dose anyone have experence with 400m im rebuilding the one in my truck and was told it was bored out 40thousands when i first bought it but i think the guy lied but dont know for sure dose any one know how to tell.
The only way to tell if an engine has been bored out is to measure the bore - telescoping guage and a calipers or micrometer is needed.
Take the bare block to a reputable machine shop. They will measure it and check it for what bore it has now, and what it needs to refresh it with the current wear.
You will need to know the stock bore diameter.Then you can get a ballpark(fairly accurate) idea by measuring the diameter of the bore at the deck.If its larger than your stock dimension...you have an over bored block.But to be precise as to bore size,yes, you need to get your hands on a Dial bore guage or a snap guage and a micrometer.good luck
Check out Tim site on this 400, I'm gonna sell it. I have less then 1,000 miles on it. Toooo many other projects! Heck, even make a good deal on 78 150 4x4 shortbed That the engine is in right now! http://www.tmeyerinc.com/400Ford.htm
Sometimes the pistons will be marked .030 or what ever the oversize is. May be marked on top or underneath. Best not to go over a 040 bore unless sonic checked. Best to just buy my engine! hee hee
Fwiw: Stock bore on a 400m is 4.00" They are good to .040" over. You can take them to .060" over, but like dkstuck mentions, you really need it sonic checked to do so. They are notorious for overheating and thin cylinder walls at that overbore if the block was not cast perfectly in production. High volume production of the cast iron parts led to what is called 'core shift'. Core shift is commonplace, but never really made a difference until engine blocks got super thin to save weight and money. The factory still didn't care about core shift though. It only affects the end user way down the line when they rebuild. Core shift didn't affect the engine right away, so the factory didn't care. Therefore they cast the blocks fast, cores shifted all the time, and they still used the blocks. You might have one that shifted. You won't know until you get it checked or build it .060" over and have problems.
thats the thing the pistons dont have any makings on top the only thing there is a big arrow that shows which way the piston gose forward so could they be stock
All oversize piston are not marked. Better measure to be sure. If it is 040 an needs bored, I'd find another block, 351m is the same an cheaper to buy. Take all your stuff an install to your renewed block with what ever work needs done. As PM'd Tim Meyer website is the MAN to talk too! Good Luck, if I can further help, holler
Heres a good 351/400 story for ya. I was in highschool and rebuilding the 351m in my buddies dads Torino. We disassembled and sent out for machining. Found out the crank was no good. Went to the wreckers and got a good used one to machine. Got the parts back and started the re-assembly. Got the crank in and then started on the pistons. No probs till we moved the crank and OOPS the piston popped above the deck. The teacher thought it was funny. Right away he asked where we got the crank. Yep got a 400 crank. Back to the wreckers we go and spent 2 hours finding the pistons/rods and caps. Had to send rods out since caps all mixed up. Never did tell his dad he ended up with a 400. First trip up north we buried the speedo. Talk about young and stupid. 110 + MPH in a sloppy old Torino.
