Aftr watching my friends 79 f-150 work, I'm starting to think the 400 could use a rebuild. My friends 79' has a rebuilt 390 with around 20k on it. 38 inch tsl's, and only 3.50 gears. He can smoke the tires very easily. I on the other hand have a 77' f-150 with a 400 and 33's. I can't even power braek it. Now, I hope I'm not coming across wrong, I'm not wanting a muscle truck or something to just peel out in. I just think that the old 400 ought to have a great deal more power than it does.

Is this a sign a rebuild is in my future? Should I expect more power than I have now? Should a good running 400 have more power than a 390? Where can I find a good rebuilt motor without paying over a grand? I've seen 400's go for around 500 bucks thats been rebuilt. Juyst never seen any local and have no clue where to look. Any suggestions or opinions?

Thanks in advance for all tips/advice!

Kyle

 

that sounds about right for a 77 400. a $500 rebuild will be about the same power output-wise, and may not last very long? the 77 suffers from low compression, retarded cam timing and the 1975 smog head. if you do rebuild, you have to address these issues or you'll just be duplicating what you have now.

 

I gotta ask, what mods has your friend done to his engine? You say a rebuild, but is it a stock rebuild?

I can't power break my '79 1-ton 4x4 with the stock 400, then again, I don't believe I have ever tried...haven't really wanted to, it has 33's as well.

Anyway, you would probably be further ahead putting your $500 into your current engine, IMO. Get an aftermarket timing chain, as stockers were retarded....even going with a somewhat mild, MILD, cam and matching valve springs would help as well. Add some headers and a better exhaust. I would say you should be able to do this for about $500 if you can do the work yourself.

If the engine has high miles or any sort of knocking sound or anything, I would say it's time for a rebuild. As for a $500 rebuild, I don't know who would offer such an engine or if I would even want a $500 rebuilt engine. You can't even get your machining done for that amount, from my experience anyway. I priced out a decent budget rebuild for my 400 in my '79 and got to around $1500 total. I would say that is fairly reasonable. Now, the 400 in my '53, that is a different story. By the time all was said and done, I was well more than double that, but that included all the MSD goodies and a good chunk of machine work.

Good luck.

 

Looks like I need to dump some money into the old 400. I think the double roller timing chain, and setting the timing to straight up is self explanatory. But, how do I go about choosing a cam??? I do not care about mileage. I'm looking for power. Doing these 2 thigns.. will they make a noticeable difference?

 

I put a 400 in my 79 f250 supercab last summer.Got about 2,500 dollars in it.Thats with all the fixings.Got it from jasper(crate engine).I can smoke the tires from on this baby.
Bob

 

sure a cam will make a big difference, but too much cam won't be an improvement. it's real easy to overcam a 335 engine and make it a dog.

 

That's why I suggested a MILD cam.

If you want my opinion, and you want some gains from not too much $$$$, I would put on some headers, a free flowing exhaust (Flowmaster muffler), K&N air filter assembly, and change to an aftermarket timing chain and time it straight up.

On my '79, I installed a K&N air filter assembly and Flowmaster muffler. Just from those mods I noticed slight performance gains in daily driving. I had to actually lean out the carb some after those adjustments as well. If I were to install headers, I think that would help as well. As for the timing chain, who knows. I would do it just because of the mileage on the stocker and some say you will see some performance gains, others say no. I've read where changing that out will help with a little more bottom end, torque. Some will debate me on the K&N assembly, but I'm speaking from experience, that in combination with the Flowmaster was deffinately noticeable.

If I didn't have much money to spend, but had some money, that is what I would do to get me by for a year or two until I could save up enough money for a good rebuild.
On a rebuild, your gains will come from increasing the compression, going to a good aftermarket cam, changing the intake and carb, and exhaust upgrades.

Just my 2 cents