cruiser
Well-Known Member
Greetings MoBros and MoGals: As promised, here is my third and final chapter of Part 36: Dusty's new motor. As you recall, chapters one and two covered the details of the renewal of the 1974 slant six motor that I acquired, which came out of a 1974 Dodge Dart. The Dart motor is identical to the one that originally came in my 1974 Gold Duster. As a reminder, the original Duster engine was replaced in 1988. When I bought Dusty in April of 2019, she still had this replacement engine, which ended up failing in the summer of 2024 after roughly 115K miles.
Last week we completed the installation of the rebuilt Dart engine. The only components that we kept were the block, head, crankshaft, connecting rods, intake and exhaust manifolds, carb and steering pump. The intake/exhaust manifolds by the way, are factory original to the car. I wanted to keep something from the original factory build under the hood - preserving the "soul" of the car, to my way of thinking. Everything else was new. This was a stock rebuild - no upgrades to anything. And yeah, a lotta guys would have upgraded things, put a different carb and intake on, or maybe even gone for the full Super Six build. But this isn't in keeping with the original intent of my car, which was to keep it as factory stock as possible. Anyhow, in went the Dart (now Plymouth) engine and I couldn't be happier. Here are my driving impressions as I put a bunch of break-in miles on the motor: The rebuild was expensive. I've never personally rebuilt an engine, and I wasn't going to try at my age as I'd just royally screw the whole thing up. So I was okay with going with a really good engine builder here in the Minneapolis area. Sadly, there aren't many people out there who will tear into a slant six anymore, and the rebuild will cost you as much as a V-8 rebuild. I didn't want to buy one of those crate rebuilds from North Carolina. I had a really solid core with good date codes to work with. I wanted to know exactly what went into my motor so that I knew we were starting from a known rock solid engine. I was able to defray some of the cost by doing the unskilled labor at the shop, which helped a bit. But like anything in this world, you get what you pay for. The attached photos show Dusty's new engine, and it looks like a little gem. We took great care in getting every little thing as stock as possible, although a sharp eye will find a few non-stock items such as the master cylinder. Note the attention to detail in the factory style spring clamps on the hoses and crimp clamps on the fuel filter. The modern internals are hidden inside the engine, of course - hardened valve seats, better pistons, etc. The final three photos are of the exterior and interior.
So how does she run? At idle, this engine has the classic "sewing machine" sound and is absolutely smooth with a lovely exhaust note out back. At highway speed, it's sorta loud - which is to be expected. Acceleration is about what you'd expect out of a slant six, and MPG on the new motor is still to be determined. Overall, it definitely runs better than the previous engine which had terrible compression and leak down values, and wouldn't idle.
So there you have it - the story of my new motor in three chapters. Overall, it took about seven months to complete. My final observations: This was a lot of money (please don't ask!) to put into a car that doesn't have much value. I always wanted a very stock Duster because it would be just like my first car that I bought in 1977 while in college. Now that I have it, with the right engine that will be rock solid reliable for good, I can enjoy it and will never have to buy another Mopar. This car will outlive me, and one day in the future someone will be able to examine it with a fine tooth comb and see how Plymouth built their automobiles in October of 1973. Thanks for reading and be well, all!
Last week we completed the installation of the rebuilt Dart engine. The only components that we kept were the block, head, crankshaft, connecting rods, intake and exhaust manifolds, carb and steering pump. The intake/exhaust manifolds by the way, are factory original to the car. I wanted to keep something from the original factory build under the hood - preserving the "soul" of the car, to my way of thinking. Everything else was new. This was a stock rebuild - no upgrades to anything. And yeah, a lotta guys would have upgraded things, put a different carb and intake on, or maybe even gone for the full Super Six build. But this isn't in keeping with the original intent of my car, which was to keep it as factory stock as possible. Anyhow, in went the Dart (now Plymouth) engine and I couldn't be happier. Here are my driving impressions as I put a bunch of break-in miles on the motor: The rebuild was expensive. I've never personally rebuilt an engine, and I wasn't going to try at my age as I'd just royally screw the whole thing up. So I was okay with going with a really good engine builder here in the Minneapolis area. Sadly, there aren't many people out there who will tear into a slant six anymore, and the rebuild will cost you as much as a V-8 rebuild. I didn't want to buy one of those crate rebuilds from North Carolina. I had a really solid core with good date codes to work with. I wanted to know exactly what went into my motor so that I knew we were starting from a known rock solid engine. I was able to defray some of the cost by doing the unskilled labor at the shop, which helped a bit. But like anything in this world, you get what you pay for. The attached photos show Dusty's new engine, and it looks like a little gem. We took great care in getting every little thing as stock as possible, although a sharp eye will find a few non-stock items such as the master cylinder. Note the attention to detail in the factory style spring clamps on the hoses and crimp clamps on the fuel filter. The modern internals are hidden inside the engine, of course - hardened valve seats, better pistons, etc. The final three photos are of the exterior and interior.
So how does she run? At idle, this engine has the classic "sewing machine" sound and is absolutely smooth with a lovely exhaust note out back. At highway speed, it's sorta loud - which is to be expected. Acceleration is about what you'd expect out of a slant six, and MPG on the new motor is still to be determined. Overall, it definitely runs better than the previous engine which had terrible compression and leak down values, and wouldn't idle.
So there you have it - the story of my new motor in three chapters. Overall, it took about seven months to complete. My final observations: This was a lot of money (please don't ask!) to put into a car that doesn't have much value. I always wanted a very stock Duster because it would be just like my first car that I bought in 1977 while in college. Now that I have it, with the right engine that will be rock solid reliable for good, I can enjoy it and will never have to buy another Mopar. This car will outlive me, and one day in the future someone will be able to examine it with a fine tooth comb and see how Plymouth built their automobiles in October of 1973. Thanks for reading and be well, all!
Last edited:
