Better mileage and power for a 96 Lumina 3100

[GLHS]

Hello everyone,
Have been doing some reading on this site and am wondering if it is possible to pick up 10-20 hp and maybe a couple of miles per gallon with simple mods.
From what I have read I can do a intake manifold and throttle body swap from a 2000 up that will help?

The engine I have in the car currently has 210,000 miles. Would a new timing chain be beneficial?
The car runs well and uses almost zero oil between 3,500 mile intervals.

Thanks in advance.
Kurt

[GLHS]

Nobody?
Is this in the wrong forum?

[IsaacHayes]

Chain is probably stretched, that can help. New O2 sensor if it's old ( go with ac delco or denso)

lower intake gasket ever been replaced? larger intakes probably do help some. Make sure you have roller rockers before you swap the lower on or you'll have to swap to them if your heads have notches for them or grind the lower intake to clear the old style rocekrs. Most 96 got rollers and I think all 96 heads had notches to accept them.

[GLHS]

O2 sensors have been replaced with Delcos from the dealer.
Lower intake gasket was changed 15,000 miles ago with one from Napa. It was a metal gasket.
Pretty sure mine had rollers.
How long does it take to change the timing chain?
I've been reading but have yet to find anybody who has given a report of better mileage by doing the swap.
Just wondering if I can find the upper and lower manifold with throttle body and EGR resonably priced if it would be worth it.