Do A few weeks ago I got wiped out at a red light. Still waiting on insurance to get the bs handled but ran up on a deal on a 07 1500 quad cab 4x4 with a 5.7 hemi with 135000 on it that I couldn't pass up. It's in damn good shape front end seems to be pretty tight still minus a wobble from 60-70. It's got a semi aggressive set of mud grips on it so I'm hoping it's just needs wheels balanced. Now I'm a Ford technician with a Hemi.😂 Love the truck though. I've read up on characteristics of the hemi quit a bit and fuel milage seems to be the biggest downfall. Obviously intake air and exhaust is the go to to get a few more outta her. What y'all's recommendations? What's some things I should look out for as know issues that will arise with this engine?​​​​

 

By 2007 you should be good. Intake and exhaust will only net you more noise; a tune will do more for it. The weak link in this chain is the RFE trans.

 

What is your setup, and what do you want to improve?
What is gear ratio and tire size?
I think your stock tires were 275/60/20. If tires are bigger than stock then your speedometer might be off and show slower speed and lower mileage than actual.

 

33/12.50x20 tires. Ive got the OEM spec sheet at work I'll check tomorrow on rear end. The speedo is only 2 mph faster according to GPS on my phone. Average 11 in town 12.5 highway on cruise. I'll be doing a tune up pretty quick to see if it gets a lil better.

 

The tranny seems really smooth right now. I'll be servicing it soon to gauge it further. She will have a easy life with me. Less then 50 miles a week and the occasional trailer to the dump will be the hardest it'll be pushed. Thanks for the insight on the intake and exhaust.

 

2003 Hemi. Empty, loaded, 20mph, 80mph. 12mpg always.

 

I had a 77 Blazer that was like that. Didn't matter what I was doing, empty, fully loaded, pulling a trailer, packed full of gear, 11 MPG. Never varied. And that was carbed.

 

If you're gonna leave it bone stock then you should be fine.

 

The 545RFE is a pretty stout tranny, as far as I'm concerned. 338K mi on my Dak and it has never hiccupped. Mostly light duty, but I've towed cars from state to state too. I changed the fluid and the two filters when I got it, installed an aftermarket drain plug and perform a single drain/fill every 25K since that.

 

Once you get past eagle level power (and don't dare touch the TM) it's on borrowed time. On my 4th one and only the last two had to deal with a mild cam.