Thread: Engine Lacks Power

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I just completed an engine rebuild got it timed etc. The problem is it lacks power from start to about 55mph. I have 20inch pounds at a high rpm 2000 and greater, but at idol it is about 5inch pounds. Do I have a to low of vacuum?

Plugs and wires are fine. It has Edelbrock cam/ lifters / carb and intake package. 350 chevy stock pistons and heads. Oil pressure is great.

Thanks for all who respond.

vacume is measured in HG, do you mean vacume? if so, there is a vacume leak in a line probably, closing shut at high rpm's. maby a carb gasket. you should have at least 15 Hg at idle and that is on the low side, 16-18 is great

Vacuuum is measured in inch lbs of water column/ mercury, but reguardless I think were on the same page. I am using a Craftsman tool that shows inches of mercury. It also has mm Hg and it is only 5 when at idol. I saw somewhere that 17-22 is what you want, but I didn't know if that was at idol.

Thanks

Originally Posted by 81fleetside

Vacuuum is measured in inch lbs of water column/ mercury, but reguardless I think were on the same page. I am using a Craftsman tool that shows inches of mercury. It also has mm Hg and it is only 5 when at idol. I saw somewhere that 17-22 is what you want, but I didn't know if that was at idol.

Thanks

actully just inches of mercury, it's measured by how many inches mercury will be pulled up, same way barometric preassure is. you should be able to maintain somthing like 18" of HG @ 800 rpm on a stock engine

Sounds like the vacuum is too low to pull the centrifugal advance in the distributor. When you measure your vacuum, are you measuring ported or manifold vacuum? Are you checking it at a port above or below the throttle blades?

re set the timming make sure you are on ported for the dist pull and recurve the dist

The vacuum I am measuring is off of the intake. I took off the transmission vac to modulator line and took it there.
Thanks

Is the vacuum advance on your distributor working???

sounds totally like a vaccum leak, get some carb cleaner and spray it around the edges of your intake and carb gasket.... if your vaccum gauge flickers or idle changes.... then you know what ya got, WD-40 also works oils are natural sealers.....if not then i't could also be a very poorly tuned carb, or not enough advance in the distributer.... or a combination of both