318 MAX fuel economy builds?

Dmopower said
I don't have any HP goals. This is a temporary engine to get me by while I build something bigger and get my frame tied ect. I understand the bigger port and I have a set of J heads sitting here. But I don't have fuel injection to squirt the fuel down the port so I'm hypothesizing that a smaller more efficient port would move air faster and atomize my fuel more efficiently at low RPM. I have used Rhoads lifters for 40 years to tame street cams but this is only my second attempt to use them as a VVT system at low rpm for mileage on a mild street cam. The other time is my current 273 with a 220 at .050 cam. So far it's working well considering I have a rich carb. I'll address that soon. Let's approach this from another angle. If I get a set of 920's to flow similar to J heads stock how will the smaller ports negatively affect my performance from a mileage stand point?

Going with that 220@050 cam was something along the lines that I am also considering and it’s a Howard’s Hyd grind I’m looking at with the use of standard Rhoads lifters in my 5.9 back by a 727 & a 9-1/4 w/3.55’s on 245/60/15’s. The Rhodes will only be on the intake. The cam is on a 108 LSA. Stall is 2500.
I did want to also use the A-500. This may come to pass later as the tails act has no provisions for a OE floor shifter.

Dmopower said
So I do have the new Rhoads lifters that require adj rocker. I have 273 rockers on my 273 and plan to use them on the 360 build. I am thinking of having them bushed and indexed to 1.55 or 1.6. I have 3 extra sets and figured having one set done to 1.6 and bushed would be cool and maybe beneficial. I see there are a couple guys on here that can do that.

My car weighs 3800 with me in it. 3.55 gears and an A-500 OD transmission. It really is a test of a theory I have as far as the 920 heads go. Like I told 273. If they don't work I can swap heads and someone will want a nice set of 920's.

My car weighs in about the same. You and I are in the mists of testing the same idea. But I have a ‘00 - 5.9.

Dan the man said
Another example of the mileage is going backwards on the newer vehicle's. Everyone knows that the 5th Avenue had zero aerodynamics.

So is my ‘18 Ram 1500 but i average 20+ on the Hwy and have done the best of 23.7. The aerodynamics of the Ram are a brick and it’s a heavy brick!

Bewy said
I would be careful using Rhoads lifters with a mild economy cam. It could be counterproductive because it reduces valve lift at the lower rpms, where economy is made. Every engine has a 'sweet spot' where everything melds for best efficiency & you are seeking the highest efficiency from the fuel used.

I agree. The Howard’s cam I’m looking at is aided with the Magnums 1.6 rocker. I have the math on paper somewhere. So I went with the approximate math Rhodes suggests is happening. Even with the reduction in lift, it gets some back with the 1.6 ratio. Just in the territory of the head needing a really good valve job for best effect.

Personally, I think @Dmopower is onto something and will find out before I do since our builds are a little similar. As I wrote early in this post, my ‘79 Magnum has a floor shift I want to keep and the trans tail or mid section has no provisions for brackets to let the linkage work. I do t want to butcher the floor shifting brackets out for an aftermarket shifter.

Honestly, I’d rather put in a manual transmission.