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Small Block A/LA/Magnum Performance

Discussion in 'Performance' started by TWX, May 21, 2008.

  1. Jerry18

    Jerry18 Guest

    I am almost finished building an LA 360 that will go in a 73 Plymouth Duster Automatic. Here's the story so far... The duster is an original slant six, bought for a fairly decent price. I went searching for an engine for it and found a 76 Dodge 1 Ton Van with the 360. We pulled it out, Rebuilt it, had it bored .30 over, decked, chamfered, honed, the whole nine yards.
    We had the piston rods resized, and shaved .10 off of the crank.
  2. lazyflash

    lazyflash Member

    Apr 7, 2007
  3. My brother and I bought our 72 Dart swinger from our neighbor. He built the stock 318 several years ago. He went .10 over, new seals and bearings, eagle crank, h-beam rods with KB Hyper, zero decked to keep the compression down around 10.5 to 1, balanced and blueprinted. He had the recipt for the bottom end work $5,500! He installed a Torker 2 intake, 7177 cam, double roller timing chain, Hooker comp long tube headers(over 8 hours to install), 2 1/4 dual exhaust, 120 gph fuel pump, and the orange box from mopar with stock dist. and coil. He had a 625 carter AFB and two 10 inch air cleaners stacked. He took a set of 360 heads and had them ported and polished and changed to 2.02 intake with new h.d. springs and stainless valves. It has a 727 with shift kit and a 9 1/4 rear with 4.10 posi. 14 inch cragar ss and BFG's It didnt run very well since it had been sitting for a couple of years......a couple of navy guys looked at it to buy and passed since it looked pretty rough..... We got to talking to him about the car and told him we were interesed in buying it....a couple months went by and he told us if we could come up with $2000 we could have it!!! We gave him the cash on the spot, he tried to get it running and it kept locking up the back brakes. We brought it home on our car trailer and went to work on it. It turned out when he cut the e brake cable putting in the 727 he vise gripped the cable up under the car and the e brake was to tight and dragging! We took off the rusty vise grips and fixed the e brake cable and the car drove fine. He then brought over the boxes of parts for the car. He has triples of all the exterior trim parts. We got 2 complete trim sets for the windshield and back window, 6 sets of dart and swinger badges, filters, new carpet kit, new headliner kit etc.... The interior is in perfect shape already! The carb was toast! We put on a new 750 carb and 1 inch spacer, MSD 6al with pro billit distributer and blaster 2 coil. We also installed a B&M ratchet shifter. The car came alive! It runs great! Turns out due to the brake problem he put less than 1000 miles on the new motor. I was ready for a 440 stroker for the car but now we will wait and play with this setup first. I really like the fast revs this motor puts out. I have friends with built motors and none rev like this one. It has a top speed of like 115 but man is it quick. I have not done an official 1/4 mile but our crude results had it around 13 seconds at 105 with a 2 sec 60 ft time. I should be getting my g-tech pro for more accurate times. I plan on running at the strip next year just to see. I have been messing with the timing and carb and have it running really well. It loves to rev! It runs right past 6000 rpm! I have to shift when I see it get to around 5,000-5,500 to get around a 6,250 shift or I will hit the rev limiter. I know my low gearing has alot to do with it. I am getting some bigger tires to help out. I might even go to 3.73 gears so I can run on the freeway at 65-70. I just wish there were more places to run your car around here. Thanks and Go Mopar!!!
  4. Valiantman

    Valiantman Guest

    Tried and trued combo making a dynoed 415rwhp (about 525-530 flywheel hp).

    360 ('73 block)
    4.030" Diamond forged flat-top pistons (total 10.25:1 comp)
    6.123" forged H-beam rods
    4" forged Eagle crank (408ci)
    Crane retro-hydraulic roller cam (230/236 @ .050" and .528"/.548" lift), lifters and 1.5 gold rockers
    Edelbrock RPM alloy heads, mildly ported, bowled and re-seated out of the box (2.02"/1.60" valves)
    M1 single-plane manifold
    800cfm Barry Grant annular carb
    MSD billet dizzy
    Crane Hi-6 ignition, leads and PS92 coil
    Viscous clutch fan
    1 5/8" shorty headers (custom headers to follow)

    With a bit more head work and decent set of headers, this combo would probably make close to 550hp - probably more with a bigger cam. Peak power is from 5750-6250rpm (but will rev to 6800rpm), and the torque curve is very flat from about 4000rpm to 5250rpm.
  5. StrokerScamp

    StrokerScamp New Member

    May 4, 2010
    You wanna know what we've worked on before? Well, I've turned wrenches since 1974, so I won't bore you with a list. I've been ASE Certified since I was nineteen (almost 30 years ago) and ASE Master Certified since I was 21. Although I'm retired due to a disability from a practical joke (DON'T fool around in the shop, boys), I still keep all my certifications current. Also a certified welder since I was 18. I am still certified through the big three plus Toyota and Benz. I've had over 200 vehicles since I was 14. Most were hot rods of some sort and most were Chevys......"cough, hack" because as a single young punk, that's all I could afford. I have owned several Mopars through the years including a 1971 440 R/T Charger, a 1973 340 Rally Charger a 1971 Dart, 1967 Dart, and various other A bodies. Several military Power Wagons come to mind as well. I really like these stroker motors. I've built 2 408s and a 416. My current project is a 408 Scamp. I've not really "invented" anything so to speak, but I've repaired and built a boatloat of stuff through the years. I detest the new Magnum engines (sorry) because I think Mopar walked bassackwards when they knocked off the shaft mounted rockers. Yeah, I'm old and old school. I think the LA motors had it all over the Magnums. Not trying to cause a war.....just my personal opinion. I've seen flow numbers for both heads on a flow bench and the Magnums ain't impressed me like a good set of J heads. I know folks run um with great success...but they can keep right on. I'm also a big torqueflite fan. I reckon you could say I sorta have my own way of building those. There are a couple of mods most shift and reprogramming kits leave off that I do that helps firm up shifts and keep the clutch packs tight. ....and I love the 904. Built right, they'll hold over 1000 HP. Anybody says different, they need to come to Georgia and I'll show you. Or better yet, ask Bucky Hess what he ran for years behind the HEMI in his Super Stock Cuda. Yup. A 904. I'm toying with the A500 idea for this latest project, though. Not sure. I already have a 904, so.......
  6. dartndodge

    dartndodge Well-Known Member

    Jun 9, 2004
    This thread has dried up somewhat, so here's my little budget build from 1985, when I was young and had more hair.
    .030" over, cast pistons.
    stock rods, crank etc.
    Heavily ported J heads, 2.08 (too much) 1.60s.
    Racer Brown solid ST21....520" @ 286o, 273 rockers.
    Offy Equaflow 360o manifold (rubbish but cheap).
    780 Vac sec Holley.
    Headers with 2 1/2" full exhaust w crossover.
    DC electronic wth chrome box.
    68 Valiant 4 door street car, 4.10. 8 3/4" sure grip.
    Pump Gas, Full exhaust, std 360 2 bbl converter!!!!, retread Goodrich pattern 245/60/14s street tyres (non sticky).
    12.10 @ 111 mph best time.
    Unbalanced engine, Unexotic, Std MoPower.
    Never beaten on the street by a Chev or Ford!!!. Remember Full exhaust, Chebbys could never run with the exhaust hooked up. Pretenders use to take the first side street or look the other way, when I pulled up next to them at the lights, the Car had a rep for a year or so. Note: Yes there were kwika cars at the track, usually the trailer queens.
    Mopar....Gotta love it!!
  7. biggobs64

    biggobs64 New Member

    Mar 24, 2009
    couldnt u just sleeve te block?
  8. so here it is. I've spent a lot of time trying to figure out just about how much HP my 318 might have now.
    everyone every where either wants to build a 318 for cheap and everyone says "just go to a 340 or bigger" or any build i've seen like in magazines they just build a budget or cheap 318 and are impressed it got over 400hp. i spent a lot of time "just under a year building my 318." and about $4000 in parts except for machine work on the block was $270 and $200 to have my heads machined and put together so my valve springs were right on the money for my cam. It is in my 99 dakota in front of a 727. have only got run it for about 2 hrs so far. its a mud truck and with all ive done and spent im not going to mess around with driving it till its done, next im putting in ram axles and ill be about finished. but the longer this project goes on the more excited i am to see what my engine can do. its seems like everyone has thought about this engine but i did it. i tell dakota owners it what you wish your could be. so enough blah blah blah. here is what i did. starting with my short block mathematically and i'm talking lots of math and research. my stock crank and rods with .060 over sealed power pistons and chromemoly rings and .040 taken off the deck creates what i believe to be almost an 8000 rpm stable short block. i have a set of magnum heads witch anyone who really knows are amazingly efficient and i spent about 40 hrs in my garage polishing and opening the ports. then i had 3 angles cut on my valves and had the hardest exhaust seats available pressed in, then i had another .020 taken off the heads which have been milled before probably .010 it was before i got the engine and had new springs keepers ect and set so i can run my cam with out a fear of float or too much spring with can take away too. next i installed my comp cams xtream energy cam with a .480 lift and roller lifters "obviously" its a roller engine. and 1.6 ratio roller rockers bringing my total to a .512 lift. which i found to be almost exactly where a flow test on my head starts to plain off. with what i took off the heads i believe my combustion chambers to be 59 to 58 cc its gotta be close. my figures put all that at really close to 10.5:1 not bad considering stock is 8.5:1 and with my dual plane high rise intake and edelbrock 750 and headers it should be able as efficiently as possible breath. remember its a magnum out of a 95 but its also a mud truck so electronics = bad. hence the carb and next an accel points distributor and a 47,000 volt coil. not performance related but it really cranks with a 1300 cca battery and a 1 gauge welding wire connected to the new starter. it all show attention to detail and that every where i can i have added all the over kill i can for the sake of making this dakota the one you wish your was. i have more info i've learned maybe too much so fire away. its my first engine build but its been done right im sure. just thought id like to let every one know a 318 or as i call it now 327 has been built and the math says its as efficient and strong and stable as a engine with its bore can be. it also has 35's and about 14 inch of lift. ill add pics later and more info as needed i just wanted to see what the mopar world thought
  9. dana44

    Ad-Free Member

    Jun 17, 2002
    You have done your math, and I do have a couple comments. Sounds like you did a bunch of work on the heads, which is where I say all the power really made, given the compression and cam specs you have. did you remove the lip inside the combustion chamber where the transition from the combustion chamber and the quench pad area is? I suspect you didn't which is why there is no gain above the lift you have on the cam, but that's OK, I think you did pretty good as is on that. Did you also remove the raised ridge at the intake port prior to the short side turn before the intake valve? Talk about a power killer, Rocker arms. Did you go with adjustable rockers or are they stockers? I know stock is 1.5 ratio, but 1.6 is available stock for the newer Magnums, too, with that much lift and duration, roller or not, I myself really like to ensure that lifter isn't being pressurized so lifter pump up isn't allowed to float the valve any amount whatsoever. The rest of the engine sounds good, high volume oil pump I assume, extra chamforing of the crank oil holes helps, but remember, if you have a nodular iron crank and not a forged steel crank, 7000rpm is all you are going to want to turn her so the crank survives metallurgically the bearings and the crank material due to the speed and natural friction no matter how much oil you have will cause bearings to start galling, just a fact of life with a cast (nodular) crank, especially if she would be at above 7000rpm for several seconds at a time (say, three to four, but ten is a death sentence). Mathematically you are correct, but physically you wouldn't be, just a caution.

    What are you using for stall converter for this mudder? I am kind of partial to something in a 2200-2500rpm range, anything more doesn't seem to make much difference, even for mudding, it takes you right to the beginning of the torque and hp band, why waste power being in the middle of it with a higher stall?
  10. well i did a little work on the lip in the combustion chamber but basically just enough to smoothen the transition i wanted to keep as much material in the combustion chamber as possible so they didn't grow or vary. the intake ports had a sort of ridge or rise right at the frond so the so the intake ports sorta had a hill that narrowed them. but lucky for me it was in the casting where there is more than enough room to grind it out and i'st on the low side of the port tward the head and not near the water jacket. i know lots of these heads have problem with cracks but the ones that are good are good and i had them re magnafluxed after the porting just to be sure before i put em together. the rocker set i got came with new studs so the rockers are individually adjustable and they are 1.6 roller rockers if i didnt mention that. i took out stamped 1.5 rockers and the rocker set had better push rods that were a touch shorter than stock. i dont ever plan to run the rpms that high, just with my center height of my pistons are quite a bit better than a figure i seen for minimum center height desired to avoid piston slap 1.755 thats just luck but "best rod length to stroke" 1.75 nascar runs and mine is 1.85 which produces a little more torque at the lose of some rpms but i wont touch that and the ratio of bore to stroke should allow for 3864 ft/min piston speed i believe anyway i dont intend it to be fast for a minuet it should be more than durable. and yes i did get a high volume oil pump and all new bearing and gaskets with my rebuild kit and everything plasti gauged nice. my rpm range on my cam is suppose to plain off at 5500 rpms anyway its just good to know its not pushing the limits for the block. i bought a cam i wanna use it all lol for now i just have the stock converter the trans it out of a 94 ram like you said i dont wanna be half way through my cam and its a light "er" truck. and i plan to be in low traction situations so slipping mine isnt a huge issue and i can get engaged and moving with plenty or torque and have the power to rapidly gain wheel speed if i need to clean the tread out. plenty of fore sight is going into durability. but i do plan to put in a rebuild kit and shift kit cause the are cheap and i wanna do it all in one shot and its fine for now. one day my curiosity got the best of me when i was moving it out of the garage it was in 4 wheel drive and i gave it about 3/4 throttle and on my dirt road it had no trouble spinning all 4 35's for about 20 feet. its hear say coming from me technically, but a friend of mine who helped a little in the build says his drag car is a little over 1000 hp and and at the local drag strip he has the smallest engine a 340 but when he pulls up for his first run they say "here is the fastest car thats ever run here. hahaha i love telling people about that
  11. not that its hardly worth a post after another but i also took off the mechanical fan and ac pump and i have 2 electric fans one in front and one behind the radiator and yes i did remember to wire them so they blow the same way lol also i forgot to mention earlier i from what i gather since i can't dyno it at least not quite yet . but i used to think it was about 450 hp but with every thing ive seen about all the budget builds and the extra work and $$ is it un reasonable to think i might be at 500hp. one i seen used basicly various junk yard parts and was around 415 or so. i didn't build it with any peak goal in mind i want a engine thats ridiculous about its power to weight ratio and still strong enough to last and the 318 is over looked for its durability by everyone who has never took one out and and just beat the Heck out of it for years and sold it still running. and as far as im concerned the it doesnt have much less potential that a 360 but it does have a stronger crank and the smaller main bore leaves more meat and structure for block integrity also it has unless im remembering wrong the same size main bore as a 350 or 400 sb. ..."pause"...just checked 350's have a 2.30 to 2.45 and the 318 is 2.50 and the 318 is a cast steel crank not iron like the 350 and 360. so i have extra block to hold my crank shaft.
  12. triple j

    triple j Guest

    No you are not, the 318 has a bore size of 3.91,smaller than the 360 mopar and 350 chev of 4 inch. Right also that there is no OE crank for 360 mopar in forged. Good luck with this monster!

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