Rebuild a 400 verses a 460 motor?

[chapmad1]

I have a 1978 Bronco XLT which I am parting out (listed in the classifieds broncograveyard.com). I am planning to keep the motor, drivetrain, and axles to swap into a 2003 Jeep TJ. The TJ will become a beefy daily driver, with a rock crawling suspension. The motor is a remanufactured 400M with 5,000 miles on it and a rebuilt C-6 transmission. The truck runs, but has only been started occasionally since the rebuild (to keep it mobile) for the last 10 years. It is very sluggish now with limited brakes, I assume from a major vacuum leak. I plan on having a shop go through the 400 to refresh it. I also have plans for cams, intakes, etc to increase horsepower.

My questions to the Ford enthusiasts out there are:

1) Would I be better off finding a 460 and putting the money into that instead? Most threads indicate the 400 was a poorly designed dog…..

2) Should I dump the C-6 in favor of a better transmission, maybe a manual?

Thanks for helping out, Dan

 

[Rons beast]

Hey Chap, welcome.

It's difficult to answer your question, since what you want to do with the truck, is 2 things that are polar opposite.

For a daily driver the 400 is better, with the C-6...... Not the best for a Rock Crawler.

The 460 will have much more touque, and be great bolted to a strong man. trans.....Lousy to be driving daily.

The rock crawler needs higher torque and horspower, low gearing and a tall articulating suspension. BIG tires... All are killers on gas milage......wouldn't want to have that as my daily driver.

You may want to rethink your plans.

Good Luck with whatever you choose.

 

[Bully Bob]

Hi Dan..,

What Ron said but I would add;

It sounds like you don't intend to "rock" this rig but run the streets & "impress the ladies"..!! Nothing wrong with that..., but a very expensive way to accomplish your goal.

"I am planning to keep the motor, drivetrain, and axles to swap into a 2003 Jeep TJ. The TJ will become a beefy daily driver"

Whichever motor you stuff into this 'lil Jeep, the motor won't even know it's dragging the Jeep along. What you're planning, at the end of the day, is not a safe vehicle for the street. You could be hurt, or worse, hurt someone else..!!

Call Currie Ent. They put a big-block in a Jeep. They could advise on the headaches.

As to rock crawling.., some time back a Suzuki Samurai nearly won the "Top Truck Challange" with a 4 banger..!! He lost only because his side-kick got the winch cable wrapped 'round the front wheel in the mudhole. Otherwise, he would have won.

He had all the other "heavy iron" rigs beat 'til then.

Point being, you don't need mega-engines to rock crawl.

Just say'n........

 

[chapmad1]

Thanks for the replies!.... Let me clarify more. When I say "daily driver" I really mean a street drivable vehicle. It would be for driving back and forth to trails, for fun, or for shows. My last jeep was a CJ7 with a stealth 360 in it and only 2wd, hotttt, and it kind of spoiled me. My new rig will probably be turning 40" tires on an extended wheelbase from crawl speed to 75mph on the highway.

About to tear into the 400, but contemplateing just cashing it in for a 460....?

PS. Gas milage isn't an issue. I have been driving a Honda Insight that gets 60mpg for 13 years now to save up for this project

Keep the thoughts coming! Thanks a bunch, Dan

 

[Bully Bob]

"My new rig will probably be turning 40" tires on an extended wheelbase from crawl speed to 75mph on the highway"

My point exactly..! [-X

---Over-n-out on this post---

 

[miesk5]

yo chap,

WELCOME!

Here is some info for you;

351M/400M Workshop; EXCELLENT M Block Information Source

Source: by Bubba (Dave R) at http://grantorinosport.org/BubbaF250/index.html

He includes sections such as;

Enhancing your stock M-block

Other than the obvious tune-up, what else can you do to get the most power from a stock 351M or 400?

Building a more powerful M-block

If you’re going to rebuild an M-block, what can you do to get a significant improvement over the stock power output, without breaking the bank or re-financing the house?

Rotating Assembly Considerations

Don’t you wish somebody made higher-compression pistons for the M-block 400, or are you using the best (or correct) crankshaft and rod bearings?

MUCH MORE~

===

351M/ 400M Rebuild or Should I Swap in a 429/460? in 78-79

Source: by Paul E at http://www.projectbronco.com/Technical_Articles/should_I_Keep_it.htm

Paul includes Links to;

"How to Build a 351M/400" http://www.projectbronco.com/Technical_Articles/351m400_performance_build_up.htm

"Installing a 429/460 -- The Right Way!" http://www.projectbronco.com/Technical_Articles/installing_460.htm

351M/400M to 429/460 Parts List

Source: by Trent (Picador, a Four Door 79, InfoFord) at http://www.ncspecialties.com/autobody/460/index.htm

351M/ 400M to 429-460 in a 78

Source: by Monster MAFIA Offroad at http://web.archive.org/web/20050228122329/www.angelfire.com/wv/fordbroncos/engine.html

 

[chapmad1]

Thanks to all for their input in this discussion. Thanks especially to miesk5 for his links, saved me a lot of time!

Lots of reading, researching, and pricing! I decided I would trade the 400 in for a 460. Although the 400 can be built up, there is more support and aftermarket parts for the 460, and the dollars per horsepower were better. I settled on a rebuilt 460 with aluminum heads and a mild cam... somewhere around 500hp. The aluminum heads and aluminum intake should make the BB about the same weight as a stock 400M.

Now the fun begins, fitting it all in and building a full suspension!

Thanks for all of the help! Dan