Thread: Low engine vacuum but no vacuum leaks.

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Originally Posted by 47Fordcoupe

Probably the same issue as me..too big a cam for a pretty stock engine. Big cam= low vacuum. Most vacuum I get is about 10''. I had to install a vacuum canister to help with the brakes but that made no noticeable difference.

It's a common problem in the hobby. Nobody understands that the cam is NOT a free-standing part, that it relies on every other part of the motor and drivetrain to operate as a team toward a desired end.

When my youngest son was growing up, racing go karts and motorcycles, I was teaching him about ****THE COMBINATION****. It is not one part or only a couple of parts that make a winner.....it is ALL THE PARTS working in combination with each other that makes a winner.

His buddies who used to come around to the garage and ask me about a cam for their ride used to call me "Mr. No-Cam" because of the mild grinds that I would recommend for their motors. Then I would have to explain the awful truth to them, that their motor was somewhere between 7.75:1 and 9.00:1 static compression ratio, a range that will not support a cam that idles with a "rump-rump". Some got it and some didn't, just like my audiences on Club Hot Rod and other sites.

This may come as a surprise to some of you, but you can make a WAY quicker ride by changing the torque converter and rear gear than you can by changing the camshaft. A 3000 stall 10" converter (yep, still streetable), together with a rearend gear change to 3.73/4.11, will make you think you did an engine swap.
https://www.youtube.com/watch?v=njL2x-msbZQ
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