Guys, thinking of getting a rebuilt 400 engine to put into my 1977 F250. I would like good torque as low in the powerband as possible. I came across a company Carolina Machine Engine, which looks like are very reasonable in terms of cost. My thought was that I would invest in Aluminum Heads (Edelbrock) and a roller cam. Obviously both drive up cost of the build, but this is an engine/truck that I will keep for many years. I believe that the roller cam will improve reliability and torque. I am less certain about aluminum heads hear that they warp easier if they get too hot, and not sure if they add much on the low end of the power band. Anyone have any thoughts?

 

First, you need to consider getting the engine from Tim Meyer: http://www.tmeyerinc.com. He is the #1 guy on these engines, and can spec the engine to give you what you want in power, from low-end torque to high-end HP. And, if anyone is building a 400 and doesn't use Tim's pistons then I'd walk away from them. Tim has the only pistons available that give a reasonable compression ratio for these engines. All other pistons are simply re-builder units that will give about 8:1 compression.

Compression is the missing ingredient on the 400's, and 351M's for that matter. With an iron head you can push them to about 9.5:1, depending on the cam and other aspects, and gain significant power. But with an aluminum head you can go to ~10.5:1 and still run pump gas. However, unless that company is using Tim's pistons the CR is going to be 8:1 and you are wasting the potential of the engine and the aluminum heads.

As for the cam, a roller does three things. First, it does give longevity, or at least a better chance at it. Second, it reduces the friction in the engine significantly. Third, it allows the cam grinder to use a more radical profile, meaning faster opening and closing ramps. But, all of that comes at quite a price.

Now, let's talk about the engine for Dad's truck. I talked to Tim and he convinced me to go with aluminum heads since I wanted tractor-like low end torque as well as good economy. That allowed the CR to be bumped to 10.5:1, which will help both power and economy. But, when I asked about the Edelbrock heads he said he prefers the Trick Flow units. Then we talked about the cam. He has several personal grinds that he has Comp Cams grind, and tailored one of those to my desires. So, I went full roller, meaning roller lifters and rockers. And I bought all of the parts from Tim, including intake and carb.

Oh yes, and don't miss the oiling system mod's. Tim has some that significantly improve the oil pressure, which is one of the problems with these engines. According to Tim, with the mod's the engine will idle at 40 psi. But, I know that without the mod's both of mine idled at 10-12 psi.

I had the machine work done locally and don't yet have the engine together. But, I wish I'd just have shipped my block, crank, and rods to him and had him build it. Then he could have put it on the dyno and confirmed what he's assured me it'll give - 500+ ft lbs and close to 500 HP, all at low RPM.

 

Joel,

If cost is no option - go with aluminum heads. I think a roller cam is a great idea on all but the most budget conscious builds. Tim is the man for these engines and that's no lie! He can get you anything you'll need, reasonable prices and great service. The stock type pistons have to go and he can hook you up there too.

Are you running a stock engine now?

 

Thanks for the replies. Yes the engine is stock now. I am looking for upgrading to support towing. It has a 4.10 rear and NP435 4 speed so I think it should do pretty well if I get the engine warmed up a little.

 

Just don't do stock compression ratio and aluminum heads.

 

"I have heard" - the three most dangerous words

I'd venture to say that more than 95% of all new engines sold in the USA have aluminum heads and they have to be certified to meet emissions for 100K miles or more. If aluminum heads were really a warping problem either we would have heard about it by now or the new cars would be running iron heads.

I second TMI as your source for 351M/400 engine science. This is truly the forgotten engine, although 400s won Enginemasters two times running, the average guy doesn't know the first thing. Get a good flowing head and you don't need a big duration cam. Cut down on the duration and you have a much torquier engine at low speeds. So whoever specs the heads should spec the camshaft too.

R.