Does anybody have a '78 or '79 4x4 with a 460/ZF5 and 3.50 gears? Bronco or F150. how is the torque at freeway speeds?
I'm in the planning stages for a 78 Bronco re-build. it will be a street cruiser with some trail use. absolutely no hard-core or rock crawling. must be able to do 350 miles at 75mph. (with many stops for fuel)
right off I have the wrong engine configuration, it started life as a 1970 429 SCJ and was bumped up to 460~466 cu in during a past build. I can see smaller heads, cam & intake, and probably EFI, to get the torque down lower. I see no need for anything over 5,000 rpms as I'm retired now and can't afford new parts every 2 weeks!!
the C6 is going, putting in a ZF5 and keeping the NP203. 9" + D44. the gears are 3.50, I think, it's been many years.
ran some numbers, 30.9" tires should get me 2243 RPMs at 75 mph, 33.4" should be 2063 at 75 mph.
do those RPMs sound reasonably for a mild 460? I know a true SCJ would choke at those rpms.

 

probably works. I have a zf5 460 410 truck, 65 is pretty nice; 350 gives you 10% and guess what, 65+10% is 72. might be good. torque you probably need t use 4 instead of 5 on passes and towing, but empty 5 would be fine. Mileage might start to creep up to the teens too on freeway trips.

 

It's all good to run the numbers on gears, tire size & speed and all but if you don't know what range the cam works in it is all for nothing.
Smaller heads? Do you want to up the compression? Any 460 heads I have seen have big ports so I don't know what smaller heads are?
Why the change of intake other than to remove weight off the motor.
EFI may help a little in the MPG area but will take along time to pay back.
The 428/460 motors I had it cars & trucks would pull a house down and were used to pull trailers. The truck pulled a 35' 2 car trailer on weekends.
My .02
Dave ----

 

the cam is a Ford police interceptor from about '69 or '70. don't know the specs, I'll have to do some research. it would probably be easier to get a new cam spec'd for truck/rv use.
the SCJ intake is a massive single plane unit. no runners, just a huge open chamber. that can't be good for low end. Weiand has a idle-6800 dual plane that may work. others start at 1500.
I'll have to measure the head intake ports, again they are factory SCJ and low rpm velocity isn't what they do best. depending on the intake manifold chosen maybe I can make some restrictors to jam in them.
I acquired this engine almost 40 years ago to stuff into a '77 F150 4x4, back then bigger & faster meant a lot more than what is the intended use? life changed my priorities and the engine has been collecting dust in the basement for a longggg time. about the current target vehicle, you'll notice my user name is "78 Bronco in pieces". that's another dusty story.

 

You could probably get good money for your 429 scj heads, I guess a lot of mud truck classes require factory steel heads.

To make your combo the best, try these guys;

Parkland Performance Auto Machine - Home

Scotty will fix your right up with a combination that will be exactly what you need, motor wise. Custom cam, curved distributor and basic heads. They do a lot of BBF business. I have had him make me several custom 460 cams, solid rollers and a hydraulic flat tappet cam for my truck. The site has a bunch of useful info too.

Jess

 

I'll throw this out there even tho it doesn't directly relate to your engine or trans. I have two 79 Bronco's I did 460 swaps in (and a third still a 400). These were 89-90 era EFI 460's. I used Price MS adapter and converted to carb on both. One is C6 other is NP435 so no O/D here. Both had 3.50 gears. On the C6 truck I swapped frt and rear axles with a 78 I had with 3.00 gears - apparently not common. The C6 truck with the 3.00 gears is SO much more comfortable at hwy speed. Even with TC slip, feels much "happier". Plenty of take off acceleration too. I have the gears to do the NP435 truck eventually. Not your situation I know, these low-power factory engines may be happier spinning slower than yours would.