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Old 10-01-2011, 02:00 AM   #1
Join Date: Jan 2009
Posts: 42
Default No low end power and rough idle

Hi, I have a 77 425 with minimal upgrades.

My problem is that my idle is extremely rough and I have no low end power. I have had this car for a long time and when it was running at its best I could peal out in it all day long, and even before any upgrades. It just wont do that at all anymore.

At higher rpm it runs pretty well and has a nasty (good) growl that is most likely due to the Quadra-Jet oversized valves and free flowing exhaust. My secondaries are deffinately opening although it takes a while for the car to warm up to the point that they will open.

Really when it boils down to it power is good at high rpm but honestly I feel it might be missing a little there as well just because there is an issue at low rpm that I am guessing is effecting high rpm as well just not as noticably.

Timeing seems to be on (had it pinging and backed it of to where it just barely disappeared)
Vacumm is low but just barely at about 16 to 18.

Here's what I've done to it.

Fully rebuilt
Oversized Valves
very mildly ported intake
.30 over
upgraded rockers not rollers or ajustable
Cloes Timeing chain and gears set at normal position not advanced or retarded.
Earlier style exhaust manifolds off of a 472 or 500 cause I had a cracked one
2.5 in Y pipe into 3 in high flow cat then into 3 in single in 2.5 dual out muffler
Stock rebuilt Quadra-Jet

I just want that low end power back. Any ideas?
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