First off, Im new to the scene but have been reading several threads and have found some very good info.

So... My wife broke her 79 F-250 out deer hunting a few weeks ago. I took the engine out and found it dropped a valve. No biggie really, Ive been wanting to rebuild this thing since she bought it. We knew it had been gone through before. It has an Edlebrock/Weber on it with a performer manifold and headers. It sounded like it has a mild cam. Now that i found the valve munched a piston alittle and the fact i wasnt very happy with how it ran, I get to do this MY way lol. Well, not EXACTLY my way. If i had my way, Id be doing an LS swap ou of this 400M but, here we are. Ive been looking at many builds and have decided what way were going with this. We definitely want to keep the torque down low where it belongs so a roller cam is going do this for me. Ive contacted TMeyer about a package but since this has already been gone through once, I found that were already .030 over so will be going .060 over. Problem is, without stepping on any toes, is that the only place i can get decent pistons for this 400? He is out of stock on anything but .050 slugs. The machine shop is telling me were going to have to go .060 over. We want to stay right around 9:1 ish. I know this will be a huge improvement over the 7.8:1 ford thought would be ok. While were not in a huge hurry to get this done, id like to get this done. Thanks in advance for any replies!

 

Curious as to why it has to be .060 over. Did they give you any details about it? Is it because of wear or if the valve scarred the cylinder.

 

It was punched .030 over on a previous build. The machinist just told me we needed to go another .030 for a total of .060 due to wear and a little taper in 3 cylinders. Luckily, we can save the head that broke a guide when the valve stem was bent to a 30 degree angle when it dropped.

 

Remember the golden rule: any auto can be cool as long as it doesn't have a LS or SR powering it.

Regarding the 400 block in general. They are not a thick walled, over-built blocks by any means. A .030 over on a thin walled block is usually max and its time to find a different standard bore block to start with. I look for a 4" bore & 4" stroke as a perfect starting point. But the ford 400 block is not a wonderful block, like a lsx block.

 

I'd think really hard before building a .060 over 400. I had one once - always seemed to run a little warm for my liking. Once I discovered it had .060 over pistons in it (chasing another problem) - had enough experienced/old timers tell me that was too much for 400 block and why cooling was an issue, made a believer outa me.

 

Check the local lakes, lots of 351ms at the end of chains. Or anywhere you find a 351m or 400. Why risk a weak cylinder wall?

 

No such thing as a 400M, it's just plain 'ol 400.

 

Just got done dealing with this ford guru that has more ford trucks,bronco's, and ranchero's then I have ever seen. In a trade I got his just rebuilt 5000 mile high dollar .030 over built 400 that "never ran right".
When I took 3 400 blocks to the machine shop in the hopes one was worth building. The machine shop checked the .030 5000 mile high dollar built 400 block they found a couple cylinders to be so thin that they said it was going to have heating problems till a major failure, sooner then latter. The shop said starting with a standard bore block is the way to go. Ended up keeping the heads off that engine.

Another 400 trait - 1 in 10,000 blocks have cam bore holes that are not what they should be. One cam bore hole will be .005 too big and the fix is to send one cam bearing to a coating shop in Eugene. The shop leaves the bearing in a solution for 5 hours while it adds .005 metal to the bearing so it will fit the 400 block. Take a wild guess how I know this?
The coating shop closes for 2 weeks a year to clean out the tanks. Take another guess when my cam bearing was sent to them?

 

Mitch, your machinist should recommend to sonic check the block before boring.

If he did not, you need to find a new machinist.

 

Thanks for the input guys. I was a bit skeptical about going .060 over a well and I did question the cooling capability going that far over. He assured me it wouldn’t be an issue but I think I’ll do some looking around and see if I can’t find Virgin to deflower. The original question still remains. Ishere another source for good pistons for these things?

 

Custom pistons, maybe a Mopar 340 piston. The old Hot Rod mag article used something like that. Let me see....

https://www.hotrod.com/articles/hrdp...-engine-build/

Never mind. They used Chevy rods, had to go .040 over to use the 340 pistons, and needed a serious balance job to make it work.

You could spend a day or two looking for 4" pistons that might work via a different rod or bushing. $$$ for machine work.

Serving suggestion: Find a decent block, go back to TMI.

 

I saw that build. Pretty cool. I’d do it if I had hot rods money lol

 

Out of curiosity, tmeyer pistons run a thin ring really close to the top rendering not that good of a choice for a truck, or low end vehicle, also his stuff is really light, affecting the low rpm torque ASK ME HOW I KNOW. For the cost of that piston kit, why not go stock slugs and mic the crank, if you have any means of grinding or shipping the crank, it won't be cheap, but maybe cheaper than those expensive slugs, and have it ground, but offset grind it 0.020 or 0.030 and that would give you your compression target, as well as more stroke, as well as the heavier and better balanced stock pistons. I built a ttmeyer 400 several years ago. That ring gap and lighrt piston is not the answer I promise. I will not build another tmeyer kit. I love my 400 but that piston choice was a bad one. the roller cam will be fun. do the tmeyer oil mod. I would say use cleveland pistons, bush the rods like the 390 had and use the smaller wrist pin if grinding the crank isout of the question.

 

Do you still have one of those old tmeyer piston with thin rings? Would love to see how it compares to what is being sold now.

Never seen any hotrod articles about 340 stuff but I have some stuff that is really odd for a extreme 400 build and not sure what it is. Should try to dig it out and take a picture tomorrow.

 

no I don't think so, those pistons are the same as the current offerings to my knowlege. The cleveland pistons will bump the CR but run smaller wrist pins so the rods are to be bushed.