well, i was gonna stay out of this one but with all the 400 trashing, i just thought id throw in my two cents. i currently drive a 79 f-150 with a 400, and an 83 f-250 with a 429 (close enough to a 460) the 400 is mostly stock internally except for the .040 overbore and the lightly ported heads. it also has an edelbrock 4 barrel intake and a carter 600...beyond that, just cheap "bolt ons" like an air filter, etc. the 429 is also mostly stock internally but it does have a decent cam, straight up timing, and more heavily ported heads. i figure things are pretty even because the compresion is almost identical, both have 4 barrels, and the trucks weigh in about the same. the only big difference other than the cams, is the 4.10's with the 400 and the 3.55's with the 429. ok ok, enough about the details and on to the performance. as is, i would definitely have to say that the 400 has more grunt off the line and better low end throttle response...and thats after attempting to take into account the lower gears and stock cam. however the 429 definitely takes the cake for mid and high end power, plus it wraps out to a higher rpm than the 400 and has a wider power band. (ive yet to get a friend to drive one so the two can race and settle it) =) anyway, i dare say that if the 400 had the same cam, straight up timing, and heavier port work, it would be extremely close between the two in the area of performance. on the other hand...i can feel the potential in the 429 and am guessing that a good ignition system, intake and carb, and headers and exhaust would really wake it up. who knows how much more i could easily get from the 400. on to the gas milage... the 400 gets 9.5 mpg ALL the time...maybe with higher gears it would do better on the highway. im still trying to figure out a good average for the milage on the 429, at one point i couldve sworn it was getting 12 mpg on a highway trip just by watching the gage, wheras in hard city driving ive seen it drop to the area of 5 or so. after a fillup and doing the math, it adds up to anywhere between 7-10. (like i said, im still trying to figure it out.) to sum it up, the big block will always make more power if compared on a level playing field but the differences usually arent DRASTIC. also, a 400, in my experience, is extremely reliable and not a "peice of trash" or fords biggest production mistake ever. well those are just some of my observations based on experience and theres no arguing with that.

if you were asking this because you were looking at whether you should swap in a big block or rebuild and build your 400, i would say....do what i did, keep one of each! =) ok not really. but just know this, i completely redid my 400 for for ~500 bucks and thats including everything (i was stupid and used stock replacement pistons, cam, and timing set but couldve had better stuff for almost the same price.) if you shop around for the cheapest parts and only get the machining REQUIRED, then you dont have to spend a few grand on a rebuild. (ie. if the heads are in pretty good shape, just polishing up the valves and hand lapping them in rather than paying a couple hundred on new valves, guides, three angle valve job, etc...) ok im rambling now. it just all depends where you want to go with it. good luck.

 

thanks alot,

Thats the kind of answer that I was looking for. As of right now I'm thinking that it would cost quite a bit more and take alot more time to go with the 460. I think first I will do a compresion test and see what those numbers come out like?, mabey a new cam and intake and 4 barrel card combo would be a good thing. The engine already has rebuilt heads on it and new top end dynomax dual exhaust.

So I'll keep you all posted and let you know how it goes.

Thanks again,

Joe

 

Joe, a compression check is a good idea. how is the oil pressure in the 400? if the oil pressure is still good (a rarity on a high milage 335 series) and the compression check turns out good, i would strongly suggest just beefing up the 400, especially since it has a fresh set of heads. again, it all goes back to how far you want to go, but it sounds like youre just looking for a bit more oompph. youre right, a 460 swap can get pricey and time consuming after all is said and done, and especially if you dont already have a big block waiting to be dropped into something...the 400 mods sounds like the more cost effective and easiest way to go. it might be a bigger hassle (especially if the compression is good and cylinder work isnt needed) but i would HIGHLY recommend a set of aftermarket pistons to get you in the area of 9.5:1 compression. if youre not gonna pull the engine though, you can still see decent gains by just putting in a new cam, a straight up timing set, and a 4 barrel intake and carb. you could pull the radiator, grille, etc. and change the cam with the engine still in the truck and swap over to a 4 barrel system all in one weekend of hard work if youre fast. you could do that for under $500 and i would bet with that exhaust and the fresh heads, it would be putting out more than a stock smog era 460. and i almost feel stupid referring to the hot rod build up since its been talked about over and over, but add the pistons, some mild head porting, and some ignition upgrades and youre looking at almost 400 hp and just under 500lb\ft of torque. anyway, im rambling again, but let us know how the compression check turns out and what your oil pressure is like.

 

self correction- the M series isnt 335, its been a long day, i dont know where that came from

 

DAMNT! it really HAS been a long day, the M series IS 335...i dont know where THAT came from. lol