First time at the strip!

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MopaR&D

MopaR&D

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I finally got the chance to take my Duster to one of the Test and Tune nights at Bandimere Speedway near me... What a blast! With the engine in my sig I ran a best (out of 2 runs) of 15.3 sec. @ 93 mph. This is with a stock 7 1/4" open rear with 2.76 gears (and BFG street tires), 904 trans (with 2500 stall converter), AFB 625 carb, factory-style dual-snorkel air cleaner, and Hedman Tight Tube headers into dual 2.5" X-pipe exhaust.

Obviously the rear end is the biggest limiting factor, I didn't even get out of 2nd gear by the time I hit the traps!! 60' times were pretty bad, 2.34 seconds...! I have an early B-body 8 3/4" rear waiting to go in, how much quicker would my car be with 3.55's and sure-grip (and street tires vs. slicks)?

Also I think my engine could use a bigger carb (I'm thinking Holley 670 Street Avenger) and open air cleaner, how much would that give me? Lastly I have a 284*/.484" MP purple cam lying around, if I swapped that in how much quicker would the car be vs. the small Voodoo cam that's in it now?

Just bench racin' here guys any and all comments welcome...
 
well, to help with your questions, we'd need to know a little about your duster. What engine do you have, and what current modifications? what size is the voo-doo cam? Automatic or 4 speed? stock suspension or modified? etc.
 
OK let's see...

Engine is what's in my sig plus what's in my first post, also RPM Air-Gap intake. The cam is the 60401 Voodoo by Lunati.

Trans is 904 automatic with 2500-stall converter, supposedly has a shift kit but doesn't feel too different from stock.

Rear suspension is all stock (including sagging leaf springs), with very old shocks. Front suspension has 1" torsion bars from Just Suspension and was rebuilt with offset bushings for extra caster, also with old worn-out shocks. I'm pretty limited on funds so I've upgraded things slowly. Took me almost 2 years to save up all the parts to build and swap in the 360...
 
well with a Small block you should be running faster than me...

the small block guys should know off the top of their head but where does it seem to "lay over" meaning it runs out of power? i imagine its around 5600 or so?

what are you shifting at and what is your trap rpm?

P.S. now that you have the bug to go fast your gonna really have to learn the ropes! go buy a note book just for that car... log all your runs and changes... this will allow you to see if your getting faster or slower...
 
well in my opinion, it seems you should have enough engine to run low 14 second times with some better gearing...Maybe some 3:91 s or so. I think the 670 street avenger is a good choice as I have a 770 on my duster and it runs great, and there easy to tune. As much as I love my voo-doo cam in my car, I think you could definitly bump up the cam size, to maybe the 60403. I have run plenty of purple shafts in the past with good results, but the voo-doo line of cams pull harder....without a dought! Are you using a good electronic ignition system?
 
True but also consider (forgot to mention) this drag strip is at 5800' above sea level.

The power seems to taper off just over 5000 RPM which is where I was shifting. The cam is supposed to be good to 5500 RPM, I haven't tried winding it out that much yet. It doesn't really "lay over" per se, the torque just seems to kinda level off.

fanofpetty: Yes I'm using a Mallory HyFire-6A system with factory electronic distributor. Timing is 16 initial, 35 total around 2500 RPM. I would love to try the 60403 cam, I already have this purple shaft cam though so I might swap that in first just to see how it does.
 
I would leave that carb if this car is mainly street-driven. 3.55's (with a street tire) would pick up a second.

A converter would be where I would put money, after the gears.
 
yeah....thats a good point........at 5800 feet. Yeah, try the purple shaft...see what it does. It seems you've done quite a little to the car, except for the rear suspension. superstock springs or cal-trac.s would greatly help in getting it hooked. Of course if your leaning towards a cornering type machine you don't want superstock springs...LOL!
 
Have you figured out the max timing the engine can handle. IIRC, when in altitudes like you are, the engine can handle more total timing than something at sea level. The initial side seems in a good range.

A better carb could pick that combo up by 2-3 tenths and a few MPH. I'd put a double pumper on it, that's JMO. Drive it sensibly and it will get good mileage.

60' could be much better. Need to be able to mash it at the go. There's at least .3-.4 in time there alone.

I'd work on what you have and figure out to make the current combo go.
 
Change one thing at a time. Start with the rear. The 3:55's would be great for your combo. You'll probably pick up .8-1.0 seconds, even at that elevation. You can't upgrade your cam until you change the gears anyway. If you up the cam now it will be slower. You should have 1.6 rockers on the magnums so that's already helping a little in the upper rpm range. If you go to a new carb go with the 770 avenger. I'll bet the jetting will be real close out of the box. Leave the worn out front shocks on the front. Put in a cheap shift kit and go out and test&tune it after each change.
 
I'll guess it's making about 260hp at altitude, so it's not that far off for MPH.
 
Power starts falling off after 5 grand, are the valve springs good--if so, it needs bigger heads

edit..oh, its a 360, not a 318, heck put in new valve springs and let it rip
 
Honestly, IMO, your run is pretty good. Just out of curiosity I looked up the altitude correction factor, and your run at sea level (according to numbers anyway) would be 14.17 at 99mph. I had a 72' 360 with a 70' 340 intake, crane 224/232 .460/.450 cam, headers, 600 carter, 727 with a 2600 stall and an 8 3/4 with 2.76 gears, and I ran a 14.2 at 95mph at a 1200ft elevation. My 60ft was 2.2. That was right out of high school, I changed some parts and about 8 years later ran again. Same bottom end, pocket ported the J heads with new valvesprings, windage tray, LD340 and 750DP, 904 with a 2800 stall, and 3.23 gears. Dropped to a 13.5 @100. I went to 3.55 and didn't see any difference other than using more gas.
 
Sounds like you've got the bug. I was at a Ford race day this morning at a local track with my Mustang son. These kind of events bring out the first timers and those who think they can drive there hotrod on the street but look foolish at the track. Sounds to me like you did great and most importantly had fun. If you get your car working and can get it running consistently there's nothing like going rounds and winning one of these things. Keep up the good work.
 
density altitude = 9089.84 ft this afternoon in Denver...kinda hard to run fast....
 
Work on that 60 ft.Gears ,double pumper,street tires.You have a nice engine combo.X2 on the log book,that way you don't backtrack where you been.
 
metallidart said:
Honestly, IMO, your run is pretty good. Just out of curiosity I looked up the altitude correction factor, and your run at sea level (according to numbers anyway) would be 14.17 at 99mph. I had a 72' 360 with a 70' 340 intake, crane 224/232 .460/.450 cam, headers, 600 carter, 727 with a 2600 stall and an 8 3/4 with 2.76 gears, and I ran a 14.2 at 95mph at a 1200ft elevation. My 60ft was 2.2. That was right out of high school, I changed some parts and about 8 years later ran again. Same bottom end, pocket ported the J heads with new valvesprings, windage tray, LD340 and 750DP, 904 with a 2800 stall, and 3.23 gears. Dropped to a 13.5 @100. I went to 3.55 and didn't see any difference other than using more gas.
Click to expand...


There you go.

I believe you can run more compression at your altitude

True about gearing, around 3.23 is it for the street, if you need more gear best to go straight to the 4.10 gear...maybe 3.91's with a 360 extra stroke
 
Thanks for all the tips guys, yes I would say I've gotten "the bug"... I was ready to do 5 more runs that night if the strip hadn't closed lol.

crackedback: I haven't tried messing with the timing yet, I don't think it can be increased much as I get a bit of ping if I hit the gas in high gear on a hot day. I'll keep that in mind though.

dodge freak: I put in new valvesprings from Hughes when I built the engine; it has all new parts except for the crank and rods. I know the valves aren't floating, I think it could just use a little more flow in the heads (stock Magnums with no porting). Also the exhaust downpipes weren't made very well so they're kinda crushed and restrictive, could probably pick up some more top end with bigger header collectors and pipes with smoother bends. Compression is already at 10.5:1 too and I think that's the max I can go without getting a cam with more overlap.

Overall seems like the first step is gearing, rear suspension, and tires... 3.23's would be spot-on with this cam which makes a lot of low-end grunt but a bigger cam could make better use of 3.55's I feel. The rear-end I have waiting to put in has 2.94 gears with sure-grip so I'll probably get a whole 3rd-member with a set of 3.55's to swap when I take it to the strip.
 
Been racing at that track for 30 years. You need some more gearing, other than that you combo should get you into the 14s up here.
 
4.10 used to be the MIN gear for a hot street car, there was a good reason for that.

I have old DC catalogs, 4.10 and looser was the only gears they sold, not even 3.91's let alone 3.55's

People are afraid to use a 4.10 or looser gear and then they believe they need more stroke-torque, nah, just more gearing

I got 3.91's and 26.5 inch tires and my ride doesn't have enough gear. 1st seems alright and 2nd really moves but I can tell its being held back. 4.30's would feel like another 30 hp
 
True dodge freak but I drive this car on the street and on long highway trips a lot too; last month I took a 7-hour road trip to Telluride, CO through the mountains and it was SO much fun. The acceleration with 4.10's would be crazy but I feel like with the torquey low-RPM nature of the engine it would wind out too fast and not do much better at the strip than some 3.55's

I would imagine "back in the day" it was easy to get taller gearsets because they were offered by the factory, so it wasn't necessary for the aftermarket to offer them. Also most performance cams back then had a lot of overlap so you'd need the gear to help it wind up. I bet my car would scream with a set of 4.10's and that MP 284/.484" cam I have lying around.
 
Have two sets of gears one for week 2.76-3.23 and one for the weekend 4.10-4.30 it's a little work but you have too pay to play.
 
Another way is to make more HP at the same or lower peak rpm your car will go faster there for need less gear, a shot of Nos and 3.23-3.55 should work.
 
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