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Drinks Gasoline
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Discussion Starter #1
Started reading on various LT1 sites about the simple changes to improve performance. Looks like rockers are the most cost effective change.

Car is very low miles. Looks like if I went to 1.6 ratio rockers I could get away with my stock valve springs for quite some time.

Anyone know of 1.7 rockers on the iron heads?

Last question, anyone care to comment on their fuel economy after doing the rocker swap? This is my daily driver, so I'd prefer to keep fuel economy losses to a minimum. I got 18+ mpg filling up today, and I've been averaging about 17.5, would like to keep it up toward that way.
 

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Super Moderator
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Rockers wont gain you much without valvesprings to compliment them. The stock valvesprings are unlikely to break but that is not the measure for actually working. Stock springs with stock 1.5 ratio were allowing guys to document valvefloat a decade ago. Low miles or not yours are going to be soft and not going to control the valves well. How this hurts performance is by letting the valves bounce back open when they close.
Rockers wont hurt mileage, mileage is primarily about the work needed to accelerate the car and push it through the wind.
 

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I'm no expert, but I haven't heard much about going to 1.7's. 1.6's is a common upgrade along with springs. Increasing power & maintaining MPG is a tough act.
 

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Having HP potential doesn't hurt mileage much, USING HP does.

My car gets better mileage than my truck despite a couple hundred HP more a LOT deeper gearing and the 3800stall. Hell my car is high teens compared to low 20s for my stock wagons on my commute. Sure it is 5-600lbs lighter than a wagon but nearly twice the HP, 4.10 gears, 3800stall. IMO 3mpg difference given that much HP and that aggressive a drivetrain is peanuts. and there is a LOT of room between stock and what I have
 

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Drinks Gasoline
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Discussion Starter #5
I can't deny a certain tendency toward flooring it when idiots around me get on my nerves...

I may do it, I may not. We'll see. It's like some of the other mods I've seen, like where people delete the muffling baffle "first base", where I wonder if they really get true improvements, or if it just makes more noise, kind of like flipping the air cleaner lid upside down on carbureted vehicles...
 

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First base delete has been documented as something like a 6hp gain for $10 in PVC pipe, home plate does not hurt power.

Have you done the "swiss cheese" airbox mod? The stock airbox only flows like 450cfm.
TB coolant bypass is worth power too.
Do all three you will be over a 10hp gain at higher rpms for like an hour work and $10. Take a little extra time and clean the TB and IAC.
 

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Drinks Gasoline
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237 Posts
Discussion Starter #8
Even if I have to change studs while the valve covers are off, that's not a terribly big deal, assuming that it's a matter of pulling the covers, pulling the rockers, and then pulling the old studs, and installing/torquing down new studs.

I'll look in to the first-base removal. I might want something a little better than ABS-plastic plumbing fittings glued together, I might have a solution for deforming a single piece of pipe so that I wouldn't have to use such fittings...

I may look at finding another air cleaner box to drill out, though I may look at enlarging the single existing intake hole rather than adding more holes. This is my daily driver and needs to maintain the qualities that my wife likes, and unfortunately her strongly positive "couch on wheels" feelings go along with enjoying the power, so I need to keep the comfort level up. Too much intake noise would be a problem...
 

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Back in Black
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Drilling extra holes in box does not make a big change in noise level in the car. She will probably not know, did this to my regals and impala and wife did not notice a thing, even did it to her Olds Van.
 

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Even if I have to change studs while the valve covers are off, that's not a terribly big deal, assuming that it's a matter of pulling the covers, pulling the rockers, and then pulling the old studs, and installing/torquing down new studs.
Point being is you need to TAP the stud holes...really not something the average Joe should be doing ON the car.

1.6's w/press in studs not seeing alot of 6k+ rpm runs should be ok.
 

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The roller rockers don't care if the stud is pressed or screwin, but the stock iron heads are pressed.

I haven't ever seen anyone build a 1.7 in self aligning which is what you need with the pressed studs. There are a LOT of self aligning 1.6 rockers out there for a 3/8" stud which is what you would use with stock studs.
To run non-self aligning you need screwin studs to bolt the guideplates down with.
 

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Drinks Gasoline
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Discussion Starter #12
Gotchya.

The engines that I've worked on use rocker shafts, where the eight rockers and spacers on a side mount to shafts that also serve as the source of lubrication, so changing ratios, within the scope of the geometry of the shaft position, is just a matter of sliding the old rockers off the shaft, checking for wear, replacing shafts if necessary, sliding the new rockers on to the shafts, installing the shafts/rockers on to the heads, paying attention to get the pushrods properly seated against the rockers.

So, with these stud-mount rockers I'm still learning.
 

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Creepy Ass Cracker
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This is my daily driver and needs to maintain the qualities that my wife likes, and unfortunately her strongly positive "couch on wheels" feelings go along with enjoying the power, so I need to keep the comfort level up. Too much intake noise would be a problem...
Yet another reason I'm alucky man.Mine's our daily too,and my wife LOVED the sound after the new intake LOL Though,she won't let me put 5 racing buckets,and harnesses in it.Go figger:gaah:
 
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