http://en.wikipedia.org/wiki/Ford_335_engine says "The compression reduced again for 1973 and a new timing set retarded the camshaft timing 6° to aid with reducing emissions."

 

Hmm, so I wonder if this is the case for my 1978 400 engine. I am just deciding what the most economical route to go would be.

 

Yes. Bubba's site (available via the Wayback Machine) says "Beginning in MY 1973, Ford retarded camshaft timing by 6 degrees on all 335-series engines (except the 351C 4V) to meet emission control regulations. Camshaft timing was retarded by changing the keyway offset from the alignment mark on the crankshaft timing sprocket."

The key word is "beginning", meaning it started there and carried on. Your 400 is a 335-series engine and 1978 is after mid-year 1973. So, your cam is retarded 6 degrees is the timing set has not been changed out with an after-market unit as even the Ford replacement units were retarded.

The factory cam is a pretty stout bump-stick, and almost too much cam with the poor compression the engines have. So the biggest bang for the buck is a new timing set, which the engine assuredly already needs. No need to replace the cam itself, just the timing set.

Yes, you can replace the intake manifold and the carb, but if you aren't going to wind it the stock 2bbl works fine. However, that would be the next step after a timing set. And/or a different cam, possibly with less duration.

After that, a rebuild with pistons from Tim with more compression would be in order.

 

So just to confirm, you're stating that my 400 is a 335 engine even though my engine label states that it is a 351/400m 6.6L? The 6.6L is the 400 version.

 

You haven't read anything from the link I gave you, as the opening paragraph says:Note that it doesn't say "351/400m" as you said, but "351M" and "400". Those are two different engines. You can read in that link, which is considered by those that know to be the best reference for the 335-series engine, how the engines were developed. The 400 was always called the "400" since there was no other Ford engine with 400 cubic inches. Later its little brother was created by destroking the crank to 3.5", which gave 351 cubic inches. But Ford already had a 351 cubic inch engine in the form of the 351C so they called this one a 351M.

The engine label is just giving generic info for both the 351M and the 400. It is not saying the engine is a 351M/400 as that is a physical impossibility. It cannot be a 351 cubic inch engine AND a 400 cubic inch engine at the same time. And yes, the 400 is a 6.6 liter engine, with the 351 being a 5.8 liter engine. Simple math as one cubic inch is 61.024 liters.

 

Thanks for the informative response. I didn't see the link originally on my phone, once I get home I will read through it. My mistake.

 

I don't mean to yell or preach, but I'm just trying to help you understand what you have. And I've recently missed links while viewing on my phone, so understand.

 

No issue, I just appreciate all of the help and knowledge. So here's two more questons for you guys:
1. I will get a new timing chain, are there any that you recommend?
2. Without replacing the pistons or increasing the compression ratio, does it make sense to add a new intake and carb? Or should I just stick with stock equipment? If I stick with stock, I would swap my carb from my 351m 5.7 onto the 400 6.6 motor.

Let me know, thanks!

 

There are several good brands. But Tim Meyer, who is the guru of the 400 engines and is active on here, sells them. So I'd give him my business since he provides us so much support. Without him we wouldn't have the piston options we have for that engine.

As for the intake and carb, you haven't said what you are going to do with the truck. But I think a 600 - 650 CFM 4bbl is a good addition, which means you need a new intake manifold. Tim recommends the Weiand 8010, but they've recently switched their production to China and the first batch of intakes are not usable. Tim bought up some of the original US-made ones so may have one for you, but if not I wouldn't buy one from anywhere else as you are likely to get one of the unusable ones. So if you can't find the Weiand I'd go to Edelbrock. I run one of those on an M with an Eddy 1406 and it does well.

 

I will make sure to go through Tim for the Carb and Intake. Here is what I plan on doing to the engine. For now - Get a new timing chain and change out the water pump. I do not plan on changing heads or putting custom pistons on at this point in time, I just can't afford it.

That is why I am debating if it would make sense to get a new intake and Carb. Keep in mind, the 400 engine I have does not have a Carb, so I will be swapping the Carb from my 351m 5.7 engine. In regards to the truck, I already have a solid 1979 Ford but it needs a little body work. I plan on using the truck for 80% road usage and 20% off road / towing.

Hope this helps, thanks!

 

Tim can direct you, even on the intake/carb issue. But, the Motorcraft 2150 carb off the M (it is a 5.7519L, which rounds to 5.8L, not 5.7) will work on the 400. So you wouldn't have to change intake or carb until you go with new pistons, cam, etc.

 

. Tried to answer yesterday, but couldn't reach most websites for a while..


. Yes, any 351M or 400 made after mid 1971 has retarded timing and low compression pistons...


. And the late 1970-early 1971 stock-type flat top pistons no longer available...


. Not sure if the stock timing chain can just be advanced a tooth and work...

 

I plan on replacing the timing chain (I have spoken with Tim) and have one FINAL question. What timing do you believe would be best for the 400 engine? From looking at the links, it looks like the factory is timing chain is retarded *6. Should it be retarded 4, 2 or advanced from 0, 2, or 4?

Thoughts?

 

. I'd advance 2 or 4 degrees... that will close the intake valve sooner and make the engine act like it has a slightly higher compression ratio...

 

I would have said install it straight up. But I don't know so I'd ask Tim - when you call to buy the timing set, or intake, or carb.