My apologies as this is kinda off topic since the vehicle in question is a 72' Riviera GS. The Riv was not starting easily and running kinda rough. So far I've made a lot of improvements by replacing the battery wires(ground wire was ancient), advanced the timing(improved throttle response and a little smoother), and I opened the points dwell a touch. It also has a minor exhaust leak. All my favorite tuning stuff(timing light, tach and dwell, etc.) is in the trunk of the Rocket which is still two hours south so I'm afraid to mess with the points further since I don't even have a feeler gage with me. I suspect they are bad and the cap and rotor could stand to be replaced as well. The plugs look good, almost a little lean(light brown/tan color). I'm also thinking Pertronix instead of points. All the smog crap appears to be bypassed and it has an Edelbrock carb(weber/carter afb clone, cfm unknown) in place of the stock Q-jet. My questions are; should I expect the 455 to become a tire-melting beast after just a proper tune? And what is optimal carburetor cfm for a stock cam 455 Gran Sport?
I would play with the centrifugal advance curve a bit, as it's probably fairly sluggish from GM. Also try a little more initial advance....see what it likes. You might get surprised by the improved throttle response. So far as a carb, my personal preference for that car, given the stock components, would be either a 750 VS Holley, properly tuned, & a good adapter, blended to the intake as needed, or a good Q-Jet...others might differ. The E-brock probably isn't killing anything, if it's set up well.
If that's a Stage 1 you can absolutly expect it to be a tire eater. That is one of the many cars I drove to High School and I liked it even more than the Vette. Of course that may have had more to do with the back seat than anything else Despite it's girth, that puppy will move with a Stabe 1 in it. With the garden veriety 455 you should expect only slightly less smoke and shreaded tire billowing from your rear fenders. You're on the right track with the ignition replacement though. In this day there is no reason for anybody to have to mess with points. I like the Pertronix unit because it goes well with a traditional build but, in a '72 Riviera I don't see why not just stick an HEI in and be done with it. They're cheap and dependable and you can get parts for them anywhere. Besides, under that massive 6 foot hood it would hardly be noticable. I have no idea about the Edelbrock carb you mentioned but, I am all together in love with the much meligned and misunderdtood Q-Jet. Jim Bell himself told dad it was the best carb in the world. I guess I'm prejudiced toward it because it's what I grew up with and am most familiar with. The Q-Jet is supper easy to hop up. There are plenty of other's on the board much more qualified than I to give advice on tuning though. Good luck with a great car.
ditch the edelbrock and get a properly built and tuned q-jet on there. i have a 10.7:1 461 olds that will turn tires into long black strips of powdered rubber and get 14 mpg around town. another vote for the HEI swap...cheap, easy and will work much better.
Should go with a 800cfm quadrajet. The 455 is a tourqe monster. Do a search on power timing your 455 on www.v8buick.com this should waken it up quite a bit. Here is the direct link http://www.v8buick.com/showthread.php?t=63475&highlight=Power+Timing
Get a timing light on there when the opportunity presents itself. See how much the timing moves around when you raise and lower the rpm a little. Most of the 455's I've played with needed the timing chain replaced. Ditto on putting a Q-Jet back on it. Get Doug Roe's book on building Q-jets. Makes a huge difference.
Hah ! You beat me to it. V8Buick is the best site on the `net for anything related to Buick Muscle. A well-tuned, bone stock Buick 455 will absolutely fry your tires into smoldering piles of rubber. 800 Q-Jet is best choice. Get a good used HEI. (`74-76 455 Buick only). There should be at least a couple in the V8 Buick classifieds. They usually go for $50-75.
Thanks for the input fellas! Those links rule! I'm definitely looking for a Q-jet now as I've discovered the Edelbrock carb is 600cfm which belongs on a small block. I'm also thinking the vacuum secondaries will provide better acceleration as this car weighs 4400+ lbs.
While we're at it anyone have any experience with aftermarket intakes for the big nailhead? The stocker appears to have flow unfriendly angles and a way low profile. Ive seen Offy and Edelbrock ones for 250-300 bucks.
The best street intake IMO for a big block 455 Buick (a 455 is not a nailhead by the way) is a vintage Edelbrock B4B... NOT the newer version. It's a 2 plane manifold so it's perfect on the street and I run 12's with a pretty stock 455 Stage 1 in my Buick. Sometimes these turn up on ebay.
I thought they were all nailheads. I guess I need a little Buick schoolin', which is why I'm here. Dig the hei idea. GSX, you're the second person to tell me that, why do the new b4b's suck?
70-72 GS hoods have ram air scoops in the hood that match up with the foam scoops in the stock air cleaner. That ram air has no effect except for ram rain Most guys just use and open air cleaner instead for better performance. The old style B4B gives a performance gain over the heavy stock manifold but the stock air cleaner setup does not match up to the scoop holes in the hood with the old style B4B installed. Edelbrock came out with a newer version where those holes do match because they moved the position of the carb mount but because of that, it does not offer the performance increase that the old version did. It is a lot lighter than a stock manifold, so that is a benefit. Interesting fact: the 455 was a new lighter casting block and with an aluminum intake manifold installed, your 455 is lighter than a small block Chevy motor. I hope that info is of help. Paul
One more thing... if your Edelbrock is an older version B4B you could probably sell it on ebay for $250!
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