Chev 350 gurus (help required)

George M. Dailey gmd at tecinfo.com
Sun Apr 13 00:32:42 GMT 1997


At 08:40 AM 4/12/97 -0700, you wrote:

>I was told by an expert to put in a bigger cam 

Oh no, not the expert again! What is a bigger cam? Cams are designed to
creat certain characteristics within certain rpm ranges. Some are for high
end power (+7,000rpm) others peak out at in the low range (-4,000rpm)
If you mix a high end cam with a engine designed for low end power, you get
the worst of both world. Usally at a very high price.

The same guy also says the
>pinging could be due to the advance springs in the dizzy softening when they
>get hot and give just that little bit too much advance (need to check full
>range when engine is hot).

The stock GM TPI system, engine, and cam are all designed to peak the torque
at about 3,600rpm  The ignition timing is also built in and optimized to
"support" this power system. I don't think the "trick" distributer springs
can ever be tweaked to do what the GM HEI EST system can do. This system
will detect a knock and retard the timing for you. I would go back to the
stock cam and ECM and enjoy your hobbie.

>Now here are my questions:
>
>1.  Is this cam an economy cam ?  The guy that ground it said it would be
>perfectly suited for a TPI speed density system (I think so too, got lots of
>power up to 5300rpm, then it runs out of power quite noticeably).
>
>2.  Can you calculate the compression ration from the psi reading ?  If so
>what is the equation ?
>
>3.  If I need a bigger cam, any suggestions ?  Don't forget a standard TPI
>is only good for around 5500rpm.
>
>Help appreciated
>
>Dan     dzorde at geocities.com
>
>P.S. next thing to try is a tank full of BP100 racing fuel.
>
>
>
George M. Dailey
gmd at tecinfo.com




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