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#1
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Imca hobby stock
Ok I'm new to imca and newer still to the hobby stocks. I'm trying to get this duster ready for next season. The rules are not very clear when it comes to a mopar so need some help. The car I have was hit hard in the rear and bent the frame by the kickup area so now the shackles are out of travel. On the chevies it says you can replace the rear frame from the "seam" with tubeing. well where is this seam and do you think I could get away with replacing the frame section on the duster from the kickup back? also exactly how much of the trunk/fender well can I remove? pictures would help a lot. Thanks.
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#2
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On a metric chevy it is right where the frame dips down on the back side of the rear end, so basically on a mopar it is by the shock mount crossmember. So make it out of the heaviest, thickest pice of 2x3 tube you can find
It also says If I remember correctly, that the frames must be connected from the front to the rear, so you can put whatever tubing in there you need, its up to you. |
#3
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Thanks Cage, I already have the subs connected with 2x3. I have to install pass side door bars as the cage now has the typical X in the pass side and the rules say 3 door bars on both sides. I'll cut out whats there and replace with 3 horizontal bars want to keep the right side as light as possible. also got to "plate the drivers side yet as there is none there.
While I'm here is there anyone that wants to get rid of a 360 kevco stock location pan and pickup. |
#4
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The rules say that you can remove the rear outer wheelwells to the seam where the 2 halves join. On our Duster, I took the whole trunk floor out and replaced it with 20 gauge sheet metal. I wanted to get rid of the spare tire well in the floor, and it was rusty anyway. Plus with the trunk floor out of the way, I could get inside the frame rails easier to reinforce the rear shackle mounts.
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#5
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Well I'm in the process of cliping the rear. gonna make some changes in hight were the rear shackles mount. need to get this car a little lower than it was. think I will flip the front mounts too.
Got the 360 tore down and found the thrust bearing had eat away the crank so need a new crank. While I was in there I messured the piston deck hieght. its 0.064" below with the sp405 pistons. comes out to around 8.1-1 comp with 72cc heads and 0.039" thick gaskets. I think I'll get some 0.025" gaskets but otherwise it goes back togather. So its a 360 with stock 1.88 valve "j" heads and a wieand X-cell intake and rochester 2bbl. cast exhaust manifolds. I can go either hyd or solid cam I have a .509 hyd that cam in a motor with the car but don't feel it will do very good with the low comp. any one suggest a off the shelf cam want lift to be under .525" so i dont have to do more to the heads. Gonna try and keep rpms under 6k so any ideas. I'm guessing the car will weigh 3000-3200 and we have to use 205 dot radials so don't think I need a ton of power. |
#6
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Off the Shelf Cam
We ran a Comp Magnum cam years ago in a Wissota Super Stock. It worked pretty well. With your compression something in the 280H to 292H might work out well. I would probably stick with the 280H to start with. I would hate to get too soft on the bottom end since with a 2bbl 360 that is all you have.
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#7
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Hum I have a ultradine solid I'll have to look but I think its in the 256@50 range with .575 lift (no lifters) would trade for a 284-.528 size cam
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#8
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i think comp cams under stands mopars better than most running a big solid in my super stock love it the 280h sounds perfict for your class i ran it years ago with a 484 mopar cam it worked will to sfr
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#9
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Camshaft Duration
The Magnum 280H has a duration of 230° @ 0.050" lift on the intake. I am pretty sure it is a single pattern cam. From what I remember we had it installed at like 106° or about 4° advance. This is from memory, but the 2bbl will not allow the full use of the 110° lobe separation angle. In that heavy of a car, I think I would stick with the 106°. This is .480" lift with a 1.5 rocker arm. It has a duration of 140° @ 0.200" lift.
If I were going with a custom camshaft I would look at something along these lines. Bullet master HC 275/3500 which gives you a duration of 231° @ 0.050" lift and a gross lift of 0.525". The lobe profile gives a duration of 149° @ 0.200" lift. This lobe is designed for the 0.904" lifter diameter of the Chrysler engine. Thus you can get a little more area under the lift curve with this setup. I would maybe look at the exhaust to see if you needed more duration or not. Typically in 2 bbl classes if you decrease the duration on the exhaust you can pick up torque. There is a limit, but it can be as much as an 8° difference in duration. You would have to go to a Ford or GM master on the exhaust to get the best profile at the 222-224° duration that I might expect to run if you have headers. Just some things to think about. |
#10
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Cast iron exhaust so it sounds like I should look for something in the 225-235@.05 range and no exhaust split. Are u saying that the install at 106*is helpfull to torque in a limited engine? So if i find a deal thats ground at 110* install at 106* it helps low end torque but gives up a little at the top? I have a set of stainless steel 1.6 rockers and the rules say steel roller rockers ok so I'll use them.
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#11
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Rear clip progress
Just a couple of pic's of the rear clip i'm working on
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#12
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A little more progress no garage so it fair weather only.
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#13
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Dooh! crap looks like I'll have to remount the fuel cell. I needs to be above the trunk floor.
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#14
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don't know what your rules are but I have two suggestions for you. 1 where the shackles bolt of for the leaf springs, weld a solid pad and use sliders instead of shackles, if you have to use shackles, have it bolt up vertically so you can put peices of metal between it to jack weight around. 2 get a factory trunk from a diplomat or equivilant car that has the spare tire mounted in the trunk floor, and weld that trunk in, that way you can mount the fuel cell down in where the tire mounts. It will keep the cell lower and it still fits the rules by being mounted above the trunk floor.
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#15
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Can't use sliders or lowering blocks. I was going to Mount them as you said but am trying to get car lower without being to ovious so ended up mounting them simular to stock but the frame rails are about 2" higher where the shackles mount. I put a 18ga sheet for a trunk and built some cell mounts over that. I'm just keeping as much weight on the left as I can and did build in a little wedge. After the first few races the track dries out a lot so left heavy should work good for me. Hope to borrow a setof scales when its done to determine a good starting setup.
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#16
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I put the fuel cell so high the trunk barely closes. Making the rear of the spring adjustable changes to many things.
And why would you build wedge into a car? I run dirt. |
#17
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Dry slick track?
When my track goes dry slick the less left rear the better. I am at 40lbs LR now and I am gonna even it out. This is a pure stock. We just don't have the motor other classes have so we can't power through the turn and force the car to turn. I wish now I had evened out the rear springs instead of putting a heaver on the LR.
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#18
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I have always ran the same springs too.
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#19
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Ok well you have to remember that most of my racing experiance was in a 3-link modified. One of the things I used to do to get some bite off was add some weight low on the left side. I just figured with the 205 dot tire that traction would be the determining factor not power. More concerned with getting this thing to turn than the power output. If I can get it to handle then I can work on more power latter.
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#20
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So I was trying to figure out what shocks to use and the closest I could come is the camaro-fronts and the gm metric rear. Is that what everyone uses?
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#21
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We just use the set of Bilstiens that come in the set of 7. Pretty sure they were designed for Metrics, and bolt up just fine once you take the GM crossbar out.
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#22
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Thanks I'll keep my eyes open for some used ones. I'm a cheep sob.LOL
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#23
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weight % A body help needed
A body hobby stock, dry slick rough .4 mile track. What ideal front/rear and side to side percentages should I shoot for. I can move some things around if I have a goal # to work with. Thank you for your time. RR
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#24
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I think that moparracer and cageman would be the ones to ask as I am just getting into the hobby class. My first guess would be 51% cross 52+ left and as much rear as you can get up to 56%
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#25
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You arent ever gonna hit 56% rear without ballast, which isnt allowed in Hobby Stock. I worked my butt off last year building our Demon, and we finally got it up to 50%. Cross weight is more of a driver comfort thing in my opnion. Damon likes his car a little on the tight side, so we run it about 52-52.5%. That way he can attack the corners harder, and have very little chance of losing the ass end. In hobbies, spinning out is sure disaster.
Rob....you gonna get that thing on the track this year? |
#26
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getting a little closer. Got the cell mounted and the rear bumper mounted. also got the radiator mounts started .Got a plate on the drivers door. So now have to redo the pass door bars and do a lot of tin work.
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#27
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Just a suggestion to keep the IMCA tech guys off your butt: hopefully you can put the tail lite panel back in, or replcae with another one if yours is gone. They really hate it when that stuff has been cut off!
Lookin' good! |
#28
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Yea I have it. the hard part is going to be matching it up to a 73 charger quarter panel. The sheet metal on this car is so beat that I'm going to try and replace it with the charger tin at least from the top of the doors down.
I think I saw on yours that you removed all the inner structure bellow the quarter windows. I'm going to wait on that untill I see what the GM guys are getting away with. |
#29
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would you use this cam in a 9-1 hobby motor if you already had it?NF .904 Flat Tappet Profiles VL = .016" w/1.5:1 Adv = .020"
adv dur 0.050" 0.200" lobe lift 104 106 108 110 NF62 270 243 162 0.3651 0.113 0.105 0.098 0.090 NF61 274 247 164 0.3727 0.117 0.110 0.102 0.095 Its a older ultra dyne grind I think its ground at 106 |
#30
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Yes, cut out the 1/4's all the way back to the wheelwells.
If I understand the specs right, you'll get about a .547" lift with 1.5 rockers, correct? Looks to me like a pretty decent cam. |
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