanks in advance
 
It's stamped on the ends of the torsion bars. So you should be able to see it on the end facing the rear of the car.
 
My starter fits with my cheap low hanging long tube headers. All the cheap headers are basically the same I believe.
 
Took the block with me to work and drilled out some of the water channels, cleaned it up and sprayed it down with 5-56 before placing it in a plastic bag. I think I broke my back in the process too :p




The machine shop guys said that this was a little bit sad, that all the rust didn't go away. Can it really have been that bad? I mean, 0.030" is pretty much to bore out
 
Not much has happened, I have 0 motivation for the car.
Anyway, I called a guy that had some heads he wanted about $1000 for. He will do all the work on them before shipping them to me. He was talking about the valves and said it was better to get 2,02 + 1,6 valves instead of 2,02 + 1,8. Is this true ?

He also said something about that I should get adjustable rockers because the Engine is not original and he did not know how much to Mill the heads to get proper pushrod/valvetrain function.

I checked on ebay and that was some expensive rockers+pushrods and I have no idea what to choose either.

Im having trouble relying on people more and more so Id be happy to get some response on this, he might just as well try to fool me.

I am finally getting the rest of the parts back from the machine shop as well, ive waited since April. Hopefully this will give me some motivation to test fit Engine mounts, block and headers.
Snow has started falling too, so I wont get to test drive until spring.
 
Motivation is hard when yyou spend and spend and feel like you don't make progress. I can't chime in on the adjustable rockers, but other people here will help you. IF you need them I think that I have some ball&cup pushrods to sell you for a reasonable price. That is, if you need them etc.

I basically never turn to Swedish forums for advice. I always go here. If you ask an intelligent question on here with all the info needed in the question, you will get the best help I have ever experienced on an internet forum. Make plans for progress, go here and tell them, others will chime in. You will star to make progress and motivation will be back. Kör hårt och lycka till!
 
Hey! Sorry for the delay in response.

"Zero deck height" is when the piston is exactly the same height at the top of the block, where the head sits. Those pistons that I showed are a flat top that have been rasied up in there height a little bit more than a stock piston. For more compression.

Placing the piston at a zero deck height would more than likely require some machine work to the deck.

No head work would be needed. Placing the piston this high allows the compression ratio to be raised even further. In most cases, it also allows a good quench area. BUT! The compression ratio can get to high IF there is not a good enough octane available and/or the cam is to small.

Placing the piston at zero deck may not be a good move for your planned engine set up. I normally do this to my engines that are planned to be a bit more energetic.

On the cylinder head valves, a 2.02 - 1.60 is what your after. I have never seen a small block with an exhaust valve bigger than 1.65.

Adjustable rockers on a performance engine is an excellent idea. You can order custom length pushrods later. Getting the rocker geometry is a critical part of not just engine performance but also long life for the valve & guides.

On getting parts from e-bay, I tend to shy away since if it is not brand new, I could be purchasing other people's junk.

A Good adjustable rocker arm could come from Hughesengines, Comp Cams, crane Cams, Harland sharp, just to name a few. Crane has mechanical rockers as well as roller rockers.

Edit! Thanks Trebor! Your mention of a cup or ball adjuster is something I forgot. The pushrod will have to be made to match the adjuster. Which is no big deal.
 
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Trebor: Yes you are absolutely right. It's hard to keep things apart as well when you are new to this and everyone you talk to says different things :p
Yeah sure i'll let you know if I need them. Tackar och bockar :)

Rumblefish: Hmm okay, good to know. But how do you set the piston height? Do you mill off some of the top end of the block?
You are right about the valves, I remembered wrong. I'm still struggling to remember all these numbers haha.
The guy who sells these heads was gonna mill them, sandblast them, mill the valveseats, put in new sandblasted valves and put in copper sleeves. Should I go for this head setup?
And can I use these ball and cup pushrods that Trebor has with an adjustable rocker set? And can you recommend a good set for me?
You are right about ebay too, I just look at new parts from companies :)

Got my parts today as well. They even sent back my old pistons, shafts and everything. So now i've gotta go and dump them.
Almost feels like christmas :)
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Edit: Thanks for the fast responses as well, really appreciate it
 
You set your piston height by way of a few simple ways, but to keep it simple, once the piston is on the rod and installed on the crank in the block, the machinist will measure the distance from the top of the piston to the top of the block. Then cut the top of the block.

Other ways are order the piston with a change in where the pin sits or the tops thickness which is not such a good idea in 99.9% of engine building and then there is rod length. The stock rods are 6.123 inches long. You can have this changed. Does can be purchase in 6.125, 6.2, 6.3 or shortened smaller.
Look under "generic rods" for this.
But now where getting in deep instead of Simple.

On the heads, IF this guy that is doing the work an excellent machinist and KNOWS what he is doing, then it might be a good idea IF the heads fit the target goal. And that I don't know. Your target goal is?
I just mentioned several good places to get good rocker arms from.

I currently am running Comp Cams roller Rockers and on the next engine being built (now) is a set Of Hughesengines roller rockers.

The comps I have had for a long long time and everything worked and aligned really well in my Edelbrock heads.
 
Rumblefish: Alright I think I got it now.
I have no idea if he is good at what he's doing or not, I only know that he's had the company since -91 :p He also said that with the bigger valves you lose torque and you need to rev higher which is bad with a cast iron crank.
Don't really know what my goal is either actually, im not gonna race it or something like that but I want a "fun" street car.

I will check those rockers, but what is the difference between roller rockers and ordinary rockers?
 
It's the tip of the rocker. The roller rocker rolls her the top of the valve stem freeing up HP. There actual ratios are very consistent. Normal ratio is 1.5. A 1.6 is available.

Ordinary rocker, as in the OE (Original Equipment) are stamped steel parts that rub on the valve stem costing HP. Also the OE rockers are very bad in there actual ratio. Sometimes coming in as low as 1.3 instead of 1.5.

I am not totally on board with a larger 2.02 valve losing torque on the low rpm.
The smaller valve will keep velocity up. But give up HP up top. There are also a lot of other factors that will give up torque on an engine than a 2.02 and be more than a good bit more serious in loss. Poor tune, too large of a carb, wrong cam, low compression.

Any engine I'm building now gets a 2.02. My cast crank engines run mid & low 12's for the last many years. There's more than a few guys here producing well over 450 hp on cast cranks.
 
Rumblefish: Alright got it. What difference does the ratios do?
I decided to not buy the heads, he had other people who were interested and it was going to be more expensive than he thought. He didn't really want to "destroy" the heads by putting in bigger valves either. His point was that you lose too much torque in the lower rpms like below 2500rpm.

I also asked him about my heads and apparently they're not X heads but just usual -75 360 heads
 
Just to chime in my experience. I have a solid cam and adjustable rockers. I wanted to go that way at that point. If I'm building another engine I will probably use a nice hydraulic cam that makes torque down low, instead of the high revving engine I have now. For a mostly street driven car it just makes more sense. I would also not have to adjust the rockers every now and then with a hydraulic cam.
 
Yeah I guess I will be driving around much åt lower rpms too. Don't know what the stall is on my turbine either.
I think the cam i have is hydraulic, no?
 
Yes, I missed that earlier. It's a nice hydraulic you got there. I have a 10" 3000 stall converter on mine. It's fun, but a little bit nuts to have on the street to. But my little mill needs some help :)
 
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