Last night I made some quick passes with the G-Tech to see if there was an appreciable difference after installing the 3.73 gears and getting the 700R4 working properly. These results are far from being statistically significant but here they are none the less.
My best 0-60 with the 3.08 gears was 4.91 seconds.
Last night, my first 0-60 attempt was 5.1 seconds. After a couple of tries, I finally pulled a 4.91. I stretched it out through the 1/4 mile and it showed 13.67 @ 104 mph. (yes, I know that the mph reading is higher than would be indicated at the drag strip)
Not much improvement yet. I'm sure that I could better it with some launch practice.
Time to start tweakin' the Q-Jet. After installing this 383, I simply pulled the ol' grungy Q-Jet off of the old engine and bolted it to this one. It is working suprisingly well but surely it is a little lean.

This car was built to be a "Street Machine / Cruiser" but it would be nice if I could get consistant 4.5 second 0-60's and 13.0 second 1/4 mile times.

 

Thanks for sharing. :yesnod: It's alway good to here results on mods.

 

If I'm understanding correct after the install of 3.73 gears you ran the same, that surprises me. Although it sounds like your car runs pretty fast.

 

With that setup you should have no problem getting what you want out of it. :cool: :cool: :cool: :cool: :cool: :cool: :flag

 

You need to get some forum Q-Jet tweaker to tell you the correct rod/jet combo you need. Q-jets are a very nice carb and the small primaries really help off idle throttle responce. I just have not worked on one in 15 - 20 years. Stock HEI ignitions are also a great item especially when you install a better coil. HEI is not HP limited per say. It's rpm limited to mid 6000's where it starts to get distortion if you were watching it on a O-scope screen. So in reality nobody with any kind of Hydro - cam is going to over rpm an HEI.

I'm going to make a bold statement about carbs and it could be disputed.

A given carb will deliver the the same A/F ratio no matter what the cubic inches (327 sbc - 496 BBC) of the motor it's placed on.

So just because you went up in cubes doesn't automatically mean that you went lean. Motor variables like big single plane intakes, radical cam durations, C/R, and free flowing exhaust. alter the A/F needs. Over the years walking around the pits or talking in the staging lanes about jetting. I'll bet that I can tell within a jet size or two of the pri & seconds of any 750 double pumper no matter what the displacement from 327 to 496 ci. Just by looking under the hood and asking a couple of questions. Even the guys with the Oxygen sensors and AF meters. Of course this only applies to people that know what they are talking about on their street/race cars.

Some day I'd just like to play with a G-Tech


[Modified by gkull, 3:02 PM 5/31/2002]

 

I would only add that it flows the same once the peak cfm for that carb is reached. At that point no more air can be drawn in so there is no way that you could change the a/f ratio. If you put a 1000cfm carb on the 327 it might not reach the peak cfm at wot throttle and max rpm but the 496 big block could pull the full 1000cfm so I guess I am saying you are wrong after all. Of course I am assuming th 327 can't pull the full 1000 cfm but that could be wrong and my whole theory is shot!

 

Fevre - I'm talking about common sense carb air fuel ratios. 600 cfm - 850 cfm. I need some poopie from everybody tonight! :yesnod: I'm thinking right now of going and getting Monty's favorite beer. It's not really worth drinking beer unless it come out of a green bottle! Hieniken :cheers:

Heres just and example: I used an Edelbrock 750 carb for ten years on my 355 ci. Right after buying it I noticed that the choices of AF ratios in the graphs in the owners manual were way spread out. You have to be a little more precise than 4 or 8% jumps that edelbrock tuning book. So I figured out the surface area of flow for all the diameter of jets I would be using. Then I figured out the blockage of the area of the rods. So then you pluggin the jet and rods from the book and you can see what they are doing

Jet hole area minus rod area equals the total flow area.

So with a little math you can make very tiny changes to the AF ratio. Then I took my car to the rear wheel dyno and a exhaust sniffer and dialed in my 750. Then 6 months later a guy at work came up to me and said that his performance model 750 Edel was way to rich out of the box here at 4700 feet. So even though he had a moded 472 ci BBC his jetting was exactly the same as mine and it ran like a champ with simular plug coloring.


[Modified by gkull, 12:44 AM 6/1/2002]

 

Not bad quarter times, keep at it. :D

 

gkull is right. take a stock qjet off a 350 and put it on a 434sb and WOT will be the same a/f. Years ago i put a 650dp off a 350 on my 283, worked fine. I have no idea why Miker is fooling with the carb; could be old and in need of a rebuild? Or sombody swapped rods and he knows it is wrong?

I gave him my link for O2 tuning and he did not seem interested in that; that is where the gain will come.


[Modified by drives61, 7:25 AM 6/2/2002]

 

Yup, the carb is old and in need of a rebuild regardless of it's jetting.
I also agree with gkull's statement "A given carb will deliver the the same A/F ratio no matter what the cubic inches (327 sbc - 496 BBC) of the motor it's placed on." but like he also said, "Motor variables like big single plane intakes, radical cam durations, C/R, and free flowing exhaust. alter the A/F needs.
My engine was basically a stock L-48. Now I'm running headers, longer cam duration, improved heads, increased compression, etc. I'd say that "fooling with the carb" is not an unreasonable thing to do at this time.
http://forums.corvetteforum.com/zerothread?id=311497
Sorry I didn't comment on the link you provided. I guess I was trying to reply to too many at once. I am very interested in tuning with an O2 meter. I already have that particular link saved along with a few others related to tuning w/O2 sensor. If money were no object, I would have sooo many cool tools in my shop that you couldn't park a damn car in there. :lol:
I already have one of the newer "heated" type O2 sensors, just need to purchase the meter.