your thoughts

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I can tell you from first hand experience that you can get that car into the 12s and still have a reliable street macine. First off is the gear. If it's not a hiway cruiser, stick a 4.56 in it!!! Good breathing intake, 750 carb, headers and you don't Need a massive solid cam. Something around .480lift and matching valve springs and you're easily there. Of course this is assuming your engine is healthy and you have a good stock electronic ignition. An adjustable pinion snubbed and some basic tuning, youl be home free!!! Seen it done many times!!!!!
 
AJ/FormS said:
Howdy neighbor!
No problem.
Stock street suspension, or race. Springs and slicks are bolt-ons right?
The Dc manual says 12.4s require a Power to Weight ratio of .100 with race suspension. Street suspension may be up to a half second slower, due to the 60ft challenge, and the 3.21s.
So back to the .100 p/w
How heavy is that car? let's say you get it down to 3500 race weight. Well then; 3500 x .100 =350horsepower. The Dc folks work off crank power so, 350 is the target. Lessee 360 cubes,350 hp, that's .97 hp per cube. Ok maybe that's a lil tuff with bolt ons.
Since these engines seem to be 245 hp factory rated, we need 105 more hp, to just sneak into the 12s with street suspension. So I think we better bolt in some springs, gears and slicks. That reduces our p/w requirement to about .086, to just sneak in there.
Ok then 3500 x .086 =301hp; now yer talking.
This is doable with just a few other changes
This combo wants to hit a hair over a hunert so 4.30s are the go to gear. They will get you 102 at 5500 with 88s(28 inch tires) and 5% slip.
The 5500 trap points to a power peak of about 5100, and that points to 340 cam. Go get'em!
Arm-chair at it's finest, just suck it out of a book.
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Your say he needs 350 hp and is 105 hp away from whats needed cause the stock hp is 245 hp. The only problem I see with this is there are two different ratings going on here gross and net. The 360 probably makes closer to 300 gross hp so he's only about 50 hp off his goal.
 
273 said:
Your say he needs 350 hp and is 105 hp away from whats needed cause the stock hp is 245 hp. The only problem I see with this is there are two different ratings going on here gross and net. The 360 probably makes closer to 300 gross hp so he's only about 50 hp off his goal.
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He is probably a little more than 50 horsepower away. This is a combination we found for 300 flywheel horsepower from a stock bottom end 360..........

Let's put a mild 8.2:1 360 on the dyno.

I'd be looking for better cylinder heads and a touch more camshaft than this. The headers? Well we tested TTI's vs the cheapo Summit headers on a 600 HP small block and found about one horsepower difference average from 3,000-6,000 rpm. After 6,000 rpm the TTI headers were better.
 
oldkimmer said:
.............I'm not really concerned about running on the street as the last 5 years it has only made 600 miles......kim
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I'd run the 4.30s. The heads will either need some work (spring seats, guides cut down, matched springs, better retainers and locks) or outright replacement. Cheapie headers are all that's needed. A dual plane intake, a carb at least 750cfm, a cam with some lift and duration, and you'll have what you need if the suspension has a few new parts and is setup right. Something like that should go mid 12s pretty easilly.
 
There can be a half-second or more in the 60fts alone between SuperStock suspension and street.
More time lost with the wrong trap gear,and more again with a street TC,and more again in street pipes vs Open headers.
My 367-FormulaS clone, 60fts at 2.2, and takes 7.92 seconds to hit 93 in the 1/8. I love that it can hit 93, but the ET is kindof disappointing,lol .
My street suspension and 3.55 are staying.
 
as Wallace see's it>
3500lbs at the line, 316fly hp, 26" slick, 4.10 gear and a car that will hook>
Power to Weight Ratio: 11.08
60 Foot E.T. : 1.80
1/8 Mile E.T. : 8.19
1/8 Mile Trap Speed : 82.97
1/4 Mile E.T. : 12.98
1/4 Mile Trap Speed : 103
1/4 Mile Trap RPM : 5,472+5% slip?
Can't see making that sort of power with just a cam+bolt-ons at 8.5:1CR

My old stock street '71 340 Cuda (2.02 heads), full interior etc..3500lbs+
727, 3500 B&M SH verter
Dual plane int., 750 Holley
.484 purple hyd., small open hdrs.
stock susp. w/clamps on fr of rear springs
3.55's, 8x26" slicks
= 13.3's@101 = 300 fly hp
added>
Holley SD int. 850DP
DC. 590sft cam, 1.75" race hdrs.
4.30's, 4200 verter, f/manaul trans
rear shock extensions, adj snubber, 10x28's
= 12.39@108 = 370 fly hp., max rpm 6200
for reference.
 
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Thanks guys. I have an 8.75 with 4.30 gears. And 28x9 slicks. Also a 3ooo or so stall. I would need to get an alum intake and headers I also have a 750 carter competition carb or an 850 street demon. Kim. Hope this enlightens u guys. What cam ?would work best
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A 12.9 with SS suspension is around 103mph.The 4.30s will hit that at 5133rpmPlus TCslip,say5400, with your tires.
With street suspension, you would need to aim for a 12.4 which would be around 107mph. the 4.30s will hit that at 5333+slip,say5600.
To trap well, you might want the combo to power peak say300 to 500 rpm lower, or 5250.
Now you're getting into trouble.
In post #8 the math puked out 350hp, and the 4.30s want it at 5250.
Is it doable? I think so, but just barely. It would be easier up around 5600/5700 but that combo will want different gears.

The peak at 5250 is about a 225ish cam
The peak at 5700 leads to a 240ish cam
Sound about right boys?

The 240 cam will take your street suspension down into the mid 12s, cuz now your making closer to 400hp, perhaps a little over, depending on your headwork.

So as a compromise a cam of around 232 could get you a peak around 5450, and then you won't be overdriving your gears too badly.And still firmly into the 12s. You will have trouble 60footing it.The 230/235 cam has made over 400hp.
In a 3500pound raceweight car 400/3500=.114 which puts you down at 11.8seconds with SS suspension,12.3ish with street suspension.
And the accompanying mph is 113ish; which might be 5632 plus slip,say 5900. I'm seeing success with the 232ish cam.

As an aside my pig-heavy Barracuda(3450 me in it, and 200 pounds of stuff stripped off it) went 93 in the 1/8th@7.92 with a 2.2 60ft. Somewhere I once read that you can take your Eighth mile ET and multiply it by 1.57 to get an idea of the 1/4 mile ET. Well if that is true, then my car is a 7.92x1.57=12.56 second car;with the 2.2 60ft and all. But even if the 1.57 is just close, the car is still firmly in the 12s.
My 360 has a 230cam,is a zero-deck, and has OOTB Eddies.Well it was a zero deck; the pistons are now .005 up,or so.That makes her about 10.9Scr.
Go man go!

Ps, very streetable, even with a 4-gear.
I have a 10.97 starter gear tho.......... She will idle down to 600 with the clutch in and her pulling. After that I kinda have to put a lil slip in the clutch cuz she's losing torque fast.I can mash it at 2500 and light up the 295s(750DP). I think I can mash it at a lower rpm, but I've never really looked at the tach,lol. 2500 in first is 30 mph and she definitely lights em up at 30. I bet she'd do it at 25(2100) or maybe even 20(1670). Heck she'll do from a dead stop with a bit of a burp on the throttle to put a bit of inertia into the flywheel,lol. Point is, it is very streetable. It vacuum peaks at around 2200, and that is what I have her geared for at 65mph.(GVod). It ain't great on gas but I think she is now as good as I can make it.
Big street-fun.
 
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All good stuff AJ,.....but a stock 8.4:1 (1974) 4bbl 360 is around 245hp? at best, adding lets say an XE268-274, hdrs, 750 carter, and an rpm intake ain't gonna make 315hp which to me is what it needs to just go in the 12's@3500lbs at the line and thats assuming you got a good rear set up that can 60ft, thats still only mid>lowish 13's as I see it with bolt-ons. Now if you mill the heads some and do a mild clean/port/good valve job on the heads or better still bolt on a pair of stock Eddys then probably yes....the 850 Demon set up well should be worth a 1/10th as well even on such a mild tune motor, I lost 2/10ths going to a 750 from the 850 cos everyone was telling me my carb was too big, but thats a slightly different set up....just my 2 cents.
 
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My thoughts are...why, why bother...more than just my experience says you're just gonna find out what let's loose first before you ever go lower than low mid 13's.
40 year old stock bottom...those bearings, so many winter cycles...moisture. Too many of these "only drive 500 miles a year for the last decade or 3" have the bearings corroding right under your nose from the lack of oil change, running them, and that dampner....waiting to spin at 5500+ shift and help throw the guts out of it.
My thought as well....is this thread is nothing but a conversation piece. Best of luck ol'K.
 
I don't know. I think as long as the rpms are kept under 5500 it will be fine. I guess it depends on what the usage will be. If this is a bracket deal, every weekend type thing, then yeah it should get rebuilt or replaced with something that has been. If this is a once or twice a summer it will probably be fine.
 
oldkimmer said:
........I have a 75 duster factory 360 4bbl, dual exhaust, 727 with factory hi stall converter and 3.21 sure grip......40,000 original miles.......I want to make it into the 12s.....can it be done keeping the factory long block in it with some bolt ons?..........thanks.........kim........
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Oh yeah, I lost sight of that....sorry KiM
You will be having trouble getting air into that beast.
Unless you supercharge it; pump,Turbo,or N2O.
You still need to hit the same target; I think it was .100 P/W.
So if you are able to get the power up to 290,then you will need,290/.100 = a race weight of 2900.That's at least 250 pounds to shed plus your weight. The 250 is not that hard; it's the last 195# in my case,(at that time).
On my car;The dual full-length 3'' pipes and Dynomaxers are 72#, the rear folding seat is 64#, the bumpers were 60#/pr, the sway-bar about 18#, and the heater box without liquid was 16#; for a grand total of about 230#. No A/C, battery in trunk. I kept the P/S,P/B.I got us(me,the car,the GV, and the non-negotiables) down to 3467 for that 93mph blast. I didn't even try for the last 195#.....lol

Dusters start out a lil lighter,than 2nd gen Barracuda FBs, but 75's are a bit porky. 2900 car and driver, is gonna be a lil tuff :(
It'll be fun trying tho, :)
I think the DC bulletin #40 must be in the ballpark. Here's why:
My car went 7.92@93 in the 1/8 @3467 pounds raceweight, with a 2.2 60ft.
If you deduct a half second from my 7.92, to make my car appear to be a SS suspension car (so it fits into the bulletin parameters), 60 footing at 2.2 less .5 =1.70, and then my 1/8 ET might be 7.42, and grossing that up by 1.57(the previously mentioned conversion factor) then my car might ET at 11.65 in the qtr. To ET there requires a P/W of .120. Since we know what my raceweight was on race day, we can compute the hp thus; 3467 x .120= 416 hp.
Now,I have never dyno'd my combo. But Hughes built one very much like mine and called it Brett's Combo. Theirs dyno'd at 437/437; so I think I must be in the ballpark.
And therefore, I think the bulletin must be correct, and my combo must have a little more in her. I showed up at the track, dropped my exhaust, bolted on my DRs and moved to the back of the line. The 7.92 run was one of 4 that day, and the only successfully completed run.So was there more in her? Who knows, I was happy running what I brung!
And you will be too. The thrill of knowing what you are doing is perfectly legal, and you don't have to JAM ON THE BRAKES,HARD to brake from 93 to 65 just in case the man is hiding somewhere, well that is a thrill indeed.
Good luck!
 
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I guess we will see what happens in May I will at least have the 8.75 with 4.30s in with decent rear springs and long shocks. 28x9x15 slicks. Prolly carb and intake maybe I'll have the ambition to change the converter and a manual shift kit. Kim
 
Bring it over...we will have it running 12 in a couple of weeks...No Problem....
 
It will go faster with it, or you'll grenade it. You certainly don't need any kits to run the number you want to. Factory heads, even bad ones, can move the air you need to to make the steam required to run the numbers in a race-matched combo. Not in a street car combo, but with deeper gears, if it can hold together (and I think it probably could if it's a servicable lower end) you're good.
 
If the car's an investment - I'd agree. But at that point, aren't you doing more than bolt ons? ;)
 
Sorry for the late reply. I do appreciate all the reply’s. My daughter raced it 2 days. This is a base line run leaving it in drive and letting it shift on its own at 4500 rpm. 15.95 60 ft 2.44 Speed 89.1 mph With 26 inch street tires. With 28x9x15 M/T slicks same 15.94 60 ft 2.21 speed 89.3mph. I thought that being 2/10ths faster in the 60ft it would if picked up on the top end. All bone stock. 3 runs with street tires and 3 runs with slicks. Kim
 
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Only 3 seconds to go and she’s in the 12s! Daddy better get off his wallet!
 
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