Thread: Cam and vacuum chev 400

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My SBC 400-- 40 over, has a 292/512 crane cam in it supposedley. I bought it from an engine builder in Indy IN. I have had some problems w/ it but have finally got it running strong w/ some help from this site. I don't know that much about cams except how they operate (lifting the lifters and pushrods and opening and closing of the valves). This cam I have in the engine I have never been able to locate in any Summit or Jegs catalog in an SBC profile. Is this a normal grind? The car runs pretty strong now after tuning w/ a vac gauge. I pull 22" manifold vacuum at idle which is 1000 RPM w/ a steady needle. Timing is set at 15 degrees initial. I'm guessing this is good right? The car has somewhat of a lopey idle.
My question is why can't I find that profile for a SBC in a catalog? Is this an aggresive cam? I am currently using a edelbrock eps intake w/ the setup. The intake is setup for idle to 5500 RPM. Also using a Holley 4160 750 cfm vac sec carb. What would be a better street cam w/ maybe a little more rougher idle and some more power that I could use w/ this intake.

Anyone.....I know someone has some insight. You guys have helped me through some crappy times.

Are you running a stahl convertor

Any cam that can pull 22" is very mild. A factory cam pulled only 20" at 600 or 700 rpm. What I recommend you do is turn down your idle until you get about 20". You may also have to retard the timing slightly when you do this, but it should help keep you from burning up so much fuel when you're sitting at a stop light. If you're pulling around 20 inches and it's idling smooth, you've got it right. I'm guessing 800 rpm at 12 to 15 degrees is just where your cam wants to be.

Yes I am running a 2200 to 2500 stall. Maybe my motor does need some more cam. I thought a 292/512 was a good profile for a street car. I mean it sounds nice sitting there idling. It just seems to idle best at 1000rpm w/ very minimal vibration. this engine is suppose to be 425hp... oh and the vacuum reading was taken right after a spirited run, if that matters.
The only profile I have found under that was for a Ford. The engine shop specalizes in ford motors...maybe I shouldn't have bought it from those clowns.

292 duration cam pulling 22 hg of vacuum. hmmm
are you looking into a new cam?

400's generally pull more vacuum, but I don't think 22 inches is possible with a 292 cam. One of those cams is more likely to pull 8-10 inches at 1000 rpm. Comp sells a 292 duration cam and warns of rough idle and limited street use and recommends a minimum stall of 3000 rpm.

With the 2200/2500 stall after market heads comp makes xteme
energy 284 stick. Any true 290 or larger would have a very noticeable idle and would be to big for that stall!! JMO!!!!

Thanks guys for the replies, yeah I guess I might be looking in to a new cam...I mean the car gets up and goes but it doesn't put me back in the seat like I thought it would. I think the stock 2.73
rear gears have something to do with that though.I plan on switching to 3.42's. I don't think this is a true 292/512 crane cam. I know the only way to really tell is to degree it but I minus well buy I cam I know will work w/ my setup, and I'll know exactly what I'm getting. I wish I would have built this motor myself. Anyone got any suggestions.????????

Thanks Denny for your post....Maybe this will help my situation. I just found my cam card but I don't really know how to read it. My scanner is broke so I'll write down the info:

Grind #10044

VALVE SETTING: INTAKE HYD EXHAUST
------------------------------------------------------------------------------------
INTAKE @ CAM .320 @VALVE .480 `

ROCKER ARM RATIO
1.75

LIFT:EXHAUST @CAM .320 @VALVE .480

ALL LIFTS BASED ON ZERO LASH AND THERRETICAL ROCKER ARM RATIO
-----------------------------------------------------------------------------------
CAM TIM.
@.005 LIFT

OPENS........... INTAKE 37 BTDC
CLOSES........... 75 ABDC
ADV DURATION. 292

OPENS............. EXHAUST 75 BBDC
CLOSES..............37 ATDC
ADV DURATION... 292
------------------------------------------------------------------------------------
CAM TIMING
@.050

OPENS.............INTAKE 8 BTDC
CLOSES...........42 ABDC
MAX LIFT..........107 ATDC
DURATION........230

OPENS..............EXHAUST 46BBDC
CLOSES............4 ATDC
MAX LIFT...........111 BTDC
DURATION.........230
------------------------------------------------------------------------------------

I have no idea how to read this. I was just told that the cam was a 292/512 from the builder. Does this add up? I also noticed that the rocker arm ratio is 1.75? I thought racker ration for SBC is 1.5 or 1.6

Thanks for the input....is my cam more aggresive than a 292/512? I really can't believe what the engine builder says is in there. Also what about that rocker arm ratio "1.75" that it states on the card...I'm using a 1.5 ratio crane aluminum roller rocker setup. does this matter? I really appreciate you taking the time to write as I have had many problems w/ this engine and the builder.

That's a big 10-4 thanks again for all your help. Your one of the reasons this site is the best around.