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Small Block A/LA/Magnum Performance

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

  1. TWX

    TWX DO NOT FEED THE TROLLS!
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    Okay, since we've had decent interest in the Performance subforum I figured I'd add a few pinned threads.

    Please post what you've worked on, participated with, or designed (if it's been implemented) and what kind of results it gave you. This will give others an idea of what to look at. Be as specific as you'd like. Everything from going to lighter aluminum parts to a Magnum top-end swap with forged internals and an R3 block is welcome.

    Also, please keep it to only your own work and experiences, rather than hypothetical or hearsay, so that we can establish actual results...
     
  2. TWX

    TWX DO NOT FEED THE TROLLS!
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    So, I'll start off. I went through a series of changes to what had started out as a factory '78 360 2bbl. I found that the cam made the biggest difference, though the carburetor and intake manifold as a change, and the headers as a change also had a fairly dramatic effect on a 140,000 mile engine.

    I ended up, before it came out to build the stroker (needed some of the parts) as a 4bbl 360 with about 8.5:1 (stock) compression, with an Edelbrock Performer aluminum intake, double-roller timing chain, Comp Cams Xtreme Energy 262H camshaft and lifter set, Edelbrock clone of a 600CFM Carter AFB, and TTI step headers. The go-factor was great. I probably should have gone with the 750CFM carb though, as the 600 felt like it was holding back a little. Additionally, I had a mild lope with that cam, even though it's not exactly a thumper.

    It came out now that I'm finishing up my stroker motor, but it definitely had some more go. Just 150,000 miles was too much on the bottom end for the amount of power I wanted and with all of the bad seals, it just wasn't worth keeping it as-is.
     
  3. Rodger

    Rodger Member

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    Hola Sir

    With a 1975 AMC 304 I swapped the 304 heads with a pair of late AMC 390/ Early 401 or 360 Heads that were with the dog leg exhaust ports. The heads were lightly attacked by a lil grinder on all places that were pointy, sharp or the like.

    The 1975 304 2 bbl spec'd cam was re-placed for an then spec'd RV/Torque Cam from Crower in San Diego ( I'm from Poway ).

    The OEM 304 2 bbl was also swapped for the 401/390/360 intake manifold. The 4 bbl carb was a OEM unit direct from a early era H-O ford 302 ( my brother Phillip's mustang ).

    The Air Cleaner Housing was the Matordor/Ambassodor Dual Snorkle Unit from a 401 engine ( I then took off the 4 bbl 401 sticker and replaced it with an 2 bbl 304 sticker).

    The Hornet's ( or Gremlin's ) with an OEM V8 all had the passenger exhaust manifold "of the log design" from an earlier AMC usage due to possible shake/movement of the engine to the chassis. The "notch" was made and exhaust manifolds with the better design of all other engines that had no drillings for the smog tubes where used.

    The car was then made with exhaust pipes and muffler's of the exhaust manifold diam to the rear on both sides with an "H" pipe.

    The tires were of the factory size of an Fast-Back Hornet "X". The rear axle was the stock ratio with both sides pulling. The LT Duty Torque-Flight went out at about 44,000 miles.

    As this, the car would do 106 - 104 MPH in 1320 feet ( just two gears ) at Temple-Academy in Central Texas or 143 MPH on top end in Germany ( I never did like the idea of having a non OEM cam and purchaced a 1976 360 Police and etc AMC Cam while in Germany ).

    I had the non-Power Steering A/C equipt'd car from Nov 1974 until May 1981. From Sept 1972 to Nov 1974 I had an like Gremlin "X". The following car from 6 June 1981 to the summer of 1991 was an American Spec'd Rabbit "S" with "goodies".

    Before the 1973 Gremlin "X" I drove an 1967 LA 318 powered Plymouth Belv II 2 dr.

    Since 1998 I have gone back to an 1967 440 powered Chrysler 300, and several othe MoPar's that I have enhanced the same as above.

    Rodger & Gabby
    COS
     
  4. 73_duster

    73_duster Guest

    I am almost finished building an LA 360 that will go in a 73 Plymouth Duster Automatic.
    Heres the story so far... The duster is an origninal slant six, bought for a fairly decent price. (Stock except for Weld Draglite Racing wheels, And I am putting in bucket seats from a 74 roadrunner.)
    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.

    We went with a mild cam .454/.454 218/218 Comp Cam (will be change to about .550 in a year or two)
    I went with a smaller cam because I didn't want to spend $350 on adjustable rocker arms (i'll worry about it later).
    9.3 compression pistons (coated with material for less friction)
    Added Steel timing gears and a true double roller timing chain.
    Edelbrock Performer Air Gap Intake Manifold Port matched to heads.
    Original 340 "J" Cylinder Heads fully ported by Todd Mickenly. (Outstanding flow)
    Holley remanufactured 670 CFM Street Avenger 4bbl carb.
    Headman small tubed street headers, leading directly to dual 40 series flowmaster mufflers. (no piping yet due to cost).
    MSD 6 series with a Blaster 3 coil.
    SplitFire Platinum Sparkplugs
    Plus all the small stuff was replaced, Oil pump, Ect.
    Mopar Black valve covers with matching Air cleaner.
    The block was painted yellow, headers are black, heads are aluminum (paint), aluminum intake, chrome oil pan, black water pump, black and yellow pulley, basically everything is a bumble bee theme.

    It has 3.55 Axle ratio (not Posi)
    727 tranny with reverse shift kit being ordered.

    And as far as the van goes, it turned out giving us a free engine...
    Van was $800 and came with a 4.11 gear posi-track dana 64 Axle!
    We sold the Axle for $480 and took the van to a metal crusher and got $510 for it. Gaining us a few extra bucks.

    Being busy with business, it may take up to a few more weeks to a month before the engine is in the duster.
    When it gets broken in and has some miles on it, Ill post how it runs on the 1/4 mile and the dyno specs.

    Jon.
     
  5. rockhq

    rockhq Member

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    I built a 323" smallblock, first with stock heads then with 273 (closed chamber and slightly ported) and now i'm contemplating between a 365 and a 408 small block, i've got all of the top end stuff ready to go including ported edelbrock heads that should support +500 horsepower. building a killer shortblock is not a question for me, just the displacement and whether or not to use turbos or forced induction.
     
  6. rockhq

    rockhq Member

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    Also i just got my std 360 block (28.03.1973) back from ultrasonic testing where they found that only one spot was less than 0.200 thick, so i'm going to fill the block up to the core plug holes. I willl defiately keep you in tact with my project as soon as it gets updated
     
  7. uglyvaliant

    uglyvaliant Member

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    Two approaches, both very economical-

    First the basic hot-rod approach:
    Car is a 1968 Coronet, 904 auto, 2.76 hwy gears.
    Engine: 180,000 mile stock 318.
    Recipe:
    Basically left the short-block and heads alone. Went with an eddy 600, wieand dual plane intake, Summit "small" cam (204/212 @ .050, .420/.444 lift, 112 LSA). El cheepo Hedman headers with 1 5/8th diameter. Electronic ignition conversion, 16 deg initial, 38 total @ 2500rpm. Everything else, valvesprings included, were left alone.

    Results? 15.2 @ 92mph in the 1/4, shocking considering the mild nature of the engine, total mileage, hwy gears, and size of the car. A side benefit is that it averages low 20's on long trips provided I keep the speeds below 70mph.

    A little more involved, but basic and economical approach nonetheless-

    Car: 1976 Plymouth Valiant, bone-stock 318, 4 speed O/D trans, 2.94 gears. Took off tailpipe and dumped the exhaust before the wheel, no muffler. 1/4 time in this state was 16.7 @ 79mph.

    Recipe:
    Basic 360 short-block. 0.060 overbore. Stock replacement cast pistons, pre-fitted cast-iron rings. 8.2:1 CR. Basic bearins and balance at the machine shop. Stock rods/bolts.
    Heads were basic, non-smog 1976 heads. Basic three-angle valve job with stock 1.88 intake valves by a good shop.
    Cam was MP "268/272" cam, basically 228/232 @ .050 (although it didn't act like it was that big, seemed like a typical "218 @ .050 cam), .450/.455 lift, 110 LSA.
    Eddy Performer intake.
    Holley 600cfm single feed carb.
    Hedman headers.
    MP electronic ignition, 18 degrees initial, 42 total (high, I know...but that's where it ran best), all in by 2400rpm.

    Engine had great torque and idle characteristics. Did great paired with the 2.94 and wide gear spacing of the 4 speed OD trans. Ran a best of 14.2 @ 94 mph (understand that the STEEP drop off into third depressed trap speeds). If driven very conservatively @ 55-60mph, would average over 25mpg with the extremely tall final gear ratio of 2.14:1

    Swapped to 3.90's and got it down to 13.7's. Enough low end to get sub 2.0 60ft times.

    Later version of the 360, same car:

    360/stock resized rods/ARP bolts/KB107 pistons ~ 10.5:1 w/ milled heads.
    Heads extensively ported professionally to bring intake flow up to 260cfm, exhaust lagged at 175 cfm (only a 5-10cfm improvement...too aggressive on the short side), milled 0.060 to get combustion chambers to ~60cc each.
    Hughes 232/238 @ .050, .520/.544 lift, 110 LSA cam paired with Rhoads lifters (got 13 inches of vacuum).
    Eddy performer "rpm" intake.
    Holley 750 DP.
    Good ol' Hedman Headers, 1 5/8th (although I'd have like 1 3/4 or stepped headers).
    MP electronic ignition w/ chrome box. 12 degrees initial, 36 total, all in by 2400 rpm.

    In the valiant w/ 3.90's still, but now with a non-OD 4 speed manual trans. Best ET 12.6 @ 106mph. Fuel mileage: Horrid. Driveability, not bad, good vacuum and wide power band, pulled strong to 6500rpm.
     
  8. Pancho1

    Pancho1 Guest

    thought I'd post my build, was not after high rpm's or HP just wanted to wake up my little 318 a bit 1978 Plymouth Fury Sport. It was always a bit annoying having to build up speed to pass someone or else waiting till you reach a passing lane.

    stroked to 390. eagle forged crank eagle I beam rods 6.123 floating.
    KB 4" stroker pistons, step dish .030 o/s.
    balanced assembly.

    Original 318 heads with 1.88 inlets left the exh valves original.
    port matched inlets, polished exh, tuliped bowls and reamed out the runners.

    Lunati voodoo 60401 cam.
    213 in 221 ex @ .050
    112 lobe sep.
    .484 in .506 exh with 1.6 roller rockers
    4120249 springs.

    Weiand Action + manifold, Holley 600 carb.

    Replaced that with MP 6 pack manifold topped with Demon 6 shooter carbs progressive linkage

    260HP 436 ft lbs [at]2000rpm.

    15.1 ltrs / 100km on 500km trip.

    Have just bought an old 360 engine and will be putting in 2.02 inlets port and polish.
    will replace cam with Lunati, 227 in 233 exh. @ .050.
    527 in 547 ex.

    Have a set of headers to fit as well.

    will post dyno readings once this is done.
     
  9. New here and just reading through, why fill the bottom of the block? What would you be using to fill it up?
    I have only heard of drag racers filling their blocks up with an epoxy that went hard for more ridgedity, but an engine for more general use I haven't heard of before and only at the bottom where the stress is the least!
    Can someone enlighten me please.
     
  10. TWX

    TWX DO NOT FEED THE TROLLS!
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    If it's too thin (as he pointed out) it would run hot and possibly have a weak point there. Filling it where it's weak would increase the life of the engine block.
     
  11. sbknut

    sbknut New Member

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    Doing it as cheep as possible ! I started with a 1972 truck 318 block and crank. The odometer showed 73k so the block was in good shape. Used Polyhead rods and wrist pins. 1968 pistons with 4 valve reliefs. MOPAR performance rings. Comp cam and solid lifters, 236' @ .50 .474" lift. 1966 273 heads with stiffer springs, stock valves with 3 angle valve grind. Wiend accelerator manifold. Holly 650 double pumper. Mallory dual point distributer. This is in a drag race prepared 1972 dart, weight 3025 lbs with driver. Best ET 12.85 @ 104.86 mph. Shift @ 6700 rpm, and hang on.
     
  12. Mr.LH

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    Wait a minute, so you CAN put Poly heads on a modern small block!??!

    what did you have to do to make it work?

     
  13. sbknut

    sbknut New Member

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    I'm still working on that one! From the flow tests I've seen there would be not much advantage to using that combination. The polyhead exhaust port is very restricted, and the lack of a good intake dosen't help. I did use the connecting rods and wrist pins, as they are much lighter than the stock '72 318 units.
     
  14. Mr.LH

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    Awesome. Take some pics!

     
  15. sbknut

    sbknut New Member

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    I'm not much for taking pictures. Look at scta-bni.org 2008 pictures page 6. The unidentified 72 dodge crew cab is mine. It has a 258 cu in small block that pulled the truck to 126 mph. It is a destroked 273 that puts out about 325 hp at 6500. The innards are "secret stuff", the carb that was used on the record run was a 1050 dominator. So much for carb sizing formulas. This little motor pulled the truck to a 15.16 and 92 mph in the 1/4. Look at the specs for mid 60's 383 chargers and 400 more or less brand x cars, then reconsider building a 273/318 mopar.
     
  16. TWX

    TWX DO NOT FEED THE TROLLS!
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    Interesting use of a crew cab...

    I just bought one yesterday. How did you lower your suspension in front down, new springs, drop spindles, or something else?
     
  17. sbknut

    sbknut New Member

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    OOPS! It doesn't have to corner or ride smoothe. The coils were cut A BUNCH. There is only about 1/4 inch of travel till it bottoms, bump stops were removed. The front tires are only 24.5 in tall. Not exactly a street combination. Do you need any door glass?
     
  18. TWX

    TWX DO NOT FEED THE TROLLS!
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    Well, from a perspective of scarcity, I would gladly look into obtaining more of the glass and the like that's in the rear doors, and come to think of it, any other parts that are unique to the crew cab that you've stripped off...

    What size wheels are those? I test-fitted a 15" wheel tonight and it seemed to fit, but it's a trailer wheel so it's almost all negative offset. I'm almost more interested in using 15" wheels based on what I intend to do with the truck if they'll fit, but it would be unfortunate to find out the hard way that they don't fit. If yours are 15" with stock rotors then I'd assume that your calipers are at least as large as stock ones, and that would mean that I could reasonably expect to put 15" wheels on mine too.
     
  19. sbknut

    sbknut New Member

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    American Racing (summit) 16" x 6". This truck has drum brakes.
     
  20. Bearhawke

    Bearhawke Things happen for a reason

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    ca. 1994 I took a 1974 Dodge B200 van with a 318 bottom end, 360 head and dual exhaust that had terrible driveability with the nasty Holley/Mopar 2 barrel carb.

    I bolted on a stock cast iron '360-4V' manifold with a 1972 Chevy Quadrajet carb...............van ran 1,000% better and delivered 3 more MPG based on memory here.
     

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