Just wondering if anyone here has a 383 in their 70-72 Chevelle that runs 11-12 second 1/4 mile times? How did you manage to do it? And what is your car's weight and combo? Also what is your engine's output?

I'm beginning to wonder if an all throttle no bottle naturally aspirated stroker can be made to push a 70-72 car into the 11-12's while still running on 93 octane and still have enough vacuum for power brakes and such.

While not a Chevelle, I think Eric68's 383 Camaro runs 11's, and it's NA last time I checked and runs 93 octane to and from the track (at least I think so).

I have a 388 stroker(bored 60 over). It runs 12.00 in the 1/4 mile all engine,11.50 on a 50 shot of n2o, and low 11's on 100 shot of n20.

Car: '67 El Camino (3200lbs with driver)

Engine: Chevy sb 4-bolt, Camel back heads (polished and ported), Comp Cams XE 284 hyd. flat tappet cam, erson roller rockers, Air Gap manifold, 750 proform carb, 3/4 headman headers, Summit turbo mufflers with cut-outs, Speed Pro Hyp. pistons (11:1 compression with 67cc heads, timing 36 degs total. with and without n2o.

Transmission: TH400 with quick silver rachet shifter, shift kit, and Summit 3500 stall converter.

Rear end: 12 bolt, 4.10 gears, SSM lift bars, tail gate removed and replaced with net.

Ingnition: MSD ignition with MSD distributor.

Fuel system: 140gph Holley mechanical pump with regulator (runs and races on 93 pump gas).

Front end: Inner fenders removed, 90/10 shocks

N20 system: Edelbock 50, 75, 100 shot

Tires: 26" Hoosier slicks with a 9" tread

That about does it for my car. Click on the following link if you want to see it run. It is 11 megs. If you don't have a fast connection just right click and save target to your desktop. This was last friday night's action. My car is the yellow el camino and there are 3 of my runs on the video, as well as some of the other cars that ran that night.

http://www.dwebs.lunarpages.com/Mark_Stuff/03-04-05%20Royal%20Rumble.wmv

Our track's website is Http://www.edinburgracetrack.com

I am the web master.

I hope this helps!

Danny

My 355 runs 11.50 NA. It took some doing, though. I have 4.56 gears and wind the engine to 7000 rpm. I have removed all unnecessary weight from the car. It weights 3180 wet (20 gals of fuel) without me (3365 with me). With a 383, 4.10 are better since it makes more torque and doesn't need to wind so tight to make power. Specs are linked in my sig. 91 octane.

Danny, how did you get your Elky so light. I'm inner fenderless, too. Any glass?

Although not a Chevelle and barely in the 12's it does have a 385 NA that runs on 93. The car is heavy, all steel, stock interior (4100+#) and a mild 3.36 gear. I would guess my engine combo with more gear in a lighter car would get you in the low 12's. Engine combo:

385 s/b
10.25 comp
pro topline iron heads with 200 cc/ 64cc CC
Cam Motion hyd flat tappet 240/242 @ 0.050 512/490 lift w/ 1.6 rockers on the intake
Elde air gap RPM
Speed Demon 650 mech box stock
Accel HEI with crane hi-6
Trans is a 350 w/ Coan 11" 3000 stall

I know the cam profile looks weird but I called the guys at Cam Motion when my engine was in the planning stages and they came up with a custom grind for my combo.

David

http://www.nuibe.com/elco/main.html

This one comes to mind he's a member of TC.

Hey Pat,
The elky rolled out of the factory weighing in around 3100 in '67. I have removed the heavy tail gate and inner fenders (-70lbs). The car has no power brakes, power steering, or AC. This keeps is pretty light. It car is all steel.
Danny

Originally posted by 77 cruiser:
http://www.nuibe.com/elco/main.html

This one comes to mind he's a member of TC. Hey, I know that guy! ;) The car has gone a fastest of 11.39 @ 117 MPH with some missing body panels (hood and tailgate). It regularly ran 11.5 @ 115 with all body panels. The motor is actually a standard 4.00" bore so it is more like 377 ci. I run naturally aspirated on pump gas and have small 170cc Edelbrock heads. More details of my combo are on the website.

I e-mailed Greg awaiting a response.....

Our Malibu hasn't been in this configuration for several years, but ran mid-11s @ 116+ (best (11.427/117.79) with the following:
- 3550#
- 383 sbc
- Summit modified Dart II heads
- Reed hydraulic cam (254/250, .560/.506, 112 lsa)
- 10.8 cr
- Victor Jr.
- Edelbrock 750
- 1 3/4" headers
- Richmond 5 speed
- 4.56 gears
- Goodyear 29 x 10 slicks

Originally posted by Junkyard Dawg:
I e-mailed Greg awaiting a response..... When? I don't see it...

Sorry I mean to say I emailed Eric68.......

My Elcamino ran 11.8@111mph with a 385 sb 3685# with me in it all motor mid 10's with a 150 shot
I have since changed cam intake and carb to try to get into the 10.'s on motor w/ pump gas

Mike

My Chevelle ran 12.57 with a 350, ported camel humps,280 solid roller cam, 4.10 gears 3000 converter, on drag radials. no nos. I drove it daily on pump gas. So a 383 should be no problem in the 12s even in a heavy car. My race wt. with that engine was 3770 lbs.

400hp (350rwhp) should get into the 12's easy, 550hp (450rwhp) should get you into the 11's with a 3800# car/driver combo.

400hp is easy with a 383, 550hp is alot tougher for a "streetable" 383 but can be done.

What engines (besides a 454 and larger) can make 450-550 hp with some minor mods and still run on 93?

Junkyard,

Unfortunately, it is going to take a decent head to make 450-550 HP on an SBC. That may be a stock ported or an aftermarket head. Moreso than that, to run mid 11's is going to take a well thought out and equipped car/package.

My old 10.31:1 - 383 SBC ran mid to low 11's at 3600 lbs on 93 octane pump gas. It also had a decent set of AFR heads, solid roller, etc. Not to mention aftermarket suspension components, ATI converter, and 4.56 gears.

Actually if I decided to run with a 383 I would look into some AFR's and probably a roller cam with some headers and a true dual exaust with Ultraflows too. In fact I had planned on investing the most into the top end as compared to the rest of the engine. I also plan to run a 3000 stall converter with a TH350/4.10 rear out back.

Jason what was your engines combo?

We ran a 383 with AFR 220 heads for a while. The problem is... in order to take advantage of the AFR heads, we had to get more lift and duration, which in turn required more compression. It ended up at 11.50:1 and we weren't willing to take a chance with pump gas at the track. But, it ran 10.70s/126 @ 3500#.

danny from mc allen tx i would bet 5 that you would be in the 11s if you switched to 1 5/8 headers dont believe it, try it my 66 slow 2.5 tenths in the 1/8 th mile when i put the 1 3/4 headers on switched back and the car went back to running 7. 20s .66 chevelle ,inside gutted ,glass hood and front bumper,488 12 bolt,glide 383,ported 186 heads, flat top cast pistons 5.56 rods,elgin solid 557 533 lift intake 264 256 exaust at 50 thoustants ,victor intake, 650 double pumper 15/8 headers, 28x10s slicks 4000 stall cheep motor but ran good 7.40s the best in the 1/8th sold the motor to a buddy put in a camaro and ran 7.teens consitant only change was intake team g and 750 dp 8 inch stall and im sure more gear probable 5 14s not sure

:cool:

my 71 chevelle ran 10.50 @ 128 on 93 octane
383, turbo 400, 373 rear, a/c, p/s, p/b, 295 d/r's on the rear
full interior, 3815 lbs w/me-drive anywhere
oh, i forgot, it had a d1b procharger with
an intercooler-i think that helped a little(lol)

Junkyard, you may want to do a search for a screen name of "sheetmetal". His 383 is all pump gas all the time, hydro roller, full exhaust, 3600lbs and has run 10.80's@122 in good air on motor only. This car is VERY docile and I would have no qualms driving it to California and back.

Hey Junkyard Dawg,
You are probably right! I debated using 1 3/4" headers, but my neighbor was running 10's with his LS1 using 1 3/4" headers. I just had to try them, LOL! Next time around I will try the 1 5/8" headers. Does anyone know anything about those step headers....they start out at 1 5/8" near the engine and step up to 1 3/4" near the collector?

Danny

Actually that was my twin brother "Dog" that said that. :cool:

Hhhmm...so are we saying running a set of 1 5/8 headers is better for this application as opposed to a set of 1 3/4 headers?

John I'd be very interested in hearing this guy's combo. If I could put my car into the 10's on an all motor 383 that was streetable I'd have the biggest grin on my face that no doctor could ever remove.

So if I switched from 1-3/4" headers to 1-5/8" headers could I expect to pick up 2.5 tenths too?

My current best is an 11.31 @ 122 MPH with a little tire spin.

Honestly I think the 1-3/4" headers are better for someone shooting for 11's with a 383.

eric its possible you wont know till you try it .when i did it i was running a 406 and running 7 teens to 720s in the heat of summer .i bought the headers from a buddy who was running a camaro with a 350 running 680s .they were brand new hooker supper comps he said he was selling them because he slowed up 3 tenths when he put them on.never the less i thought he was full of it.i put them on and went to trac car ran 740s all night so as soon as possible i change back .went back to track and the car was right back to 20s and teens.my personel feelings on this is the heavery the car the more torke you need to get moving so thats where the 1 5/8s headers come in.i also dont wind it to the limit whitch may make a difference.the combo was 406 sportman heads ,victor intake ,750 dp holley ,flat top pistons ,elgin cam 556 533 lift 264 256 dur at 50 .the heads were angle milled to get compression up.i am running the 1/8th mile but 2.5 tenths would be hard to make up in the 1/4 ,oh yea glide with 488 12 bolt.i wouldnt run out and buy a set of headers to try it but if i had a set to try i would.you may be surprised.now this is for 200 cc heads and below my 210 arfs wont work with 1 5/8 headers.sorry to be so long

Originally posted by Eric68:
Honestly I think the 1-3/4" headers are better for someone shooting for 11's with a 383. I'm not so sure.

Well, I should qualify this by saying I have not tried a larger header myself but would certainly like to if I could do it without buying a new set for $300. smile.gif

But I'm currently running 1-5/8" headers on my 406 and doing okay. I think at this point it makes more sense for me to go to a bigger tube b/c I've also recently left the dual plane RPM for a Vic Jr. But for a 383 trying to run 11-12 ETs I would think the smaller tubes would help build the lower end torque you'd like to have to get out of the hole.

Back to the original question...a 70-72 Chevelle weighs a lot more than my car. Still, I would think a decent set of heads with a nice hydraulic roller cam (I ran the Comp retro XR288HR last year: Cam Specs (http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=12-433-8)
and whatever compression you can get away with (with said cam I ran 10.36:1 to run pump gas), matched to a decent converter and rear gear I think 12s should be no problem.

Personally, I love the roller cams. I've run 3 different cams in my current engine and when I swapped from a solid flat tappet (CC 294S) to the aforementioned hydraulic roller it was worth a quarter second in ET.

I'm not trying to sound like a know-it-all. There are enough of those scattered around the internet. Just trying to share my own personal thoughts. If 12s NA is your goal it should definitely be acheivable without having to resort to a power adder.

I truly believe that whether you run 1-5/8 or 1-3/4 headers it won't make a huge difference. But I still cast my vote in favor of the smaller headers.

Good luck.
-gw

Originally posted by gwarren:
I truly believe that whether you run 1-5/8 or 1-3/4 headers it won't make a huge difference. But I still cast my vote in favor of the smaller headers.

Good luck.
-gw [/QB]Exactly. I don't think there will be a huge difference either (and IMO anything over a tenth is huge) unless there is something wrong with one of the two sets of headers like a port mismatch . . .

The higher the RPM band the engine will work in, the better the 1-3/4" headers will work, the more of a grunt motor the engine is the better the smaller tubes will work.

Tube length is important too. Shorter tubes move the effective power band up and make the power band narrower, longer tubes will make a lower, wider power band.

And remember when referring to tube diameter we are talking OD. The ID is what the engine sees.

-- a 1-5/8" header made of 16 gauge tubing actually only has an ID of 1.505" or just over 1-1/2"

-- a 1-3/4" header made of the same 16 gauge tubing is only 1.630" or just over 1-5/8"

JYD-on the car that picked up going to the 1.625" headers, what was the race weight?

Header size is a function of hp not engine size or rpm. That statement is obvious when you stop to think about it. Power is a function of how much fuel you burn. The more fuel you burn, the more air you have to pump thru the engine. The more air you pump, the bigger the exhaust has to be to accommodate it.

Now, 400 hp will get a 3800# car into the mid-12s and 1 5/8" pipes will work just fine at that power level. The same motor with the same headers will push a 3000# car into the mid-11s. However, getting a 3800# car into the mid-11s will take about 500 hp and that motor will need 1 3/4" pipes.

The point here is that just because you know someone who got improved performance by going to a smaller (or bigger) header doesn't mean that the same change will work for you. (How much power are you making?)

There are 2 guys with c-4 and 434 CID in them. The one guy was running 10.30's on motor with his 1-5/8 headers, he switched to 1-3/4 headers and picked up .10. Not worth the $600 for the coated headers. These are roller cammed 12-1 brodix M2 headed big sbc.Both carts weigh 3300 lbs,700r-4 trans ( one 4400 non lock up) the other 3800 lock up. The faster car runs 3.07 gears and 26" tall tires, the other 373 and 28" tall tires.

On a N/A application i would stick to the 1-5/8. I know... i have 1-3/4, but i got them for $100, otherwise i would go 1-5/8 my self

Originally posted by marooned:
:cool: ive been waiting for you to make a comment here.
smile.gif

john i have never weigh the car its a 66 malibu hardtop no lexan glass hood and bumper up front its ladder bared with coil springs and gutted inside with drag seats and carpet.my guess would be 3100 to3200

JYD- 7.20's at 3150 tells me the motor is around 430hp. A 1.625" primary tube would be appropriate for that power. I like 1.625" upto about 475hp and 1.75" upto 600hp and 1.875 up to 700 or so. Of course, this is just a rule of thumb I follow for primary tube size. As has been suggested, there are other important factors to consider such as primary tube length, collector size/length, etc..

Mike- a tenth gain at the low 10sec level is significant IMO as Eric also stated. Whether $600 is worth it or not depends on the individual.

One things for sure, going too small on the header size won't hurt nearly as bad as going too big.

I need to ask where do step headers fit into the equationI have been looking at 1.625 - 1.75 step to a 3.5 collector how would they work for a 500+hp sbc motor

Mike

Mike - that step header would work fine.