Alright. I had another thread going about a swap to a 3.8L SC swap, which got shot down pretty hard. Well the purpose was because my transmission was going bad, so I wanted to do a full swap.

Now to specify my goal. My truck is a daily driver, and I use it for SAR. I drive a good distance for most searches, 2-3 hours a lot of the time. I'm actually 1.2 hours from our HQ. If I could work a build on my SBC 350 to get above 20mpg on the highway, I would feel GREAT. Priority #1

It's always a good idea to break the stock performance of a truck, am I right? I currently have long tube headers, wrapped. This follows through with a full true duals exhaust without cats. The truck has a crappy aftermarket intake filter, so I don't really consider that improvement. Priority #2

I love the idea of having a truck that most people never see, which is part of my goal here. I'm working with a local fab shop to build me a new metal dash and door panels to look similar to a bed liner. I'll be redoing all of my wiring and switches in my cab, as well as adding an in dash DVD player. Priority #3

Priorities:
1.) Over 20MPG Highway
2.) Power gains over SBC 350 stock
3.) Custom build

My transmission is skipping second in the 700r4, but I just found out a friend through my SAR team can rebuild it for around $800. That's what finally got me away from a full up swap. (It was going to be $1600+ at another 2 shops)

So I was looking at doing a new camshaft, maybe get some work done on the heads... and throw on a Weiand 144.

Primary QUESTION. For the price of the Weiand 144 and an intercooler setup, would I break 20 on the highway.... AND... Are their better options for the money. Dirt Track Racer 81 has already suggested a procharger as being better, but I don't have a direct link to a kit price.

Please try to remember that my primary goal is not to make stupid amounts of power, but over 20mpg on the highway WITH an increase in power.

1990 K1500.

 

Ill be the first to throw this out there since I know everyone is thinking it, but im fairly certain the absolute easiest way to get better performance and MPG is to do an LS swap.
I messed with an 84 s10 with 3 different small blocks of 3 different levels of build, all with different carbs. and while I was able to break 20 MPG, it was with a 2.73 rear gear and absolutely babying it. Point being, that was a truck that weighed half as much as yours, with much lighter wheels and tires, lowered, and punching a much smaller hole in the air. without a modern FI system, I dont think you can reach your goals. 5.3 with factory injection and an AOD tranny is your best bet for priority 1 and 2

 

I had already looked into a 5.3L or a 6.0L swap on another thread here. Many of them suggested that I modify my SBC 350 to be able to get it. At the time that wasn't reasonable at $1600 to fix the trans. Now it's sounding quite a bit better.

 

A 6.0 will make more power than your 350 with a Weiand blower. Ive installed these before and not impressed with the dyno numbers at all.. The guy I used to work for has an 87 gmc long bed with a cammed 6.0 and on our trip to Amarillo he got 23mph..

 

I get that the numbers aren't that great on the 144. But wouldn't it be better economy than the 6.0?

 

More air = More fuel = More power

without swapping platforms and by just adding a blower your MPGs are going to go down. The blower takes power to make power thus robbing mpg right off the bat. You would be better to go turbo.

Turbos only help with mpg because you can put them on a small engine and make them produce the same power as a larger NA engine when wanted. That's why the ecoboost F150's get 12mpg when you drive them like a 16 year old and 22 if you drive like grandpa.

If you want good MPG and better power look at a newer engine to boost, smaller engine, or something like a 4bt Cummins to swap in. (those things in a truck will get 20+ all day)

 

I get that boosting causes for more fuel... but a 144 is actually worse than a 6.0 or 5.3?

 

While reading this morning on some other various forums about superchargers.. I saw quite a few people in agreement of a different theory with them.

Basically they had the theory that running a supercharger actually could increase the mileage under the idea that the truck is in OD more often because of the extra power. (When your foot isn't into it of course)

Anybody have any thoughts on this?

More air = more fuel; but more power low end = easier travel of the weight.

Wrong? Right?

 

CAM, Small tube or tri-Y style HEADERS, find some vortec heads and have them milled, then sell yours off. Will wake the truck up, give you better economy for the fraction of the price of a blower.

 

I have wrapped headman headers with true duals out. I have no idea what to do when it comes to heads. At all. lol