1979 Chevy Camaro Z-28 - 12.60@112 - CI: 402

[MagicRatt]

Owner Information

• Home Town: Southampton, Pa.
• Primary Use: Index racing
• Estimated Investment: @7500 bucks
• % of Wrenching by Owner: 95%

Basic Car Information

• Year: 1979
• Make: Chevy
• Model: Camaro Z-28
• Weight: 3690

Proven Performance Information

• Best ET/MPH: 12.60@112
• Best 60´: 1.81
• Performance Rating (5 is best): 3
• Street Manners Rating (5 is best): 2

Gearhead Information

• Engine CI: 402
• Bore: 4.125
• Stroke: 3.76
• Block: cast iron 2 bolt main
• Heads: closed chamber square port
• Ported? (With flow numbers): N/A
• Crank: GM steel
• Rods: Scat
• Pistons & Rings: Pro-True
• Cam & Lifters: Crane solid with .570/.590 lift 290 dur. w/ 110 lsa
• Intake: Weiand X-celerator
• Distributor/Ignition: Mallory Uni-lite w/ hyfire 4 box
• Headers: Hooker Comps w/ 2 inch tubes and 3.5 collector
• Tran & Brake: Muncie M-22
• Converter: N/A
• Rear End Gear: Nine inch w/ 5.00 gear
• Tire Size: 28x10.5 ET street
• HP/TQ Number: no dyno time
• Power Adder: none
• Compression & Fuel Used: 12 to1 comp/ Sunoco race gas
• Chassis Tricks: trick springs, adjustable shocks, cal-tracs
• Carb: 850 Holley

Proof

• http://content.godragracing.com/vids/atcofinal/BussettiIndexQual.wmv

Special Notes

• It don't work well. Seems to be lacking some low end torque based on 1/8 mile times.

Advice Needed

• This car was just built but is not yet finished. We only have about 20 runs on her so far. The 2006 season should bring better times but any observations or suggestions would be helpful.
  Rich

[93COUPE]

cool video. the thing launches great then falls flat instantly. is it possible to get the rpms up on the launch without spinning the tires? i know this sounds dumb but try it in second gear. at least it is a four speed. you gotta love slamming them gears. makes you feel like you did something. no offense to the auto guys.
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being broke sucks.

[80'427]

What kinda clutch? How heavy is you flywheel?

[MagicRatt]

One of things that killed me was switching the box to the M-22 unit. It is a stronger box but the first gear ratio is terrible at 2.20 to 1. My old M-20 box was a little better on the launch because of the 2.54 first gear, but the box would only last about 20-25 passes before it greneded. The "band-aid" fix was to change the rear gear from 4.10 to 5.00. The sixty foots got a little better (1.98-2.10 to a 1.81-1.88)but the 1/8 mile times are still tragic at 8.24@ 88 mph.
I launch the car around 4500-4800 rpms. Any higher and it becomes a pedal fest then a killer bog. Last season was also the first year I used ET streets. I raced on BFG drag radials for years. The flywheel is a 30 lb. Hayes unit with a centerforce dual friction clutch. I've chatted with my engine builder and without going to a chassis dyno we can only guess that the lack of low end torque is the culprit.
Right now the weather has me tied up since the car sits outside and is halfway disassembled. Have to wait until spring to finish the job.
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If it ain't broke, don't fix it....

[80'427]

I am not, repeat not a expert on manuals and clutches but I have read a bit and do have some ideas for you. Some of the reason you have a bog after the clutch release could be your clutch is hitting too hard and pulling your engine too low in the rpm range. This will do just as you say hit hard and bog out of the hole. I would suggest you vary your release speed. Instead of a dump try a fast release which will allow a enough slip to get your car moving but not so much of a load to bog your motor. In talking with other high end manual drivers, alot of them told me that in most cases when they went to a adjustable clutch they could control the this amount of hook and actual get a better run though there 60' may be a bit lower. Just some ideas. I have the same clutch as you and haven't had a chance to launch it hard and see but I intend on doing a bit more slipping than dumping, plus it may save my st-10 by lowering the shock load. Liberty transmisson told me to talk to Ram Clutches about what clutch I should run.

[MagicRatt]

I have seriously thought about going to an adjustable style of clutch at some point. I dread the thought of switching to an automatic so I will try anything once, maybe twice. Before I spend any money on anything I am going to chassis dyno this thing to make sure I know what I am going after. My engine builder told me when we drew the plans that these engine components I was using would be peaky. I told him I was hoping that running the stick shift would help some of those "peaky" issues out some. Plus, those parts we used already existed in my inventory and since I was on a very limited budget, it helped keep the cost down. We both believe that switching to oval port heads and 1 7/8 headers would improve low rpm torque and thus improve 1/8 mile times and overall ET. Once again, not in the budget so far this year. I seem to spend too much time searching for the "happy medium" rather than cutting lights and hitting gears. That's what I hope to change this season.
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If it ain't broke, don't fix it....

[80'427]

I have a friend with a very similariy built 396 (except open recs) He said before it was very lasy till about 4500-5000. He then switched to closed ovals and the bottom end was great and pulled like a freght train. He said it may have had lost top end but it ran so much better he left it and even got it to run 12.20s with a auto and 4.11s (in a chevelle). He now has open ovals (to run pump gas) and it has lost a bit of bottom end but is still very quick and has boat loads of torque. To bad you are in PA I bet he would sell the closed ovals pretty reasonably (already set up for 2.19s and 1.88s), then you could at least see if they helped.

[Brian Raymond]

I think your problemb is in your heads. You have a small bore rec. port and a closed chamber head kinda the worst of all things to be honest. You leave the line great because you are in the right RPM to take some advantage of the rec. ports but as soon as you get of the line your RPM goes down and you "BOG". now all you are try to do is fill them big ports instead of filling cylinders. I bet it doesn't do to bad when you get it back up int the RPM again. I would personally go with an open chamber oval port head on this combo. Hope it helps. Have a great Day

Brian

[MagicRatt]

I knew when I was building this piece that it was going to be a little sluggish but I didn't think it would be a total dog. I've run this combination before in my old ride using the stock L-78 cam. It was kinda the same story up to the 1/8 mile but after that the car was a rocket ship. Once again, the parts I used were what I had laying around in the garage. Sometimes you hit a home run and sometimes you don't. Just have to go back and do some re-figgerin'out.......

Rich
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If it ain't broke, don't fix it....

[Brian Raymond]

I hear ya. I am running a lot of miss matched stuff I have laying around as well. I would rather have it run not as well as aposed to not running at all waiting on money for parts. LOL

[MagicRatt]

Updated times.......We finally made some progress with this beast and cut a 12.36@112.9 after switching to a spool and re-jetted the carb.....alot!!
_________________
If it ain't broke, don't fix it....