Right now Ive got a 78 F-250 SuperCab 4x4 with a 400. When I got it the motor had a bad cam. I was going to build a 460 for it but I came across a parts truck with an overhauled 400. I pulled that motor and dropped in a Comp XE256 cam. It still has the stock exhaust and 2bbl. Ive never been a big fan of the 400 but I figured this would be a good opportunity to have a decnt motor at a cheap price.
Now that Ive got my tuck running I am just not happy with the performance of this 400 and it just doesnt seem to want to tune properly plus theres some sort of rattle noise when I give it a certain amount of throttle. Before I go spend money on a 4bbl intake and good carb with electric choke and headers and good flowing exhaust I just wanted to see if anyone else has been in this situation. Is it worth messing with this 400 or am I better off building a 460?

 

the 400 can be made into a real screamer with the right parts selection and build. it is one of Fords overlooked engines because there was never much of a following or aftermarket support for these engines. remember it is a realtion to the 351 clevelend engine so most parts will interchange. and the aftermarket is starting to catch up to the 335 engine family finally. Edelbrock just came out with aluminum heads, there is the CHI heads that are suppose to be incredible, a few Aussie performance heads, the Aussie factory heads and of course the 4V clevelend heads that help the engine breathe and live up to its potential.

the main thing with the 400 is that they had little to no factory performance backup and had pathetic compression numbers (unless you get one of the early I think 71 motors that had 9:1 compression) most had a whimpy 8:1.

so the 400 can be built into a nice performing engine but needs help.

but of course the 460 has a lot more potential and aftermarket support. and then there is the old saying, there is no replacement for displacement.

so on one hand the 400 has lots of potential, it will just cost more to get to that point where as the 460 has huge potential and won't cost as much to find it.

kinda of sounds like you had your heart set on a 460 from the start, so i think you already now the correct answer to your question.

rgds
Mike

 

With my 400 it wouldnt take much money to improve it with an intake, 4bbl, headers or even a good set of heads compared to building a 460 from scratch and making it fit in my truck with the L&L kit. My big concern is overall value. Im not too committed to my 400 financially so far but if I fork over a few bucks for upgrades I will be past the point of no return and I dont want to be disapointed. Im not so sure the extra 60ci is worth it overall either. Im at a crossroad of weighing my options right now. Hopefully other guys will offer their opinions.

 

Hello, I have a mild 400 with aftermarket intake and carb. No headers but a dual exhaust with a cross over. I did a rebuild with a rv type cam and the straight up timing chain. It is in a F350 with a lincoln welder and a custom welding bed on the back and I have towed a skid loader a couple of hundred miles with it. I have been very happy overall with 400.

 

there are 5 main players in making power (yeah i know power is freed up in alot more places but these are very major) and the 400 only came with 2 from the factory

carb-only a 2bbl factory intake and carb
cam-hahah yeah right
compression-again, a joke from the factory
cubic inches-now were talking...400ci is a good place to start
cylinder heads-the stock heads flow almost exactly the same numbers as the gt40 heads, so these are almost a performance piece except they are opened chambered design.

 

Be disappointed... The thing only has a 2V carb and intake! Don't compare apples to oranges here. And do you know if the specs of the cam you put in match the compression ratio of the truck, and maybe the truck needs a higher stall converter? Too many variables. Be very careful when buying someone's rebuild, and take some parts off and see what it has, and definitely check the heads and valve geometry...
Check out the price of building a 460 vs. messing with what you have now. You might find the 400 much more attractive then.

 

I had a fullsize Bronco with a Ford 400. I pulled it and was going to put it in a 1966 f100, but I also had a 460 available. after talking with a few performance shops, I was basically told to go with the 460, hands down. Whether you are planning on buiding a go fast motor, pulling motor or just a strong daily driver, the 460 has much greater potential, and parts availability to boot. I never did do the swap, but I now have a 1996 F250 Supercab 4x4 with a 460, and even in this huge truck, performance wise, it would bury that Bronco with the 400. Good luck. Ted

 

with a few of the right parts that 400 will run very well , but agree you can't replace cubic inches..

 

No, you can't replace cubic inches, but you can sure save a lot of money fixing up a good -running motor vs. buying and building a completely different engine, plus all the work it will take to convert it to the 385 series...

I am trying to be realistic, and the 400 is still a solid engine to have to 'settle for'...

 

I had a 400 in my truck for a number of years. It was newly rebuilt then I also put on an Edelbrock intake, cam kit, Holley carb, headers, dual exhaust. etc. I blew it up in the mud and decided to put in the old stock 460 I had lying around, I put a new Edelbrock intake, my old carb, and L&L headers and the difference was night and day. If you don't mind spending the money and time to swap one in it will be well worth it. At least it was in my experience.

 

I still had a stock intake on my 460, but threw on an Edelbrock carb... The power still wasn't where I thought it would be... (straight up timing set)
Great compression. Maybe the intake would open it up more?

 

Thanks for the input. I think Im gonna get a 4bbl intake and throw some headers on and give the 400 a second chance. I drove the truck a lot over Thanksgiving weekend and it ran good...not great just good. I havent been too impressed with the 2bbl...it seems to be running rich and when I put the truck in gear it tries to die.

 

Sounds like it might need a fresh rebuild... I still have the factory 2V on my '78, and it has run perfectly since new, so I haven't had to mess with it...

The 4V intake and carb should help with your mileage too, as a bonus side effect! (smaller primaries)

 

the 400 is a good motor with the right parts. Do you want to spend a little on a slight bigger version of the SB. or blow a lot of coin on a 460 BB. They best part of the 351c/m and 400 is they share the BB bellhousing pattern

 

Actually the 351C has the small bellhousing pattern...

The 400 and the 460 are both great motors with the right parts, but when you already have a fresh 400 or a 460, why switch from one to the other? Make the most of what you got is what I say! (although some folks here have enough money to put a 460 in everything they buy)