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Author Topic:   vacuum help
vinyl image
Member
posted June 03, 2002 08:51 PM
hey guys great forum, we have a 17 inch vacuum rule here in savannah, the guys running up front are getting 17 or more when checked. I know for a fact they are not stock, and need help in beefing up a stock 350 and still pull 17. thanks


BayouGent
Member
posted June 04, 2002 01:25 AM
How much camshaft, timing, and good tuning will determine how much vacuum you will pull with any engine. What are the rules in regards to cylinder heads, valve sizes, induction, and pistons (flat top?) you can run in the class you're in at your track? What is the cubic inch limit and can you have stroked or destroked engines? Do they limit you to only hydraulic or can you run solid or roller cams? Most cam manufacturers have tech lines that have qualified personel to get you the right cam that will make the most power while maintaining the vacuum you need. There's also a guy on this forum from Hendren Racing Engines who is very knowledgable as well. I'm not sure if he sells cams or just builds the engines, but I'm guessing he'll probably want some of the same info I asked for in order to help you make more power while pulling 17" of vacuum. If the rest of your engine rules aren't too strict, you can make alot more power than you might think with that vacuum rule. Just list all of the info you can and the answers will likely be plentiful.


smayo964
Member
posted June 04, 2002 06:44 AM
Hey Vinyl. Here in Columbus MS we have to run 17lbs if you are running a 4-brl carb. I ran a Comp Cam, hyd XE274H, coupled with a set of fast bleed lifters and pulled the 17lbs at 1000rpm. I had all cast/stock 350 with 305 heads, headers, and Holley 600 with vac/secondary carb. The cam is rated up to 6K, but kept pulling up to 6,800rpm well (my max). The cam has an extremely strong midrange which you could feel in my 3,300lb car. Hope that helps.


vinyl image
Member
posted June 04, 2002 05:43 PM
thanks guys, the rules are basic stock motor that came in the car including head #'s, we must run auto trans, and all 350 cars must weigh 3600 pounds and run 308 gear. we have a claimer rule, the track usually checks vacuum head #'s maybe a valve but not often.
I have not seen a cam pulled in 2 years. this has got to be where to go. I'm running of a 5/8 mile track at 5700 rpm. thanks for the help.


smayo964
Member
posted June 05, 2002 07:09 AM
Hey Vinyl. If you are only pulling 5700, you might want to really consider that Comp Cam. They also have one just a little smaller with typical power bands. I'm actually going to use mine in my mod with 1.6 rockers for more lift. My camaro was also 350, auto trans, but I ran a .273 with my t350 in 1st on a .3 mile fast high banked track. Go to Competitioncams web site and look at the "Extreme" series cams for V8. Even for a claimer motor, this cam was somewhere around $100 or less. Good luck at the track.


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