mrarmyant

Well what's the tightest block huggers produced then? I think I have like a 23" frame rail spacing.

Bilster

iTrader: (21)

I don't believe an aluminum 4.8 was ever made so you are looking at a swapping the crank and rods from a 4.8 into your aluminum 5.3 block. Compression is a mileage seekers friend. Defineltly want to use the 4.8 flat top pistons with no valve clearance "eye brows". I would also think about doing a light mill on the heads to raise compression. If it were my motor, I would look into purchasing a Total Seal Max-seal gapless top ring set. I've had very good success with those ring sets. Good for a noticeable increase in power through out the range. The less you have to put your foot into the throttle the better the mileage.

mrarmyant

Correct. I have an l33 and what is either a 4.8 or 5.3l on the way, owner didn't want to look but it was too good of a price to pass up.

Thanks for the tip on the ring set. I will look into ordering those.

So I am up to

Total Seal Max Seal Gapless Ring Set
LS9 Head Gasket
Slightly Ported/Polished Heads
Slightly Milled Heads

Rymel

will be keeping an eye on this. i only just got into the LS scene and i get the blankest stares whenever i ask about increasing fuel economy...

mark21742

I'd get probably go with an ls6 or small hot cam in 4.8, mill the heads to get your compression up ss high as possible and port the hell out of your heads while keeping or runners on the small side to boost velocity so you can get the 4.8 as efficient as possible just off idle, look for a Yank or some other great converter at around 1600-1800 rpms and you might be show to get as much as 20+ mpg

3.4camaro

iTrader: (1)

You need to speak to a reputable engine builder. This thread is full of guessing. A 4.8l with ported heads is still gonna get better mileage than its stock-headed counterpart. You basically want a small displacement engine with very good airflow. This will allow you to pull back on the throttle position, which saves fuel. Talk to an engine builder about the cam. Internet cam-talk is silly.

wildcamaro

iTrader: (15)

Lots of guessing? It's called theorizing...people like to think out loud...an engine builder usually builds for power not mileage, plus the op posted this in order to discuss ideas, hence not paying an engine builder to do it for him...

mark21742

Grated It's a Dodge, but from day one my father was getting an average of 10-11 miles per gallon out of his 318 in his Dodge Ram. I swapped it out for a 360 and all I did was port the heads, intake, tb and shorty headers.....the 360 now gets an average of 16-17 mpg, not theory, its fact.

99Bluz28

iTrader: (35)

As far as cams get one that'll maximize your power in the rpm range you'll be in most often. Have a shop spec a custom cam grind for your intended use.

Socket

iTrader: (6)

I had a 2000 half ton Silverado extended cab Z71. It had the 4.8 and a 5 speed. I would get 20-22 mpg all the time on the highway. I got 24.5 on one long trip with it once. The only thing I had was a K&N CAI. I would put a 4.8 in it and a 5 speed with a free flowing intake and exhaust. If you are going to go with a non stock cam then I would talk to an engine shop. Yes they may typically build for power, but that's because that's what their customers want. I would bet they could be a help.

LS1 Racing

iTrader: (15)

I did a 2007 4.8/4L80 swap into an 1977 Camaro. It had a custom tune with decent performance, and easily got 29 MPG on the highway with the stock 2.56 open rear.

I eventually put 3.08s in it and only lost 2 MPG but still went mid 14's at the track.

All in all, a pretty good MPG combo.

mrarmyant

Update on the swap, it went to an L33 as is with some HP goodies. But the guy who is doing the wiring harness is someone no one should do business with.

I have been working with Bill Hillock of BP Automotive for a few years now to get an LS harness made for my L33 swap into a gen I 4runner. Orginally the kit looked good for 600 dollars plus my harness, decent fuses, etc. Service was slow, turn around was about 3 months. I then moved, got settled in a new shop, and started back on the project. I wasn't happy with the fitment, adjusted the lengths of wires as I wanted them and said I'd pay his 50 an hour in bench labor rate to have them adjusted. After calling and emailing weekly for 4 months, he finally answered after screening all of his calls and said sorry he's swamped it should only be an hour of work or I can give you a Camaro harness as thats about the same length because someone else used it on deposit and backed out. Said he was fine doing it for me saying in the forums how resilient his setup was, etc. (which it is) I said fine. Another month passes by, I start messaging him by personal email, business email, eBay messaging, and Facebook with no response. After a threat to post about his business practices online after a month of emailing weekly I received my harness back in the mail with ends missing, no work done.

If anyone would like his emails as proof, phone records, or all of the emails he refused to respond to (which by the way if you call his number he states he only responds via email) I would be happy to provide them.

STAY AWAY AT ALL COSTS. He promises a lot and delivers nothing. I'm out about a years worth of time and about 600 dollars.

Name: Bill Hillock
BP Automotive
Website: http://www.bp-automotive.com
Storefront: http://shop.bp-automotive.com
eBay: http://stores.ebay.com/BP-Automotive-and-Wiring

99Bluz28

iTrader: (35)

Sorry to hear you've had a bad experience with one of the sponsors.
So, have you already post this in a new thread in the Sponsor Feedback section...?
https://ls1tech.com/forums/ls1tech-s...&daysprune=365

mrarmyant

I had issues finding that. Thanks!