Hey i own a 79 ford bronco with a 351m and well it is in need of a rebuild, many say with the pistons conecting rods and crank out of a 400 i will have a stroker im shure this qustion has come up many times but reely wouldent it just be a 400? I want a bit more power thats why i am considering this so if it would be a stroer what kind like size wise? and im shure some people are going to say go find a cheap 460 or 429 but i already have a eddlebrock intake and carb and headders and this is going to be a cheap build, 1000 bucks is my budget for this rebuild, what else can i do for more power considering i already need to get all the seals and gaskets bearing and rings within this budget too. what would you do and is a 351m with the crank and pistons and conectiong rods from a 400 just a 400 or a stroker?

 

The 351m/ 400 is called that because they use the exact same block. they both have a 4 inch bore. the 351 has a 3.5 inch stroke while the 400 uses a 4 inch stroke. It would be a little silly to rebuild a 351m if the pistons need to be replaced and the crank needs to be turned because for 400 pistons and finding a used 400 crank to turn would be real easy. If your going to have everything machined then step up to a 400 crank for very little money extra.
If you are just going to put new rings and bearings in it and call it good then stay with the 351. A lot of it depends on what shape the motor is in when you get it apart. This is a good idea when you have another vehicle and this is just a toy. You can take the time and save a little money. If this is a truck you need and depend on it pays to have a plan before you take the truck out of service. If the cylinders dont have a huge lip in the top and the pistons are good and dont have cracks then the block can just be honed and re ringed. As far as the crank goes as long as you had good oil pressure and the bearing show no copper or are in overall good shape then you can get away with a simple crank polish and have the big end rod checked. I know there will be a few guys chime in and say thats no way to rebuild an engine. I agree its not the best but in these tough time sometime you just cant afford to spend 2000 dollars or more to do it perfect. I have done both. put 5 grand in an engine and it lasted forever and put 500 in a rering and it got me buy for 5 more years. this all depends on how much you want to spend and your experience level. I would never suggest a first time engine builder to spend 5000 on his first motor. A simple rering will make you proud. As far as performance goes. This engine is basically a tall deck 351 cleveland, and no one can argue the performance of that screamer. A simple rv cam, headers intake and nice 570 to 650 carb will make 300 hp and 350 torque. And that will get you stuck just as fast as 500hp. If you buy new pistons keep your compression ratio around 9 to 1 and if money allows some roller tip rockers are nice. I know this was a little long winded but i used to build motors for a living and the 351c 351m/400 was my favorite engine. and I guess technically if you put a 400 crank in what was originally a 351m block you have a "stroker" 400. And despite what people say this engine is not a boat anchor. It is true however that for the same weight a 460 will smoke it. But who cares its not always about going fast sometimes its about getting there. 351m/400 is a dependable engine.

Hope this helps

Matt

 

If you want more power get an aftermarket performance timing belt, it CAN'T be OEM, as those trucks came with retarded timing for smog issues when they were designed. I'll try to find a nice article i readed about this, pretty much everything you need to make that engine a monster on a low budget.

 

well its a toy and i could prolly pick up a donor 400 around were i live i know alot of ford fans so prolly under 200 bucks or maby even free never rely thought of turning the crank but i could get a rebuld kit with the pistons and rings for like 310 bucks im going to say 400 after shipping and it incldes the bore so im sitting at 600 bucks then my buddy just got his block bored and squared for 370 bucks yeah that leaves me 30 bucks left but i wanted to see what others thought maby willing to extend my budget like 1500 bucks it is ging to be a cheap rebuild and the shop im doing it myself i will have a mechaninc that builds race engines for mud drags there for questions and to check my work but wen i ask him questions he always tells me to suck it up and get a 460 haha another thing i read is th 400 has good torque and my truck is basical a mudd and dird dtiver never sees much highway and soon never wil again other than town here to there use

 

Are you talking about a nice double roller steel? I have never seen a timing belt conversion kit for a old carbed v8 that did not cost an arm and a leg. Or one for a cleveland at all.
but i agree the factory timing chains were horribly retarded. no offense sara palin

Matt

 

That is usually what i do. Pick up an old running engine. Take my time rebuilding it and drop it in over a weekend. You can never go wrong taking your time. Getting in a hurry will always cost you money. Don't be swayed from your goal or what you want to do. Advice is nice and usually helps but don't let people push you to do something you don't want to. If your local shop will no support you then find another one. People should be happy your getting your hands dirty and not playing video games. but now i am just preaching. It will make plenty of torque and it should be easy to stay under 1500. stick with simple tried and true, headers, cam, carb, intake. you would only need to turn the crank if the old one is worn below spec. 99 percent of the time if the bearings are in good shape the crank will be too. Squaring a deck is kind of a race thing. It is not needed unless the deck is warped. This is rare on these blocks. they had a lot of metal in them and thats why they are so heavy. If the head gaskets are not blown when you tear down the donor then there is no need to deck it. and as far as boring the block also not needed if there is not a bad lip. if this is going to be a toy it will never see 20k miles. No point in building it to last 30 years.

 

There are some articles there... not the one i mentioned, but well...

https://www.ford-trucks.com/forums/5...-and-400s.html

 

thanks for the info and the shop, he is suporting he he just swears by 429s and 460s he has a 73 ford its got a 460 a 78 with a 460 and both are mildly done up his son has a bronco simmilar to mine and im good friends with him he has a done up 460 in it and has a project short box thnk its a 77 hs buildng a 429 for it and this guy his race truck for mud drags is a 79 bronco and the block he used was a 429 super cobra jet he swears by 460s i swear,haha hes just giving me a hard time i got a 351m in my truck it needs a complete reuild it burns oil leaks oil and just recietly has a ticking noise i am just going to get the donor crank and conecting rods and use my 351 i think but i guess is hard to say what i am going to do expecialy with that tick but still info for cheap ideas for hp and torque ill be apreciatd thanks everyone

 

FWIW, there are no performance pistons for the 351m or so I've seen said here and in links about the engine.

400 crank
Flat top pistons for 9.5 CR
RV or your other choice of cam
Springs to match
Aftermarket "straight up" timing set. (always sprockets and chain)
Your intake, carb and headers.
Fiddle with the heads if you wish.

WELL into 200, possibly 300s hp wise, and should have a broad torque curve as well.

No free advice, but he sells parts, and has a catalog on line with the pistons you might could want on page 18:

TMeyer, Inc. Precision Automotive Machining