What Cam??

[wxman1]

I bought the blue beast several months ago. Previous owner said
the engine had been rebuilt and that it had a comp cam put in it.
Did not have any specifics on the cam...I think a buddy of
his actually did the "rebuild". Any way...the engine seems to
run ok...except that it idles sort of rough. Seems to lope.
The lope gets rougher in cold weather. My brother mentioned
that it might be a "3/4 cam". Ive tried calling the guy back
to get more info but his phone has been disconnected.
So I'm wondering how big a job it would be to replace this cam
with the "stock" cam. Or possibly would the engine idle better
if I played with the timing?

Any suggestions are appreaciated!

Jim M.
Mt Juliet

_________________________________________________________
69 C10 Fleetside
350CID/TH350
3.73 rear end

[crazy longhorn]

Ahh , vacumn issues..... i would try playing with the timing. if you are running a pretty 'warm" cam, try to shoot for 12-14 initial, & limit the vacumn can to 8-10 degrees,& hooked to full manifold vacumn at the carb. some where in the range of 20- 22 degrees @ idle (with vac can hooked up) will clean up the idle, & givebetter low end responce. i like to see the total @ 34 degrees between 2800-3200 for all in(vac can disconected & plugged), if you are running pump fuel. good luck.....longhorn

[Truckstr]

Jim,

It's not that big of a job to replace the cam on one of our trucks - unless ya got ta do it outside this time of year .

I think that I would "play" with the timing a bit before I went to a different cam though.

What is the initial timing set at? Are you using the "spark ported" vacuum on the carb. for vacuum advance to the distributor? How about the idle mixture screws on the carb. - how are they adjusted?

Later,
Jeff

[stllookn]

Many companies will stamp or etch the cam specs on the end of the shaft or at least a number that allows you to identify the beast and decide if you want it. A choppy or lopey idle or results from cam overlap and duration. These are necessay evils when trying to get additional power at high rpm. You can get a smoother idle with a cam designed for lowend to midrange torque which it sounds like you would prefer. I would read John Ligenfelter's book on modifying small block Chevrolets, identify your cam then make a selection you can live with. $15 for the book and a couple of evenings reading and your brother will think you are a genious when you ask him just what duration, overlap and lift would constitute a "3/4" cam...LOL! Knowledge is power!

[Tom]

I can understand replacing the cam with one you pick so you know the specs and that its what you want, but a stock cam????