73-454

The vacuum reading is 11 at idle in "N" and at 5 in "D" Power brakes don't work very well.


Camshaft Specification Table
Part Number 11-213-3
Engine 1965-present Chevrolet
396ci-454ci
8cyl.
Grind Number CB 292H-10
Description

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Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.55 0.55
Duration At 0.006 Tappet Lift 292 292

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Valve Timing At 0.006
Open Close
Intake 40 72
Exhaust 80 32

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These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 244 244
Lobe Lift 0.3235 0.3235
Lobe Separation 110

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Recommended Valve Springs 924-16

Gordonm

Mine is very similar but mine is in a 350. 248 duration at .050 and a .525 lift. The cam is not much good below 3000 rpm but really takes off from 3500 to 6500+ rpm. Idle vacuum is about 8" at 850 rpm in neutral.

gerry72

I think you have other problems there. While it would be better to have a wider lsa with that duration, you should be able to pull around 12 to 14" in park and 10 to 11" in drive with a 454. What is your initial advance set at? You can really improve your idle vacuum by using more initial and less centrifugal advance. Check your carb adjustment. How sensitive is the engine (rpm and vacuum) to the mixture screws? How particular was your lifter pre-load adjustment? I hate to even suggest a vacuum leak, but that's also a possibility. Another dreaded possibility is that the cam is retarded.

Sigforty

I plan on using this cam in the Big block I am building for my car. The cam is a nice cam you just need 10:1 compression to run it effectively. It has enough overlap to run a bit higher compression on iron heads if needed. I talked to my machinist and he told with this cam and a mild setup on a 454 I should expect close to 500 horse. My friend ran the same cam in is 68 camaro and runs in the 12's when stuff does not break on his car. The last time he went to the track he ran a 13 something and spun the balancer and broke a motor mount on the same pass.

Mark B.

gkull

Who ever built your motor didn't understand much about matched components. You could use crutches to prop it up. Belt driven power assisted brakes and a higher stall converter. Here is Comp Cams blurb on those style cams.

280H Magnum™ is best for the more serious street machines. This cam has a definite rough idle and will sometimes affect power accessories. It can be driven extensively on the street or raced on the weekends. The 280H needs an aftermarket torque converter, intake manifolds and headers.

286H Magnum™ is a design to fill in the gap between the 280H and 292H. Designed for serious street machines and bracket racers. With a rough idle and lower vacuum signal, this is not an average street cam. At least a 2500 RPM converter must be used, but a 3000 is recommended.

292H Magnum™ is for the serious “Street/Strip” type car. An aftermarket torque converter should be used as well as headers, intake and increased compression. The 292H has a radical rough idle.


When you get down to the actual .050 specs on the 292 cam it's not really anything special. Low lift and 244/244 duration. It's for the guy that want's a bad sounding car that doesn't run worth a poopie. Unless you have 12.5 pistons and open big headers and your mileage is measured a 1/4 mile at a time.

mountainmotor

In his newest topic he says it was built with 8.5 compression :nono:
Still don't know what intake, carb and gears he has or the rear gear ratio or if it has a stock stall.

gerry72

Well then, forget it. There's no way that you'll ever get that cam to work with that low of a compression ratio. The low compression ratio is the reason behind the low vacuum. Advancing the cam would help, but maybe not enough.

Jason Staley

I agree about the compression, it needs to be higher - probably 9.5 - 10.0 to really work good. I have an Oldsmobile 455 (bored .040 over) with a .541/.548 lift & 246/257 duration at .050" lift. It's compression level is about 10:1 and it works great - produces lots of power. Don't really know about the vacuum - haven't checked it for a while mainly because I don't have any vacuum powered accessories. Manual all the way. :D

Another thing you can do concerning vacuum, is to use Total Seal's Gapless Rings on your pistons. They claim a 5-6 inch increase in vacuum due to better sealing. They also are suppose to add a significant amount of HP too. All for about $200. If you go back into the engine, I would seriously think about adding this to your list. Specially, with all the vacuum junk that is on our vettes. :lol: :lol:

evelkevin

might try a set of Rhodes lifters... :chevy

dlw

Thats basically the cam in my 350. I have had my problems getting idle worked out and its still not right. My next move will be a higher stall torque converter and at some point change the carb also. It isnt much of a hot rod untill it gets up toward 3000 rpm's, but after that its yee hah!!!!!!!!!!!!

73-454

Thanks for your input, I will try adjusting the carb as a last fix and that will be it for this winter. I will try and enjoy the vette the way it is. I bought the vette last fall and upto this point I have done a lot of work the engine is all detailed and the interior is almost perfect. Once the salt is washed of the streets in Toronto the vette comes out to be enjoyed.

Vetterodder

You need a higher stall converter or a milder cam. Ideally, get both unless you have lower than stock rear gears. The higher stall converter will reduce the amount of rpm drop when in gear and result in higher idle vacuum. It'll also act like lower gearing, giving you more low end response.