Best 1/4 mile combo's???
 

Okay guys, Post your numbers. I've been doing a "casual" survey just by looking at posts, but am interested in hard numbers in different combinations. It seems that when talking strictly 1/4 times, the BB guys don't really have anything over the SB guys. But maybe I'm wrong and have just missed the BB guys' posts. (?)

As you know from my previous posts, I'm contemplating dumping my SB in favor of an FE. I just want to know that the swap will give me more than a nice sound and a cool look under the hood.

What I'm interested in is what dispalcement, block, & gearing you're running and what you can squeeze out of it.

Thanks, Tom

The original comp cars ran a 3.73 rear ratio and a close ratio 4 speed top loader. Typical 1/4 mile times, "back in the day" were 12.2 or so. The 289 cars were real close to that, 12.4 maybe? The top speed was WAY different with the FE going substantially faster.

My 427, 3.31 rear gear and close ratio top loader runs:

11.90 at 121.27

I don't shift to second until about 65 mph, so it's a HIGH gear combo. But many Cobar owners have found a LOW gear combo is useless at the track due to traction problems. Their best ET is often obtained by using 2nd or even 3rd gear out of the hole!

Thus, makes a strong case for the high gear ratio I'm running!

I don't recall the original small block Cobras running quite that quickly back in the 60s. On street tires, low 13s were more likely. My 427 ran a best of 12.05 at 116 mph with virtually no traction in first gear, this with a 3.77 (not 3.73) gear.

Tom: What kind of times are you running with your SB? You can most likely expect low 12's / high 11's in a FE, unless it's REALLY built..........and you're a pretty good 1/4 mile driver. I have a pretty well built FE and was running high 11's with a lot of wheel spin. Started launching in 2nd gear and my best ET was 11.78 @ 128 with traction issues still happening. I'm thinking of changing tires from my BFG's to either the Yoko's or perhaps the BFG drag radials, or even the big lettered GoodYears (but they are non DOT).
If you really want to get down the track in a hurry, go with an alum Shelby block and put some Keith Craft stage III heads on it. I don't have an alum block, but I'm planning on sending my Edelbrock heads in to Craft and have him sprinkle some of his magic dust on them.:D

I think Colin has you with his 8.44 time.

Very impressive.

Only 3 trips down the 1/4 mile and the best time I could muster was 12.7@110 mph. That's with a mildly built 428, 2.88 gears and a Richmond 5 speed. Tires are Michellin Pilot Sports 335/35/17. Like others have said, lots and lots of traction problems.

Chris

Best time with a worked 351W was 11.40 at 121mph with 3.73 gears/Tremec/15" BFG DR's, launch at around 3200rpm ,granny shifting as fast as I could . Sixty foot was not working. Past attempts after a practice run, if 60 fts can hang in the 1.7's is mid/high 11's ranging 118-122 mph depending on psi. Three years ago Roll Out (21psi) versus Launch (15psi) on that same day showed 12.0-1 at 120 mph versus 11.54 at 118mph. The launch showed lower mph (psi) but 3-4 tenths gain in 60ft made the difference. This season I intended to try power shifting , learning better launch techniques but budget reality crushed that enthusiasm and driving home became the bigger thrill .

Stock 1989 5.0- changed EFI to 750 carb. with matching 1989 T-5. hooked to 4.10 rear gears. 11.8-9 112with slicks (1.65 60ft) street tires 12.20s 109(1.75 60ft) Runs all day on pump gas. Been waiting for it to give up the ghost so I can put my good motor in but this little 302 takes a lickin!

Dragonsnake........
 

The 289 dragonsnake cobra's held the national record for years,

11.9 ET

high reving 289, 4 speed, 4.86 gears. nothing could touch it.
Perry.
ps- my smogger 460 cobra has turned 11.92 on 87 regular gas.:cool:

Mid 12's for the original 289 Cobras is likely in my opinion. Thats based on what I see today with STOCK 302 replicas. Low 13's is the norm, with any modifications at all your in the 12's.

Generally speaking the original cars were lighter than just about ANY replica out there, and they certainly had more h.p. than a modern stock 302. I'm running BIG letter Goodyears, the traction is VERY good.

An early issue with the 260 Cobras was dissapointed owners when the car did NOT meet the acceleration numbers "promised". Those numbers were obtained by Shelby running a VERY modiifed high horse power 260 and the early "production" cars received a much more mild version. The initial Shelby solution was a lower rear gear.

My guess is a SB will get the hole shot on a big block. But MY big block just keeps pulling REALLY strong well after a 100mph, when the small block starts to struggle. THATS what makes the mph speed so much different while the ET stays fairly close.

Perry,

Make that 11.81 at 116.27MPH for the 289 Dragonsnake, both NHRA records.

Hal

From all indications, it looks like I'll be sticking with my 289. I've never run it, as I've only had it a few months, but the P.O. claimed that his one run was very impressive. I won't post his claim here, as I'm not sure I believe it myself. I do know that it will leave my BB Corvette in the dust and that car turns consistent 12:20's.

Anyway, thanks for all the replies. Other than having to look at all the disappointed faces when I tell folks that it's "just" a 289, I'm pretty hapy with the combination I have. I think that the 4.57 rear is this car's largest asset when it comes to rolling it on. A big block will just cost me money and likely not get me anywhere.

Tom.

Ok here are my times as of last weekend at a new dragstrip here in Tulsa:

Vitals: 428 CJ .030 over, 10.5 : 1 Comp, solid cam 592 lift 232, dur 750 Speed Demon Carb, Sig Erson Roller Rockers, Top Loader 4sp, 3.50 : 1 live axel differential, Goodyear Drag 27 " slicks

Before this weekend my best time was an 11.82 in St. Louis last year (runner-up in the Quick 8's).

Warm up pass 12.01
2nd pass 11.86
3rd pass 11.79
Dialed in at 11.78 broke out at a 11.701
I think if I switched back to my 3.73 : 1 gears I could get much lower assuming I could get my tires hot enough quick enough.

Clois

The first car I built I had the dragstrip in mind. Only ran it 4 times. It was a CR, 427 side oiler, 11.5 to 1, dual carbs, 100hp nitrous. 9" Ford with 4:11, roller C6 auto. 11" slicks. Best time was 10.20 @ 137 with the nitrous. It hooked hard and got pretty loose at the top.

The car has gone through 4 owners and 4 paint jobs, 5 motors, 3 sets of wheels, new suspension, new gauges, 3 sets of sidepipes, and numerous other changes. It still has the same trans. The car is 14 years old and has about 75,000 miles on it. It looks better than the day I sold it. This winter the owner wants to add stack fuel injection to the side oiler. All the changes were done at the owners request throughout the years. It's now a daily driver. Quite a history building on the car.
Don

My car was slower with the 427R as delivered before I spent a pile of money to change a few things listed. I believe the Superformance exhaust is the most restrictive part that I change, but the Pro-Systems carb also made the car come alive.

The video pass in my signature is starting off idle with a 1.7 60ft time, 10.7 @130.6 mph. The track had a nice hook with the drag radials. Note the car is rock solid and straight with an effortless pass. I did that twice in a row and then went home. Keep in mind each .1 sec off 60ft is good for about .2 at the end, so there's no need to thrash the launch. A realistic slightly aggressive start 1.5 60ft time would put the car in the low 10s, but there's not much point in being aggressive. MPH remains about the same either way. On motor only, no power adders, I believe the combination I have is favorable performance wise to most big blocks given the small block is less weight and generally makes more power per cubic inch.

Superformance, stock suspension
Small block, Roush 427R single plane intake
Pro-Systems carb
2 inch primary headers
Buckshot Racefab side pipes
8AN fuel line
mechanical fuel pump
3.73 rear end
stronger half shafts
Detroit Tru-track in Ford 8.8 IRS
28 inch tall Mickey Thompson ET street drag radials
light weight flywheel

times
 

best time on street tires mufflers off was 11.01 at 128 and i killed the tires in first, 373 gears and a custom aode behind a 427 stroked with factory carbs,
i have a set of slicks for this year but im affraid ill be puking axles so i am leary
to use them.

i went 10.60 @127 mph with my 351w (383ci) and 5 speed on dragradials and got kicked off the track for going to fast. its still got a got bit left in it!!

Getting off the line
 

tpiini Tom There are a bunch of guys in the 10.20 at 138.0's mph. Wayne Turpin with a 482 stroker. Keithcraft ran 10.20's with his Kirkham 527. Dave Sal ran 10.28 with a webered 482. Stacy P is the only stock body cobra to runin the 9.0's with a TP 433 ci. and a 150hp of nos at 9.87 at 139.0. He was running a 3.07 rearend stock. 4 spd trans. There are stretched race cars running in the 8.9 field. Double Vemons first Viper motor car was in the 10.0's. Short wheel base makes it hard for cobras to run the 1/4 mile. You also have that sail on the car too( windshield). There was to be a guy last year with a cobra to run 9.0's but breaking a timing chain stopped that. Just A6 on CC here has run in the low 10.30-10.40s with a V6 chevy power cobra. The problem is not big block or small block, it's hooking to the track and going. There have also been 4 spd, 5spd, 6 spd and automatics running the 10's. IMO if you get a soft-loc clutch assembly for your car and can dial it in, this is the best change for a 9.0 second run. I have run 12.5 in the 1/4 mile with 3.31 gears, 452 9.2 compression motor with a small camshaft, and come out of the hole at 1,300 rpms. Tires are 335/35 17" pilots. This is the tuffest event on a drive train. The cobra was not designed with an IRS setup to drag race. Tom, If you are going to drag race your car alot, get a cobra with a 9" rearend and 4 link suspension setup. Use a small 9-10 wide slick. Put on a space suit too, I have seen many cobra lift the front wheels and sometimes hit the walls, and this happens FAST. Rick L. Ps there are cars that have run nines with STOCK looking bodies, no windshields, and power adders. I don't count them for a stock body cobra. The cars above are all street driven on the road, not race cars that look like a pro street car.

i am changing my heads, cam, intake with the goal of going 9.90s all motor driven to the track:D

I suppose my Cobra may be the fastest in the world. 7.96@170 mph. Street legal, tagged,and insured. Should improve a few tenths this year.