Ive search around but im stumped,

i have a 350 block
eagle rotating assembly
850 cfm carb
holley dist.
msd ignition
hooker 2210
proline 230 cc runner heads
10:1 pistons
3500 stall ,th400
4:10 moser 12
pbm power cam
cam specs:
NT EXH
running duration: 287 295
duration:0.050 256 264
valve lift: .537 .557
lobe lift: .358 .371

opens: 29 btc 63 bbc
closes : 47 abc 21 atc

problem was the car kept dying when i put it on drive so i raised the idle to ridiculous levels to keep it running, my current shop is saying its not producing enough vacume, so there working on that , also timing is bad,
any suggestions??

 

have you installed a vacum canister,I had install one on my stroker eng.in my 82 elcomino,if you have canister check intake gasket where it connects to heads. you can use carb cleaner make sure eng. is cold when spraying. on to your timing problem try to set your vaccum advancedto a full vac.port on carb it gave me better throttle response on my eng. when use a timing light what does it read i would like to know if you dont mind

 

The problem is probably the ignition timing.

You'll probably want somewhere near 20° initial timing (what you set with a light by twiddling the distributor), and about 35° of "total" timing (the initial or "static" setting, plus the centrifugal advance), starting at about 1200 RPM fully in by about 2800 RPM; and probably 12° or so of vacuum advance on top of that.

If you have your static timing set to whatever the sticker on the car says, it'll be wrong. Correct timing isn't dependent on the sheet metal, it's a function of the parts the engine is built out of. Your parts require more than the stock "spec".

When you add the other 10 or 15 degrees that the motor needs, the vacuum situation will make a giant leap towards curing itself.

Expect your idle to need to be around 850-900 RPM.

 

good lord!!! That's huge!!! I think you may even need to run your timing locked out at full. Maybe get a starter timing retard setup for your MSD ignition so you can start it. That's a gargantuan cam!

still, you *may* need a vacuum can, but a cheapo one from summit is $30. I think your brakes may become functional with a ton of timing added.


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oh, if sofakingdom meant to use manifold vacuum advance, rather then ported, that'd give you ~32* at idle, which would work nicely I think.

 

hell yea, sometimes it wants to start, sometimes it doesnt, but it sure as hell sounds nice. i'll take into consideration of the advice though...

 

my buddy was able to get the idle down to 1200 rpm, but says the manifold lacks the proper vacume

 

what is your timing, at hot idle?

are you using manifold vacuum advance on your distributor or not?

what is your vacuum at idle?

 

Timing could certainly be a problem, you didn't mention what intake you’re running but that's a lot of race engine for a 10.1 compression ratio unless you’re putting sqezze to it. I have run a very similar if not the same for grind. The only one I knew that made this cam off the shelf was Elgin, a ELG E1090-P. This is a heavy hitter grind, if I remember right Elgin recommended an 11.1 to 13.1 compression ratio . I run dome pistons that come in @ 12.1 compressions. This cam is gonna be a rough idle but tuned you should get a rough heavy lope idle around 900 +/- in drive. I'm pretty sure you will need a vacuum canister, and maybe a 12 volt electric vacuum pump for the power brakes if nothing else. I'm sure you will get it all worked out and that set up should scream. You might try this link to Elgin; it has a lot of good info. My 86 Camaro very similar cam just put me in the 10’s

http://www.elgincams.com/campaper.html

Good luck
Max

 

Might be a back to basics thing here. Have you checked the compression of all the cylinders? If you have an intake valve that isn't sealing or a lot of blow by this can kill your vacuum.

 

TIMING! I am running a 548/ 548 lift cam on my 383 w/ 12* as a base line and total advance at 36*. Get the timing in order, put the carb back to original setting and start from there. I doubt if you need a vacum canister or need to go back to basics. Get your timing right first and like it was said previously you will see a big jump in vacum. 850 is alot of carb, you may need to lean that thing out, make sure you have the right powervalve in it...

 

Timing is indeed the issue here since the original post was from July of 2006.

 

A.) I love how this is 2 years old

B.) I love how vacuum is spelled 4 different ways.

 

It's not my fault, I am a product of Cleveland public schools! And you are right Timing would be the issue!