Would advancing a stock camshaft on a low compression 318 have any performance benefits? Any one ever advance a stock cam? A little back ground: I bought an early Dodge Dart for a project. My objective is to build a low cost car with decent performance. So far I have the Dart, a 318 and 904 transmission an open 3.55 8.8 Ford differential , a Holley Street Dominator manifold a Carter 500 cfm AFB carb, headers that will need modifications to fit and a recurved Mopar performance distributor.After I get everything assembled and running I will test at the Drag strip hopefully I’ll be in 14s. As time and money allows I’ll install a stage 2 shift kit and performance camshaft. I believe I can get this car deep into the 13s for very little money. Thanks in advance Dan
Dodge along with the others retarded the cam timing in 72 and later. Since the 318 wasn't built for peak performance, it didn't suffer this as much, but this is something that would depend on what year the engine is and the tolerance stacking of your exact set of parts. You will need to check this by degreeing the cam in the engine. There isn't a wide range of stock cams for this like a SBC. No quick and easy 1.6 rockers either, until you get to magnums. When just moving the cam, stock springs are not a major concern, but they should be checked for pressure and installed height. A bigger cam will need degreeing, springs and checking for clearance. Mopar put out a bunch of performance bulletins, but that's 70s tech and most at that time didn't build a 318, they would just grab a 340 or 360. Here is a build https://www.speedyauto.cc/howto/racingcar/engine/201603/234585.html Some newer info https://discover.hubpages.com/autos/Mopar318 A bodys forum has a bunch of low buck racers, I'd spend some time over there. Here's a post from 2011 https://www.forabodiesonly.com/mopar/threads/12-second-junkyard-318.139958/ 2017 https://www.forabodiesonly.com/mopar/threads/318-build-on-a-small-budget.390502/ 2018 https://www.forabodiesonly.com/mopar/threads/big-horsepower-318-builds.470579/ As with any build, the parts chosen MUST all work together. You can't mix a high RPM cam with a high torque intake. The forum has guys that have mixed, matched and done a lot of testing. Since any build is going to be limited by time and money, figure out what you can afford there and make sure you can afford the total before diving in.
Optimizing the whole car might get you into the 13s. It's going to be a lot of little things. Proper suspension setup and alignment, matched converter, weight savings, tire selection and pressures, etc. Most bracket guys are good at tuning, but if you want to get the car going faster with time not money, take a look at the pure stock guys. They have to look original, but optimize every little bit to run better numbers. Stuff like making sure the front suspension is super smooth and straight. https://www.enginebuildermag.com/2022/03/pure-stock-muscle-car-drag-racing-keeping-alive-a-legacy/
Thanks Rod, I’m on for a bodies only, good bunch of guys like here, lots of stuff on 318s mild to wild. My plan is to get the car running with what I have. Before installing the engine I’m going to change the timing sprockets and chain, just wondering if advancing the stock cam will be beneficial ? Down the road I plan on installing a performance cam when money allows, most likely a custom grind to work with what I have. I’ll for sure degree the cam to the grinders suggestions. Things like a higher stall converter, SS springs, LSD for the rear end will be added as I go. I will add frame stiffeners before installing drive train.? Some day down the road I’ll will freshen up the engine, if money allows I’ll build for performance - get the piston up to the deck, after market heads, bigger intake and carb, and cam accordingly. I don’t have to worry about idle vacuum as I don’t have power brakes. Or maybe build a 360 Magnum ? Dan
Good info on the cam, I’d thought it was a “Ford thing”. When I was doing a cam on a 460 I was advised to use a pre ‘70 timing set, pretty sure I used one that was also +\- 4 as well, but still ran it straight up.
Dan, if you are looking for bang for the buck, the small block mopar is 20 years gone. Sure it can make power, but there has been another engine that has replaced it. Something that has easily found JY parts, a strong base for stock to crazy builds, and even forced induction from the factory... To build on a budget, you have to rely on the path others have already laid out. No testing or experimenting, no wild machine work ($$$), no blind alleys, just straight forward research and buying once at the best price. The places that bolt together crate HP long blocks are going to lay out what they use. These combos have to hit a number, have some sort of warranty and be sent out and installed by DIY people. They should provide a parts list that isn't cutting edge, but are proven. They are also a guide to cost. If you can't beat the price, just buy it. https://www.hotrod.com/how-to/7-cheap-small-block-mopar-crate-engines/
There is lot of good stuff out there for a fair price, however my goal is to have this car on the street running safely and soundly for $5000 no more than $6000, so far I’m under budget but have brakes, suspension, steering , interior and paint to go with 2500 to 3500 left. I would love to throw a 400 hp crate or build into my car but right now the money ain’t there so I’m basically building a Junk Yard Dog. lol Dan
Yeh I think you have a more solid foundation as your engine has been rebuilt, your vehicle is lighter so should be easier to get to level x performance. I’m not building a race car just something fun although I planning going to the track a couple or so times a year. Racing legally sounds fun to me. Just shooting for some numbers that will provide some excitement. Dan
I'm saying to use those examples as a guide, not just buy to win. I wish both of you the best in getting them running and running well.
Thanks Rod, you being one of the resident Mopar Gurus I appreciate your input. As I move along I’d like to pick your brain - if you’re willing. I want to get the junk yard dog running and driving and then improve a step at a time like you’re doing with the T having fun along the way. Dan
Yes, advancing cam timing "can", but not always be a benefit. I advanced the (stock) cam on one of my Studebaker engine's. Provided an additional cylinder 28psi. It can be a pain in the butt work though. YOU MUST have a good compression gauge on hand to complete this properly. NOTE - This or dyno testing is the ONLY...way to find out if advancing OR retarding the cam will gain horse power. Guessing will NOT give you anything but crap info ! Higher cranking compression will provide more power, when tuned correctly. Keep notes - 1. Remove all spark plugs. 2. Open the carburetor and block open. 3. Disconnect the coil wire. 4. Remove required parts to get to the cam drive. 5. Advance the cam 3°. 6. Plug the compression tester into the easiest plug hole to reach. Test the compression a couple of times 7. If the compression reading is higher, you did good. IF...the compression is the same or lower, continue . 8. If the above test shows a lower compression number, then "retard" the cam, 3°. 9. Repeat #7 above. 10. Set the cam to the highest compression number as noted with the tests above. Reassemble the engine as required. Mike
I've dabbled some, helped others. No guru, I know that there are guys out there with more money, time and knowledge than me. I can't beat them, but I can follow and build close enough to have my own fun. Dreaming of buying an obsolete Nascar engine for pennies you get reminded very quickly that your usage is not even close to it, let alone support systems, maintenance, and service life. https://www.facebook.com/eatmonraci...0ft-lbs-torque-13000-share-/1871092146237043/
Thanks Mike I’ll do what you suggest as I’m replacing the cam timing set before installing in its new home. I believe the smog year 318s have nylon teeth. Dan
That engine would be a kick, however its output is way beyond my skill level lol. My calculator says very low 9s in the 1/4. That’s about 2 seconds faster than anything I’ve ever owned and 4 seconds faster than any car I’ve owned. Dan
A lot of the stuff recommend for 1/4 mile racing doesn't work so well on the streets, and a lot of stuff that works really well on the street doesn't help the 1/4 mile racers. Decide where the car will spend most of its time, and build for that experience. In my experience, most used 318s have very loose timing chains & gears. Investing in a good set of double roller chain and gears, then degree in the cam (even a stock one) will probably help the power more then most any other performance improvements. 318s suffer from poor air flow with the small 2bbl carb and the restrictive single exhaust. A small 4bbl and dual exhaust can make a huge difference over the stock performance. The intake and carb mentioned above will be very helpful, as would the 3:55 rear gears, but that open rear may be a problem. With the open rear end, your performance improvement is going to turn into tire smoke, the heavier the car, the worst that will be. Traction assist (traction bars used to be cheap), even with a mild 318, helps a bunch, unless the goal is to make tire smoke. That 3:55 gear isn't going to help your gas mileage, especially on the highway, expect a 2-3 mpg drop because of the gear change alone (unless you have OD). Most of the other performance improvements will actually help you gas mileage, if you can keep your foot out of the carb secondaries. I did a lot of street racing back in my younger years. 318s in those "A" and "B" body cars properly done, put the hurt to a lot of much bigger motors. On the street, the "race track" is usually pretty short, its the same deal with fun to drive cars, the real life fun time is usually a pretty short "race track" and seldom sees an RPM range above 4,000 rpm. The trick was always applying the power available to move the car forward. If the car didn't move forward, you were just showing off.
@gene-koning so true. That dream engine doesn't start making power until 5K. Totally useless on the street. The thing that really drove it home for me was a certain Euro maker had throttle position sensors with a wiper. Just like a gas gauge, as it moved thru the range, it rubbed on a wire wrapped around an insulator. They tended to fail at the most used point. It was always about 10-15% throttle. Right where it was cruising around town or steady on the highway. That's where street engines live.
Thanks Gene, you’re another resident Mopar Guru, and I appreciate your input and knowledge, I have my eyes open for LSD unit for my rear end. I did a little Ok pretty big burn out with the donor car 83 Fifth Ave 2.70 or 2.90 gears? All smog equipment etc hooked up so in my little A Body I’m sure I’ll have to work on traction. Dan
Advancing a cam will always increase cranking compression pressure because the intake valve closes earlier, giving more cylinder fill at cranking speed. It will also increase low speed torque for the same reason, but at some point in the upper mid range the power will likely drop off earlier than it otherwise would. If I were doing this I'd degree the cam and find split overlap, then advance 4-6 degrees from that point. Just my opinion on getting a favorable result without spoiling the way the engine runs. As for 1/4 mile times, you probably won't see a big difference from this adjustment, but street manners will be nice and the engine should run crisply especially low/mid speeds.
One question, what year 318? The later 318s ran nylon timing gears which tended to come apart with a lot of miles. Most 318s with the exception of early LA motors carried a 8.5 to 1 CR. Good recipt for your 318 is find a pair of early J heads. Really good flowing head. Next, look for a good intake, best is the Edelbrock LD340. Good carb is the Carter 9636. Not produced anymore so you’ll have to find a good core and have it rebuilt. Exhaust would be next. Only breathable manifold that good is off the 340. Trouble is fitting them into an early A body. A good alternative is Doug’s headers. They make a header for the early A body. Next, is the cam. Good camshaft for that combo is the 1968 340 4 speed grind. It will really wake up that small-block. You can purchase a good grind from the many cam grinders out there. Oregon Cam is one. Inexpensive way to go. Of course you want to run a good electronic ignition Alas, your goal is to eventually dip into the low 14s, high 13s. This were it get tough. You are going to need a fairly low gear in the butt of that A body. I’m talking 3.55s to 3.91s. In order to do that you are looking at a rear end change. My bet you currently have a 7.25 rear in that car. Very limited in gear selection. So, you’ll need to begin your search for an 8.75. They are hard to come by and very spendy. Expect to pay around $1500 for a complete setup. Of course the 904 will have to be addressed. Consider a loose converter in the 2500 rpm stall range. in the meantime get the Dart driveable and safe. Address the brakes and all the other wear items. Take it to the track and work on your driving technique, launch, 60’ times etc. This is something you can be doing while modifying the car.
This is pretty much my plan. I have a Holley Street Dominator manifold with a Carter 500 cfm AFB, and a 8.8 Ford rear differential with 3.55:1 gears the engine is from an 83 Fifth avenue and I will replace the cam timing set before installation.I have a set of headers that I’ll modify to fit. My goal is to get the car to run in the 14s to start and then into the 13s hopefully. I won’t loose sleep if I don’t meet my acceleration goals but I think it will be fairly easy to achieve. Thanks Dan
Ryan, Your plan sounds like it should be a fun street ride. There is a line at which that 318 looses some of its nice driving street manors, I believe your build is going to get you pretty close to that line without going over it too far. I built a 318 that was backed with a 4 speed that had a pretty radical cam. The head ports were too small (318 size) so it ran out of air at just over 4,000 rpm, but man what a ride until then! Small head ports give better throttle response. The cam pulled from 2500 to 5500 (didn't see 55000 until after the 340 heads were installed), and it was a loping 1200 idle. Took some finesse to get it moving with 3:23 gears (would have been really hard without the 4 speed), but when the cam started pulling hang on, and power shift at 3500! The car was fun, really fast (up to 4,000 rpm), and broke a lot of parts, but is sure sucked trying to drive it daily. It was very temperamental, and the short but effective power band kept you on your toes all the time. If you were not paying attention you could get in real trouble, real fast. That car got 18 mpg @ 65 but less then 10 around town. It was a good thing I had a different car to drive to work.
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