First Things to Do to a 400
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Joined: Mar 2021
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First Things to Do to a 400
I'm purchasing a remanufactured 400 for my 1978 f150. I've heard that these engines are pretty sluggish with all the smog restrictions and such. But, I don't want to make the mods to go up to a 460. What would be some of the first things you would do to a 400 to gain some horsepower and torque. This is a project for my daughter and I. We aren't looking to get 500hp or anything, just a fun daily driver.
This is the engine I'm considering. Mabbco offers a handful of upgrades. What are your thoughts on those as well?
https://www.mabbcomotors.com/catalog...ited-warranty/
They also offer this one for considerably less, it requires a core (which I could do, and I'm in driving distance) but they don't offer near as many add-ons.
https://www.mabbcomotors.com/catalog...ock-1975-1982/
Thanks in advance.
1978 F-150
351M (currently, but dead)
Manual Transmission
4x4
This is the engine I'm considering. Mabbco offers a handful of upgrades. What are your thoughts on those as well?
https://www.mabbcomotors.com/catalog...ited-warranty/
They also offer this one for considerably less, it requires a core (which I could do, and I'm in driving distance) but they don't offer near as many add-ons.
https://www.mabbcomotors.com/catalog...ock-1975-1982/
Thanks in advance.
1978 F-150
351M (currently, but dead)
Manual Transmission
4x4
Grumpy goat
Joined: May 2017
Posts: 3,058
Likes: 594
Can you get us the complete camshaft specs? That will tell a lot.
When I built my 400 off a stock rebuild long block, I used an Edlebrock Performer dual plane intake manifold, and HEI distributor that I had installed on the 351M the truck originally had. Those two parts were a big improvement on the 351M. Later, I added Hooker long tube headers to the 400, and a Comp Cams 255DEH, K32-206 camshaft. That was another big improvement. Whatever you do, break in that flat tappet camshaft properly and with high zinc break-in oil. You'll hear people argue that you don't need to. I can vouch that you do.
When I built my 400 off a stock rebuild long block, I used an Edlebrock Performer dual plane intake manifold, and HEI distributor that I had installed on the 351M the truck originally had. Those two parts were a big improvement on the 351M. Later, I added Hooker long tube headers to the 400, and a Comp Cams 255DEH, K32-206 camshaft. That was another big improvement. Whatever you do, break in that flat tappet camshaft properly and with high zinc break-in oil. You'll hear people argue that you don't need to. I can vouch that you do.
Tuned
Joined: May 2006
Posts: 304
Likes: 77
From: St Paul MN
400s are a stroked 351, they got a bad rap because the later model years had a low power cam for emissions.
I have headers and an early model (pre-emmisons) cam on my 400 with stock 2 barrel carb and stock spacer. Runs good, plenty of power for my use. People have good luck with a spacer and four barrel carb.
Doesn't take too much to have them hitting respectable numbers, but there aren't as many parts available.
Nothing from that era will match the new diesels for towing capacity, and they are a little heavy for racing. They do go thru mud as good as anythingfrom a factory out there.
This goes thru it pretty good
https://www.google.com/amp/s/www.mot...gine-build/amp
Lots of people suggest rebuilding your own, as you know what you've got then (which is what I did, with the help of a local mechanic it is doable)
I have headers and an early model (pre-emmisons) cam on my 400 with stock 2 barrel carb and stock spacer. Runs good, plenty of power for my use. People have good luck with a spacer and four barrel carb.
Doesn't take too much to have them hitting respectable numbers, but there aren't as many parts available.
Nothing from that era will match the new diesels for towing capacity, and they are a little heavy for racing. They do go thru mud as good as anythingfrom a factory out there.
This goes thru it pretty good
https://www.google.com/amp/s/www.mot...gine-build/amp
Lots of people suggest rebuilding your own, as you know what you've got then (which is what I did, with the help of a local mechanic it is doable)
More Turbo
Joined: Nov 2018
Posts: 563
Likes: 143
From: CA
What this guy said ^. I don’t plan on headers though, manifolds flow plenty.
Only complaint i’d have is pistons seem to be the big ticket item which you may have no say over on that reman, end up with the same ol pinging low compression open chamber.
Only complaint i’d have is pistons seem to be the big ticket item which you may have no say over on that reman, end up with the same ol pinging low compression open chamber.
Logistics Pro
Joined: Oct 2006
Posts: 4,029
Likes: 891
From: East Central Ia
400 get a bad rap because of the emission era, I'm not that fond of them myself. But will give credit due my Uncle had a 71 LTD with a 400 that would lay rubber for a block. JMO but lowered compression and lame camshaft really hurt them. Was the same for GM and Chrysler 455's 400's moaning quadreject carbs wide open and nothing happening. You may do well to call someone like Brent Lykins about a custom camshaft, not that much more money but may be worth it.
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Tuned
Joined: May 2006
Posts: 304
Likes: 77
From: St Paul MN
Neat, thanks for the info
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Cargo Master
Joined: Nov 2007
Posts: 2,238
Likes: 475
Tuned
Joined: Feb 2013
Posts: 418
Likes: 37
I'm purchasing a remanufactured 400 for my 1978 f150. I've heard that these engines are pretty sluggish with all the smog restrictions and such. But, I don't want to make the mods to go up to a 460. What would be some of the first things you would do to a 400 to gain some horsepower and torque. This is a project for my daughter and I. We aren't looking to get 500hp or anything, just a fun daily driver.
This is the engine I'm considering. Mabbco offers a handful of upgrades. What are your thoughts on those as well?
https://www.mabbcomotors.com/catalog...ited-warranty/
They also offer this one for considerably less, it requires a core (which I could do, and I'm in driving distance) but they don't offer near as many add-ons.
https://www.mabbcomotors.com/catalog...ock-1975-1982/
Thanks in advance.
1978 F-150
351M (currently, but dead)
Manual Transmission
4x4
This is the engine I'm considering. Mabbco offers a handful of upgrades. What are your thoughts on those as well?
https://www.mabbcomotors.com/catalog...ited-warranty/
They also offer this one for considerably less, it requires a core (which I could do, and I'm in driving distance) but they don't offer near as many add-ons.
https://www.mabbcomotors.com/catalog...ock-1975-1982/
Thanks in advance.
1978 F-150
351M (currently, but dead)
Manual Transmission
4x4
Sell it,,, Just joking. But at 1000$ i would not expect much, you will have the same ill designed pistions and still have to address your cylinder head choice. If you are going to sink some money into take it from me, just get a 460. I was in the "keep the 400 camp" until i started sinking money into mine.
If you are going to bolt on a few mod and have a fair running 400 to start, go 400, If you are going to search for better pistons and more choices for internals go BB.
I could not find a 460 local when i started my build and just checked CL last week and there are 5 or more within 10 miles of my home.
You can PM me if you want to ask a few 400 specific dos and don'ts.
good luck,
Chris
Super Moderator
Joined: Apr 2004
Posts: 34,495
Likes: 2,810
There are cams that will work "better" with low compression engines, but the 351M and the 400 share the same issues--low compression, weak cam, detonation prone heads.
All can be fixed but the prior posts note the difficulty and expense in doing so.
All can be fixed but the prior posts note the difficulty and expense in doing so.
Butt-Head
Joined: Apr 2004
Posts: 9,448
Likes: 2,934
From: Reed Point, MT
Building one for a guy right now.
TMeyer pistons, balanced, small roller cam (and lifter bore bushings), and intake.
I've put together a few stock 335s.....nothing "modified" though (see what I did there?) so I'm really excited to see how this pig does. Desktop Dyno comparisons make it look pretty appealing.
TMeyer pistons, balanced, small roller cam (and lifter bore bushings), and intake.
I've put together a few stock 335s.....nothing "modified" though (see what I did there?) so I'm really excited to see how this pig does. Desktop Dyno comparisons make it look pretty appealing.
Cargo Master
Joined: Nov 2007
Posts: 2,238
Likes: 475
I'd call that Mabco place and talk with someone. They say to call for performance modifications. I'd see about getting a 9.5 to 10:1 compression with mild cam long block, then do the bolt on stuff mentioned.
More Turbo
Joined: Mar 2019
Posts: 530
Likes: 89
I'd just do a 4bbl intake and 4bbl carb if you just want a driver. My 78 Bronco had a stock 351m with an Edelbrock performer and an Edelbrock carb on it when I bought it and it had plenty of low end pep for around town. It wasn't a high revving engine though and it felt and sounded like it'd explode if you revved it up to and above 4k rpm, but that probably had more to due with the overall condition of a 40ish year old engine. I rarely revved over 2500 rpm around town and cruising at 45 mph, which would be one of the higher limits in the city limits, was like 2000 rpm. That was with 31" tires, NP435 tranny, and 3.50 gears in the axle.