Major engine swap advice?

[Clyde9]

From: ZR91  (Original Message)
Sent: 2/26/2008 12:34 AM

Ok, I need your help and advice...

I am seriously contemplating pulling out the 440/727 auto and installing a 1998 5.7 Vortec/4L80E from one of my 1 ton shop trucks.
Why?
Better fuel economy, easier upgrades, and a 4 spd auto.

My motor home has 4.10 gears, and weighs 10,500 pounds. It gets around 10-11mpg(US) and revs around 3,000 rpm+ on the hiway.

My crew cab has 4.10 gears, and weighs 6,500 pounds. Last week I pulled a flat deck trailer(4,255 lbs including load) I also had 1,650 lbs in the box of the truck(weighed at a certified scale).
Still, I was only at 2,100 rpm on the highway and I averaged 17 mpg.
I have to assume that if I did a cold air induction, MSD ignition and headers on the 5.7 it would be more efficient yet.

Jay



From: denisondc
Sent: 2/26/2008 8:05 AM

If you do this I hope you will give us the results. I prefer to keep mine original, it has worked so well for 36 years.



From: ClydesdaleKevin
Sent: 2/26/2008 9:19 AM

Let us all know how it works out Jay!  It sounds like a great idea, and at today's fuel prices, almost doubling your fuel economy sounds more than worth the effort...and fuel prices are only going to continue to rise.

Kev



From: ontheroadagain7
Sent: 3/2/2008 4:59 PM

I have been thinking of  installing a fuel injection system and overdrive transmission on my small block Chevy but I don't think it will improve the mileage that much from the info I have read about newer models due to the aerodynamically challenged design of a box on wheels so I will keep the trips short and keep it at 55 most of the time



From: Froggy19362
Sent: 3/4/2008 2:44 PM

Hi After experimenting with MPG 55 is defiantly the place to start , But try this 57 MPH it increased my MPG from 9MPG to 9.5 it sounds and feels like it is not working as hard,  with the slight increase in RPM , it actually means higher RPM = less fuel.   Doesn't seem to make sense but the no,s bear it out ,Now road conditions head winds terrain all effect these things.  I will keep experimenting though,  Having cruise control is also very important , I started doing this with my car same results but its very hard to drive a car at 55,57 MPH  it seems like you are parked .   Traffic hates when you pass a slightly slower vehicle as it takes a wile to clear but if you are serious about fuel you must be very diligent. When making stops prior slowdown will eliminate long idle (cool down periods) And no hard acceleration when reentering traffic (this can be difficult if the roadway is busy)  long idle waits can destroy results  One good thing this kind of driving can help you to stay awake as it requires paying close attention to what is going on up ahead.  My next step is dual exhaust   with high flow mufflers and headers, Then a four speed auto trans w OD & lock up converter  This 1977 Chev 350 powered Quadrojet 3 speed auto class C rig weighs in a 6 Ton I run 65 PSI in all tires (10 ply radials) Has 80,000 mi original engine . But filling a 50 gal tank @ $4.00 a gallon is frightening.  Happy Motoring The 2008 season is right around the corner.  Frank



From: Froggy19362
Sent: 3/4/2008 2:57 PM


Sounds  like a great idea since you already have the necc parts (i take it the late model truck is unusable) You will have all the necc brackets mounting fixtures cross members etc. if the transmission is electronically controlled you will need to check for any temp sensors in the radiator etc & use truck wiring harness & control unit, The fuel injection  will require a high pressure pump which is probably in the tank on the truck, But I'm sure some speed shop has an external replacement, Also return fuel lines your original vehicle does not have. You will run into many differences but i think you can overcome them all. Being a master mechanic who can weld and fabricate will help the most  good luck Frank