another point of reference, my 5th ave I have a mag headed 318, 9:1 comp, with a 259/259 adv, 208/208@.050, on 112LSA cam, A500, 27" tires and 3.55's....65mph is ~2000 RPM. my commute is 2 lane, with a somewhat hilly portion, doing 55 mph (~1800 RPM), I've never had it lug/surge or downshift.

same thing with my old motor, which was a stock long block 360 with a comp XE262. the old motor would surge a bit at 45mph in OD, the new one doesn't...

if it were my car feets, even if it is heavy, I'd go 3.55
s-3.73's, since you'll probably be running 28-30" tall tires, your 518, and a higher stall lockup (2800-3200RPM) to get the weight moving from a standstill.

for a cam, I'd probably run bullet's HR276/378 lobe on the intake, probably a 114 LSA, installed at 108, not sure on the exhaust, if you want more or less duration on the exhaust with a turbo car...I'd personally build the engine with an idle-5500 RPM powerband...

uhh, again, the torque/HP peaks you usually see are based on WOT....run a dyno sweep of the motor at 1/2 throttle and see if the HP and tq peak RPMS change....

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Yeah and you'd still be in better shape than you would below the operating advertised range of the cam.
Your new vs old motor is a good example of what I'm saying, again.

However, I do agree with the advice you give in the above post about cam range idle to 5500, thats where he needs to be if he's putting mph over power/rpm.

I would say with a cam like that one mentioned, a cruise rpm of 2200 rpm would be nice.

To all those who understood what I said, thank you.
To all those who didn't understand but then gave examples proving true what I said, thanks.
And to all those who decided they would chime in about nothing other than my delivery of what I said, thanks but don't worry about me.

ps, When I do the caps lock deal..it's more of a LOL while responding.

Is the truck gassed up and ready to go with the trailer hooked up already?

My 408 stroker is running a Mopar 508 cam which has a recomended operating range of 3000-6000 rpm and I get my best gas milage at 2300 2500. Anything above that and my milage drops rapidly.

(I said to keep it to the argument and knock off the personal attacks)

Post deleted by moparts

Post deleted by moparts

Before I did the big super duper MPG 318 build I had the bone stock 318 2bbl in my 68 cuda, it came with a 2.76 gear and cruised well below the 2400 RPM TQ peak it came from the factory with, now I had an otherwise identicle rear end with 2.94 gears and thought I would swap it in for a little more acceleration and to get it up higher RPM at cruise because like you I though it would get the best MPG cruising at the TQ peak, that is when I found out I was very wrong, cruising was right at 2400 RPM however MPG went down drastically, next rear end swap was to a 8.75 with 2.76 gears and MPG went right back up to where it was with the 2.76 7.25 rear even though RPM was once again well below the TQ peak. After that I built a 904 with LU and brought RPM down more and MPG went up another 1mpg.

After that I built a similar motor but with a few changes, the compression was increased, I added a 4bbl carb and headers, so the peak TQ RPM should have gone up significantly (I never dynoed it) and it definately felt like it did but guess what? MPG went up a bunch more. I got a best of 29mpg lugging the snot out of that motor well below the peak TQ. I really wish there had been higher gears available for the 8.75, I am sure I would have gotten over 30 MPG with that combo. That motor was not working hard at all to pull the car at that high of a gear, even at 70 mph (2200 RPM) it was still pulling 17 inches vaccume so there was way more power there than was nessacary.

Cruising at your peak TQ only gives you the best MPG if you have to run WOT to maintain your cruise speed at that RPM.