My 400 just spit a head gasket and needs a new rear engine seal. I figured while i got it apart id do a little upgrades and build it up. Im looking to do something decent for towing so some low end torque. From my reaserch i believe i want to shoot for the 9:1 compression range and put the timing straight up. Trying to keep costs down. Any thing else i should take into acount? What are some reputable brands for pistons, rings, bearings?

 

Add an RV type cam, springs etc. Pistons and other parts:

https://www.tmeyerinc.com/product/piston-set-ford-400/

 

Maybe your budget is more than I'm thinking but generally speaking You won't keep costs down if replacing pistons on a 400 just to have a good torquey truck motor. For higher compression pistons with the proper pin height you're pretty much limited to TMI, an EBay seller (+/- $500 I believe), or custom pieces....all expensive. Then you have to have the block machined for those new pistons, pistons put on rods, maybe balance rotating assemly, etc. Shop will probably talk you into reconditioning rods, polish crank, etc. You see where I'm going here.
Don't get me wrong, you can build very nice engines out of these, Its just usually expensive to do it. But if it's the original engine or you have a good budget or the pistons are shot then it may certainly be worth doing.
If not then you may see decent gains by installing a "straight up" timing set, good dual plane aluminum intake, 4 barrel carb, long tube headers, and maybe a cam. There's nothing wrong with 8 to 1 compression for a torquey truck motor IF you choose a cam that is designed to work with lower compression. This of course means cams with lower duration numbers such as a Comp 255deh or similar. The Comp XE line seems to "crutch" low compression engines but I feel they're just too aggressive to get any longevity especially in a daily driver type vehicle. You also may experience pinging due to the huge deck clearance of these engines (expensive pistons take care of this).This can usually be corrected with proper timing though. I've actually never had a 400 ping, even when hauling heavy loads. Anyway, good luck with your project and have fun.

 

Budget wise i'm in the $1500 - $2000 range but i also want to do the job right. Engine has never been rebuilt which is why i want to replace the pistons. So if put the timing straight up replace the cam and put a dual plane intake (I already have long tube headers and a 600 cfm holley 4bbl carb) i can go with a stock style piston? If replaced with stock is machining required? If i wanted to go with slightly better than stock quality like a hypereutectic piston would i be able to just "drop in" as replacements?

Thanks for all the info

 

Not sure how many miles on your truck, but if the engine is original, there is wear in the cylinders. You can do a quick and dirty ball hone job and put the old (or new standard) pistons back in it with new rings, but you run the risk of having a real oil burner.

The usual thing is to overbore the engine no more than needed, depending on wear. Once you decide on .020 or .030, or if you ran sand through it, .040, or if you droped washers in it, .060, then you order pistons and the people who do the boring finish the cylinders to fit your pistons.

Good luck with it!

 

85e150 miles on engine is unsure. I picked it up 2 years ago as a replacement for the truck. My suspicions on it being original are only because everything internally has been stock. It currently doesn't burn oil so it may be low miles or has been rebuilt with stock components.

Thanks

 

Generally anytime you replace pistons you need to have the block bored to accept the new pistons/rings. As others have stated the notion of dropping in a new stock size replacement in an old cylinder will probably result in an oil burner. Also your machine shop may want to balance your rotating assembly for new pistons. As I said before basically there are no cheap higher compression pistons for these 400's. Good Piston selection has always been the problem with these. I would at least do a compression test on the cylinders and at least see where you stand. It may be in better shape than you think or it may need everything. Then you could pull the heads and visually inspect cylinders/pistons. One more thing...cam selection needs to be done AFTER you know for sure what your compression ratio will be, depending on what pistons are used. Big cam with too low compression = a gutless pig of a motor.......Little cam with too high compression = a motor that will detonate itself to death.

 

Thanks for all the help guys. Now i know what i need to look for and that further inspections required. Compression test yielded 142 as the highest and 130 as the lowest. Most were at 135. Not bad but not great either.

 

Low compression can be from worn rings or cylinder bore wear but oftentimes it's stuck rings from gum or carbon buildup. A solvent can really help free them up and compression will come back up.

 

Thinking its a combo of both. The engine sat for 5 years prior to me getting it. Going to inspect bore and rings while its apart when i do the rest of the build. Its getting a good cleaning when its apart as there's lots of coolant and oil sludge from the blown head gasket.

Thanks

 

Summit's P/N 5200 cam will work with the stock pistons and valvetrain if you're looking for a low cost cam ($120 for cam and lifters) And it'll wake up that 400.