New everything... not enough oomph

[-83MONTESS-]

Put a in a decent cam and change the gears. Regardless of what you do its gonna be a turd off the line with the 2.73's.

My ultimate suggestion would be what Driven suggested. 2004R and a 3.73 rear end. You will have an overdrive for highway mileage to keep the RPM's down and lower gears to help get out of the hole. Best of both worlds.

I would do the latter before a cam change but regardless thats a pretty lame camshaft.

 

[Texas82GP]

It's weird for me to say this (I'm 42, so I lived through the 80's and the anemic cars of the era) but 300-350 HP is not a big deal by today's standards. Our family car, a Buick Enclave, has a 300 HP V6 but lord it's heavy. 350 HP can make a pretty snappy cruiser but the setup has to be optimized. If it were me I would likely go with a 200-4R and 3.42 rear gears. Depending on your tire height, maybe a 3.73. Also, it's said you can get better fuel economy with a custom tuned Quadrajet (small primaries) than with a Holley, though I don't have direct apples to apples experience to say so authoritatively.

 

[olds307 and 403]

As said OD and 3.73 gears, I picked up .5 in the 1/8 mile going from 2.56 to 3.42 gears. A 750 cfm carb is a good upgrade, go 750 Street Demon if you care about maximum mileage. I blew the doors off one of those 300 hp V6 Chevy crossover POS when my Cutlass was running mid 14's.

 

[Wageslave]

It would not be a bad idea to ditch the engine mounted fan and install electric fans. You are pretty far under the curve with fuel mileage, and those fans are costing you fuel to run whether you need them or not.

 

[64nailhead]

As much as I want to do that, I can't as I figure that would put me to 6-8 mpg and I would be cruising at 32-600

Just noticed this - swapping in a 200-4R and 3.42 gear will put your 70 mph cruise rpm well under 2200 depending on tire size.

I tell my wife every time she asks why I work on the car so much, "I'm just trying to make this car faster than your 96 civic coup (no mods)".... and she gets 28mpg. I'd still rather drive the wagon.

I was getting 19 mpg with a 200-4R, 3.73 gears, 27" tires with a FI 327 with a turbo (made 500 HP). It's possible to get good fue economy with all the parts working together.


Where do you live? I ask as if local (mostly) we could have a fun testing weekend. I have a spare stock 200 and spare G-body rear with 3.73's. The rear could be swapped in less than 3-4hrs. It would be a great test for you to see how it would work. I'm sure you would be shocked. But I still stand by my previous post that your cam is costing you alot of performance.

p.s. - hopefully we didn't lose the OP :-/

 

[olds307 and 403]

If your car does a lot of highway driving why did you go TH350? With stock tire height, you will be running around 2500 rpm at 60 mph. A 700R4 or 2004R will drop the rpm's considerably. Remember it is not just the .67 or .70 od ratio, the lockup converter drops it another 300 rpm. With the converter locked up with stock tire height, I ran 1850 rpm at 60 mph with a 2004R and 3.42 gears. With a 700R4 it would be around 2000 rpm at 60 mph. For more bottom end power, get a cam ground on a 110 lsa. As I said, a Street Demon 750 by design will add power and fuel economy, probably out of box for your combo. But like any carb should be tuned to the combo.

 

[lilbowtie]

Lot of advise given here - non of it bad! 290 HP engine set up properly can net you a 13.0 1/4 mi ET, pretty quick. The rear end needs to go, that engine is working hard to get moving - as stated you will probably pick up mpg. You changed the heads (great choice) but with the 185 runners your taking away from bottom end. Using the 1.6 rockers are also taking away bottom end, with the 2.73 rear end = loss of oomph. I'd also guess if you used wide band tuning you would be pretty rich with the hit of the squirts. You never mentioned anything about a converter?? Put your complete package together and I think you will be pretty happy.

 

[-83MONTESS-]

Also, it's said you can get better fuel economy with a custom tuned Quadrajet (small primaries) than with a Holley, though I don't have direct apples to apples experience to say so authoritatively.

This^^^ I loved my Q-jets for this very reason. If I ever have another older vehicle for a daily it would have a Q-jet on it. Find someone that can actually tune it and knows what's going on and you will be golden.

I don't see why a properly tuned Q-jet, 200-4R with lockup and 3.73's can't get you close to 20mpg consistently - even with a better camshaft. The ultimate budget cruiser IMO

 

[testcase448]

There is no such thing as enough "ooommmpph"
Having said that I've seen this farly frequently, your combo isn't right.
Start in back, dump those airplane gears, get an overdrive trans, but to be honest a 3.73 and a T350 isn't all that bad to drive.
That cams wrong for what you're trying to do, and I expect a set of 1.94 valves would actually feel quicker on that combo
You stated your initial timing, what's the TOTAL and when does it come in? In that wagon you want as much as fast as you can get it without detenation.
Is the Holley set up right? Squirter cams what they should be? Vacum spring right?

 

[el camino ss 84]

If you stay with a turbo 350 trans maybe convertor change then I would go to a 3.08 rear gear and then change cam to a more low to mid range torque curve where you use the power since it's a daily. It would probably pick up some mpg. Also a cheaper option is screw a pedal stopper to bottom of gas pedal so you don't use as much throttle instant mpg.