Hooking up an A Body Mopar
My bracket car needs help, but I'm not sure which way to go with rear suspension mods, and since the Stock Eliminator '67-76 A bodies with small blocks are very similar to what I run, power-wise, I thought I'd ask for some advice on making this thing hook.
Here's the car's specs: 904 Torqueflite-equipped 1972 Plymouth Valiant 4-door (just 14 pounds heavier than a '72 Duster, so should be very similar chassis dynamics; same 108" wheelbase, etc.) Race weight with heavy-*** driver 3,600. Engine is a near-stock, Vortech supercharged 360 Magnum running 10 pounds of boost; chassis dyno says 445 RWHP at about 5,500 rpm and and 470 RW torque. Redline is 6,000 for reasons of longivity. Best 1,000-ft. e.t. was 9.74 @106 mph. Best 1.8th-mile (same pass) was 7.59 @94. Those were with minimal bite (1.81 60-ft. time) No quarter-mile times available, but that equates to approximately 11.85 and 116mph, 1/4-mile. The rear is an 8.75" Auburn Sure Grip, (new.), and the ring and pinion I have for it is a 4.10 ratio (will be installed, soon.) The times I gave you were done with a 3.55.1. The 4.10 will go in as soon as the Moser axles get here. No spool, just a NEW limited-sliip. New slicks will be probably 28" tall. That will put me at the finish line of the 1,000-foot strip I run, just under the redline with the 4.10 gear. The tires I had when I ran it with the 3.55 were 26"-tall, B.F. Goodrich T/A Drag Radials. No burnout. No traction, either. It spun all the way through 1st gear, no matter what, but it was only 48 degrees... so, maybe that was why the VHT didn't seem to work. Anyway, the 1.81 60-foot times I turned won't get it. Wheelspin is my enemy, so I need some advice as to which way to go with the mods. What I have in use, currently insofar as "traction aids" are: stock, 5-leaf rear springs with three clamps each side, on the front section; pre-load air bag on right rear; adjustable pinion snubber, 1/2" gap; 90-10 shocks up front with stock torsion bars. KYB Gas-Filled shocks in back, non-adjustable. 8" wide BFG T/A drag radials at 16-pounds, on 7"-wide, 15"-diameter Centerlines. Spin city... I know the tires have to go, and I am not averse to buying REAL drag slicks from Hoosier, or M/T... or, whoever, but this car has very limited lateral wheel-well dimensions (not like a Duster, which has more room), so they can't be 10.5's... those would hit everywhere, I'm afraid. They DO need to be 15"-wheel size and 28"-tall... no exception, because of the wheels I have and the gears I'll be running. Other than that, manufacturer and width can be anything, within the "fit" parameters, width-wise. What I REALLY need to know is this: Is it possible to get this car to hook WELL, with "old-technology" super stock springs, or do I really need to bite the bullet and buy a set of Cal-Tracs or Slide-a-Link bars? This engine pulls really hard at low rpm's and will generate some reasonable (1,60?) foot times IF I can get it to hook. I'd prefer NOT to have to put Cal-Tracs (or, the others) on it if I can get by with just the S/S springs as it's a street driven car and I really don't want all that hardware hanging down in view unless it's totally necessary. But, I WILL go that route if I have to. Also, will Cal-Tracs work with my stock springs (if I have to go that route), or should I use Cal-Tracs AND S/S springs??? I'm pretty ignorant about this stuff, as to what to use. Can some of you A-Body Stocker gurus tell me which route to take with this thing? I'm lusting after a launch like the A-Body cars that run well in F, G, and H/SA bring to the strip, and am willing to spend a few bucks to get it. It's just a bracket car, so it will end up with a fiberglass hood, bumper, etc., and already has two big batteries in the trunk; none up front (the blower occupies the old battery space.) It's a shame to have the power to go low-to-mid 11's in the quarter and barely be able to break 12-flat because of traction problems. Any help on this issue would be greatly appreciated. Recommendations, please.... ???????????????? Bill |
Re: Hooking up an A Body Mopar
Quit screwing around and put the Calvert, mono leaf, rancho shocks and bars on. We did that on our car,
3800 LBS 12.05 108.00 1.52 in 60 foot first time out. Made 8 runs within .003 in 60 foot. My first set of mono leaf cal tracks set and I love them. Its a Dodge Coronet Wagon. Or Ill sell you my SS springs off our duster so I can put the Mono's on that car. Its a stock crate motor 360, 5.13 gear dana. Herb Jr |
Re: Hooking up an A Body Mopar
Some of us are still using SS springs, but the Cal tracs are the way to go on an all out race car. For a few hundred bucks you can try 3200# or 3400# SS spring, Mancini Racing has a good selection. Make sure you get the aluminum front eye bushings and lube them up well so they pivot easily on the hanger bolt. Get some 2 and 4 degree pinion shims and try them to see what works best. These go between the spring perches on the rear end and the springs. Most guys are using the Rancho 9 way adjustable shocks, get the ones for a Dodge truck, or you can use a stock shock with a shock extension on it. Make sure the shock has enough travel and does not limit the amount the rear can drop. Simple way to check this is to put the car on jack stands under the frame and disconnect the shocks and let the rear end drop as low as it can go, then see if the shocks extend past the lower shock mount. Throw the pinion snubber away, if the springs work it will never touch the floor.
Now that the rear is right it's time for the front, I won't get into it, but 6cyl torsion bars or the Mopar drag bars are a good choice. V8 bars have to much spring and will unload the back tires and cause spin after the launch. Good luck, let us know how it works out. George Mirza 1236 E/SA '71 Duster |
Re: Hooking up an A Body Mopar
Send me the chineese ss springs. My anchors have been eaten away by the salt water for my boat. Get the Cal Tracs;, mono leafs, shocks, and go fishing. 1.81. That's really bad.
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Re: Hooking up an A Body Mopar
Thanks guys.... Cal Tracs/mono-leafs it is... I won't waste my time with the "old" technology this time.
John Calvert is a genius, I guess.... For right now, I'll leave the front torsion bars in; that'll be a project for next winter. I think they're the 340 bars because this car was originally a 318 with factory air. I think they put the 340 bars in those cars. I have them "unwound" to the extent that the rubber bumpers are just touching (set very low.) Any suggestions on tires? I need something S-T-I-C-K-Y.... I'm tired of these turbo Buicks eating my lunch... Thanks again to all of you for all the good advice!!! Bill |
Re: Hooking up an A Body Mopar
"I won't waste my time with the "old" technology this time.
John Calvert is a genius, I guess...." John's "new" technology ain't exactly new. It's been around a while. But I do get your point. |
Re: Hooking up an A Body Mopar
Well, I think it's newer than the S/S springs... lol! That's all I meant.
Now, I need some 28"-tall, 9"-wide, 15" wheel-diameter slicks that are really sticky... Got any ideas? Anybody?? Bill |
Re: Hooking up an A Body Mopar
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Re: Hooking up an A Body Mopar
Terry,
Thanks for all that GREAT information!!! As you may, or may not know, A-Body sedans have smallish wheel well rear wells, and my Valiant is no exception. I really don't want to have to mini-tub this old crate; I think I can get by without that aggravation by running a 28"-tall, 9-inch-wide tire if I can find one with the right compound. The tires you were running won't fit this thing. I'd like to know what compound you had on those Hoosiers. I'd buy a pair of Hoosiers in a minute if they had a set 28"-tall I could use. That's an 88" rollout. My setup is rpm-limited; the chassis dyno showed that power falls off really rapidly after 5,600.... I think the engine is outrunning the blower about then, and boost goes from 10 pounds down to about 6 as it approached 6 grand, so I'm gearing it accordingly. That's okay; it'll live longer that way, and this is my daily driver. Thanks again for all the tire and suspension info. I think before I spend a bunch of $$$ on Cal Tracs, after thinking it over, I'm gonna put some really good tires on it and see how it hooks. If it still spins, then I'll attack the rear suspension with a vengeance... Bill |
Re: Hooking up an A Body Mopar
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Re: Hooking up an A Body Mopar
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When did they go overseas for the cheapies they sell now? Jim I use an entire '69 camaro with a ZL1 for a boat anchor, it'll only rust so far! |
Re: Hooking up an A Body Mopar
Terry,
Here' my engine: STOCK 360 Magnum short block EXCEPT for the cam. The cam specs are: 214-218@ .050"-lift, ground with 114-degree lobe separation. Gross lift at valve .525" Ground by Engle for Hughesperformance, a Mopar-only vendor with a dyno. HE says it's a good supercharger cam. Very little overlap. Stock hydraulic roller lifters with 300# open, Crane aluminum roller 1.6:1 (stock ratio) rockers. Heads; OEM 318/360 Magnum cast iron 1.94".1.60" with a 3-angle valve job and minimal valve bowl work; NOTHING else. TRUE compression with stock, dished, hypereutectic pistons: 9.00:1. Intake manifold: Professional Products 180-degree Air Gap ripoff, untouched Carb: Holley 4150, 750 double-pumper from the Carb Shop, modified for blow-thru up to 15 psi. ($900.00!!!) Ignition: MSD Boostmaster with MSD Blaster coil (all analog; no multiple spark discharge) Exhaust: TTI stepped headers (1-5/8" into 1-3/4") with 3 1/2" collector; 2.5" street exhaust with Dynomax Super Turbo mufflers Snowperformance BoostCooler alcohol injection system coming on at 3 psi of boost. Fuel: Avgas... probably 106-110 octane. Doesn't ever detonate, even at 10 psi of boost. Transmission: Len Schneider built 2.45 low 904 with a 2500rpm stall 318 converter (cheap!) As much low end torque as this thing makes, the last thing it needs is a hi-stall converter. Pulls like a freight locomotive at 2,500.... Idles fairly smoothly at 475 rpm and makes 12 inches of vacuum for the power brakes at that speed. 160-degree thermostat M-P "curved" OEM-type distributor. 3.55:1 Auburn limited slip, 8.75", soon to be 4.10:1. Moser axles coming very soon. When I put this engine together, a supercharger was nowhere on the horizon; I'd never even considered one. I wanted a car my wife could drive and she hates ragged idles; that's how that short-duration cam got in there. But, it only ran low 13's without a blower (I even had 340 exhaust manifolds on it), and that wouldn't get it. I spied a Vortech V-1, S-Trim new in the box on Ebay for a grand, and decided that that was the crutch I needed to pick this ol' tub up a bit. It picked it up about a second and a half and 17 mph.... It cost me a lot (about 4 grand) by the time I put the new half-inch fuel system with 2 pumps on it (main pump and a backup; I don't trust electric fuel pumps.) I have a 4" arm and a new set of rods for it... saving for some JE slugs right now. 402 cid will work. In the meantime, I can have some fun with it as it sits, IF I can get it to hook. That's what this is all about... Thanks for your time and all the good info! The cam is gonna stay, at least for now. Driveability around town is like a 2bbl 318... I like that. :) Bill |
Re: Hooking up an A Body Mopar
OK Bill......Im no pro but from what I know it is the cam that is causing the varience in boost. I would think that a cam with 112 centerline with a little more duration @ .050. Something around 230 degrees on the intale and 240 on the exhaust. The blower calms the cam down and will make it run fairly smooth. . When you go to a 402-408 inch piece you will need more cam. Larger engine needs more duration (air flow) because the cubic inches makes the cam think its smaller. The heads (Magnum) are OK but need some work. The exhaust is better (almost 30 %) than the old LA style head. Ive done quite a bit of playing with the 360 Magnum style heads in crate motored stockers and bracket cars. Also with all that instant torque it might hook better and the chassis will work better with the 4:10 gear. Im not an expert by far but just from what I have found over the years, In case a blower is not always a blower I can only say Ive worked on the DRAW THRU type and not the blow thru versions. Terry
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Re: Hooking up an A Body Mopar
Thanks, Terry. I do appreciate the time you took to think that out and write it.
I'm no expert either, and I hear what you're saying about the duration. I don't know much at all about turbochargers, but every Saturday I go to breakfast with a bunch of guys (8-10) who race Grand Nationals and they all have cams in the 210-214-degrees @ .050" range, even the ones who run high tens. Some have lobe-center separations as high as 116 degrees. Maybe that's a turbo thing, I dunno; as I said, I am no expert, but I know you're certainly right about a bigger engine needing more cam. This cam will never do for the stroker motor. Some of those new EQ heads would help a lot, too... Is there a bigger money pit anywhere, than a drag car????????????????????????????? For now, I am cash-flow limited and will get the Moser axles ($445.00) and some better slicks (another $400) and bolt in that 4.10 and go racing. If I can't run some 11.30s, shame on me!!! :( Oh; I have a big U-joint driveshaft in the works, too... I still have the small U-joints in the one I've been using and I feel like I'm living on borrowed time... LOL! |
Re: Hooking up an A Body Mopar
Since your not limited to rules you should try the Edelbrock Alum. Magnum heads when $$$$ is avaliable. They already have 2.02 intake valves, lighter weight, use chevy valves and rocker parts and flow pretty good out of the box. Just be sure to check the C.C.s. They are not even close out of the box in that dept. In the long run they are cheaper than modifying the iron heads. We had to use a larger drive shaft also (3720+ lbs). Used the larger joints and a 3 1/2 shaft. Never lost another one. Again Im not that up on turbo engines but Ive heard they are camed differently than a blower engine but boost is boost. It just comes in at a different RPM range. Food for thought until someone who really knows could help you out. Terry
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Re: Hooking up an A Body Mopar
Terry,
I'm not limited by rules, but I AM limited by $$$$ and the EQ heads flow about as much as the Edelbrocks for about half the price. The reason the stock heads are on there is that I am always cash-poor, it seems, and I have to do this thing one step at a time... being retired, and with a disabled wife who needs 24/7 care, I can't just go out and get a job to make money for this little pissant race car project. So, I have to do what I can, when I can... I'm sure you understand. I've got a 4" crank and a new set of rods for it... just need a new set of reverse-deflector, 8:1, forged, J-E pistons, so the piggy-bank is IN OPERATION, but there again, it would be an exercise in futility to put the long arm in without a better set of heads.... so, I decided to try to get it hooked up, first. I'll build the big motor next year, with any luck. There's no end to this... is there? LOL!!! After doing it since 1955, you'd think I'd learn, eventually... I saw a bumper sticker on the back of a trailer once that said "CAUTION; THIS TRAILER CONTAINS A DISEASE FOR WHICH THERE IN NO CURE." There was an NHRA decal beside it... LOL! Bill |
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