yea the 351m/400 where plagued by the emission ****'s of that era. had that motor come in the mid-late 60's it would have produced far better.

 

its a 78' 300. so keeping the stock carb/intake and all that is the way to go? i have to put a new exhaust on before june inspection so was just wondering. and the exhaust has a REAL strong gas smell so i'm prety sure its burning a little ritch. as far as i know it has no emission equiptment on it.

 

302! "Mouse engine, Gear'd down, dreaming of pulling a Freight train!"
3xx V-8's: "Any number of white Mice on a treadmill dreaming of Big Black Rats on a Treadmill"

The 460; "is the large well fed herd of Big Black Wharf Rats on a Treadmill!"

 

302! "Mouse engine, Gear'd down, dreaming of pulling a Freight train!"
3xx V-8's: "Any number of white Mice on a treadmill dreaming of Big Black Rats on a Treadmill"

The 460; "is the large herd of well fed Big Black Wharf Rats on a Treadmill!"

 

The 400 is worth the money and time! I own a 80 F150 4.9 300 installed w/3spd granny low bone stock engine, and my buddy has a 79 F150 with a 400 w/ I believe T19 3spd granny low w/ intake a 750cfm carb. I've driven them both and pulled with both and the 400 takes the cake ALL day! There are issues with perches and motor mounts but a pretty easy job in all. We are currently working on a 67 Bronco, and guess what putting another 400 in it! If your looking for perches and mounts bronco graveyard sells em!

 

I mean 4200rpm. It was about 32-3500 stock. I dont normally take it that high, but I had to see what it would do. If I'm smashing the pedal, I shift around 3800. My nephew's built 300(the one on youtube "ford 300, cam") goes to 5200. His will shift around 4400, with a C6. Just my opinion, but a 300 with a turbo, would be the ultimate street engine. It's only money!
As mentioned, the 400 needs help to wake up. For what it cost to get 300hp from a 300, you could have a 500hp 390, 400, or 460....or 400hp diesel, but that's another story.

 

Just because it goes that high doesn't mean there is any power up there. Mine goes to 4,000 with ease but doesn't make anything but noise. A stock 300 has no real power past 3,200 rpm.

I agree with you. A turbo'd 300 would be awesome for a street machine and DD.

 

what do you all think the best set up is for a the 300? (carb/intake/exhaust) some say all stock some say 4 bbl w/ headers?
and can you adjust the fuel/air ratio on a stock carb on a 78' 300? its def burning ritch.

 

All those exotic Cam's and Intakes will turn your 300 into a Weed eater.
Note the lowly weed eater has to run at some phenominal Rpms to have any power at all.

The 300 works best as it came from the Factory. Pour lots of money into it and you still dont have what a guy could get with a stock 460.

The 400 had that possibility of a slow speed, super torque'er! Somehow it never developed that way.
Those of you that have driven the venerable John Deere 320-T, a twin cylinder that idles and works at 2500 Rpm know what Torque is without Rpm.
I thought the 400 would be like that , but nope, it aint no different than a 3XX. Just another smooth running engine.

 

You may be suffering from somebody's 'alteration' of the main jet. Maybe trying to get more HP out of it.
See if you can find a Carb kit that comes with a main jet.

Careful of the stuff you buy in a junk yard. That Carb was used on several engines and lots of carbs look the same. However that main jet can be smaller or larger.
Get the right one for your engine and you'll have done the best you can.

 

The little six is a good eng pound for pound more torque than a V-8 but if you want a racing eng heres what you do to the 400 the guys are right with its low compresson 7.9 to 1 this was done for emissons lower compresson ratios produce higher exhaust tempatures. since there are no upgrades for a 400 have a machine shop pin fit pistons from a 351 it bumps it up to roughly 9.5 to 1 to figure out the compression ratio you have to be good at math it might as well be rocket science to me so thats why I say roughly 9.5 to1 . I also went with the meanest cam I dared try. upgraded valve springs If I remember correctly it goes pretty much like this Stock, RV cam, then the next size up and then about then anything bigger it becomes to difficult to run for normal use you get into needing to much stall if your using an auto and drivabilty problems for everday use cam selecton is critcal dont overdue it . the 400 I put together I used was the next step past RV cam and it was recommended to use headers anyhow that 400 is a monster it doesnt shake the ground like a 429 but it's close lots of torque at 2000 to 3000 RPM and not much sense in spinning much faster but a heck of an eng when you tweak em. SO stick with the 300 six they kick butt unless you want to spend lot of $

 

The Dirt track guys use this as a rule for Cam's.
It still has to pull 22" of vacuam at 1000 Rpm. Using that as a rule, it will still start when hot with the standard Stock starter.

So the Cam you buy for the street should fit that mold. Ask your cam supplier about which cam?

I sure didnt know about fitting new pistons. Back in 58 I put a cam in a guys 57 Chev V-8. I imediatly bent all his valves. Ignorance on my part. I never dreamed he'd also need some Pistons with Fly cuts so the valves had room to open at high speed.
If you have to put new pistons in your 400 how would you know???

 

I'm abou to pull my dad's Elky on a car hauler. It should be a combined weight of roughly 5,500 lbs. I'll let you guys know how my 300 handles the job going thru town, stop and go.

 

I used to pull a 7200# boat with my bone stock 300 (78 F-150 4X4) with no problems except going up those mountain passes.