318 Build suggestions
I, for one, am so sick and tired of hearing "Scrap the 318 and go find a 360" some of us happen to like the 318.
Comparing the ones that I have had, the 360 hasn't done anything for me that a 318 wouldn't or couldn't, except that the 360s I have had have been alot thirstier at the pump / for really no noticeable performance difference.
As to thirstyness; I beg to differ;
I have built a 360 that went 106 in the qtr, at 3650 pounds, and made 32 mpgUSg on the hiway at 85=2100rpm, and as a general average did better than any 318 I have ever had or modded.
I'm glad you like 318s.
But quit feeling hard-done-by; if you like 'em that's fine. That's an opinion and there is no argument against an opinion of liking something.
I am NOT a 318 hater; they have a their place in the Mopar hall of fame. But given a choice between using any SBM for a performance streeter at a 3600pound load, ......................
I will always chose a 3.58 stroke. And the primary reasons (not opinions) are;
1) more effective stroke left over after the intake valve closes, at any given Ica. This leaves more stroke with which to build pressure, and pressure is power. And
2) about 15% more VP at any given Dcr. and that means a stouter bottom end and therefore a lower stall or less starter-gear, is possible. And
3) more rpm, lots more rpm, before the power dives. This allows you to leave it in a particular gear just a lil longer. And
4) there are several more
Straight Hi-way mileage, build for build, depends mostly on the guy tuning it.
In a given vehicle, cruising at say 65mph, requires a certain amount of horsepower, period Whether you do it with a 318 or a 360 is almost moot. Since the 360 is ~13% bigger, you can easily run less gear for the same performance. Mopar gears are stepped about 10% apart. So running a 318 with 3.55s is about 65=2900, and running a 360 with 3.23s is about 65=2640; so right there is a headstart to economy. It has been stated many times that a reduction of 10% rpm is good for an increase in economy of 5%; so from say 20mpg in the 318 to 21 in the 360. That gives you one full mpg to give up to friction in the 360. Build for build, IMO, that will never happen.
The 360 running 3.23s, build for build, will hang with the 318/3.55s no problem.
As for hiway fuel-economy, if you build a 360 for economy, it will kill your 318 that's built for performance, and IMO, in the zero to 60 contest is not gonna give much up if anything, to the 318, after you equalize them on the starting line; cuz the 360 is gonna have a serious tire-spin problem.
Think about it;
there is nothing a performance 318 can do, build for build, that a 360 can't do better. Build for build, and gear for gear, a 318 can edge out a 360 in hiway economy; mostly because of internal friction , in dragging slightly bigger diameter rings, slightly further up and down the bores. And maybe you can find one or two other legitimate reasons but those will be small contributors.
But then, build for build and gear for gear, that same 360 will kill the 318 in performance.
Here's my opinion; "I, for one, am so sick and tired of hearing"
how sucky a 360 is compared to a 340, never mind the little brother-318.