Impressed with increase in gas mileage with square body!

[chevymotocross]

Thanks everyone!

2badgn, forgot to mention that. After deployment, a cover will be the first thing I get for the truck! Also, beautiful looking truck! I remember seeing a thread with some more pics of yours, I love the factory look of your rig!

Another thing I forgot to mention. The EGR system. I currently have it blocked off. I replaced the OEM gummed up EGR a few years back. I wrote the factory EGR numbers on the new EGR, but I remember there was no P or N at the end of the numbers to represent positive or negative backpressure type. After removing the cats and dumping the exhaust, I was getting code 32 on the freeway. Also, my truck was stalling occasionally after highway use at the exit ramps. I don't think the EGR was closing properly causing a vacuum leak. Come to find out, the replacement egr says POS on it. I believe I need a NEG backpressure EGR especially since I have no cats and the exhaust is dumped.

Since I plugged the current EGR, there is no more stalling but a properly working system will probably yield better mileage.

[turbo350]

Originally Posted by chevymotocross

Thanks everyone!

2badgn, forgot to mention that. After deployment, a cover will be the first thing I get for the truck! Also, beautiful looking truck! I remember seeing a thread with some more pics of yours, I love the factory look of your rig!

Another thing I forgot to mention. The EGR system. I currently have it blocked off. I replaced the OEM gummed up EGR a few years back. I wrote the factory EGR numbers on the new EGR, but I remember there was no P or N at the end of the numbers to represent positive or negative backpressure type. After removing the cats and dumping the exhaust, I was getting code 32 on the freeway. Also, my truck was stalling occasionally after highway use at the exit ramps. I don't think the EGR was closing properly causing a vacuum leak. Come to find out, the replacement egr says POS on it. I believe I need a NEG backpressure EGR especially since I have no cats and the exhaust is dumped.

Since I plugged the current EGR, there is no more stalling but a properly working system will probably yield better mileage.

Sweet rig!

I had an '87 350 tbi in a 3/4 ton conversion van. Best that van ever saw was 12, maybe 13 mpg even when it was new. Had 700r4 and 3.08 rear and of course the heft and bulk of the van. Using that for a very loose comparison I'd say you are doing a heck of a job and squeezing out the max amount of economy out of what you have.

[pig rig]

Ive got an 88 with the 454 tbi in it Ive done a lot to get more power out of it and in the process of that I went from around 10 mpg to 12 mpg then we took atrip to socal in it and on the way home the clutch fan went out so I pulled it off and for the last 600+ miles I got just short of 16mpg out of it.
so I put electric fans and I did some reading on the advantages to running an MSD 6al spark box so I added a 6al and an MSD distributor and new injectors
but Ive developed engine problems and I still havent been able to do a few hundred mile road trip to see if its improved.