300ci vs. 400ci
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Elder User
Joined: Oct 2002
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From: La Crosse, WI
300ci vs. 400ci
I have an oppurtunity to purchase a low mile 77' 400 out of an F-350. What are the pros and cons between my current 78' 300 and the 77 400? Hp, torque, mpg, that sort of thing? Disregarding the swapping issues. Thanks for your time.
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Joined: Jul 2001
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300ci vs. 400ci
I dunno about that mpg part. My old mans '80 F250 was lucky to get 8mpg on a good day with a tailwind. That only had a 351M, never mind another 49 cubes. (In all honesty, it did have over 250k miles on it)
That 400 has alot more rotating mass though less bearing surface. It also had some notoriety for being choked to death by emissions equipment. I do know you can make some decent HP figures and some REAL nice torque figures once you nix the emissions crap and add common boltons (just a straightup carb/intake/header will add tons to that old beast).
-=Whittey=-
That 400 has alot more rotating mass though less bearing surface. It also had some notoriety for being choked to death by emissions equipment. I do know you can make some decent HP figures and some REAL nice torque figures once you nix the emissions crap and add common boltons (just a straightup carb/intake/header will add tons to that old beast).
-=Whittey=-
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300ci vs. 400ci
My 300 gets 8-12 mpg in a 7600 lb truck.
Everybody I ever talk to that had 460's said it got 10-13 no matter what you do, up hill, down hill, towing, empty, it don't matter.
So, I'm willing to bet, mpg will not change significantly from 300 to 400.
Everybody I ever talk to that had 460's said it got 10-13 no matter what you do, up hill, down hill, towing, empty, it don't matter.
So, I'm willing to bet, mpg will not change significantly from 300 to 400.
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300ci vs. 400ci
>That 400 has alot more rotating mass though less bearing
>surface.
I think the 300 has more rotating mass. It has a longer, heavier crank and the same size flywheel and clutch. The 300 also has less pistons, so I'm guessing the 400 has more bearing surface, due to the extra rods and wrist pins.
>surface.
I think the 300 has more rotating mass. It has a longer, heavier crank and the same size flywheel and clutch. The 300 also has less pistons, so I'm guessing the 400 has more bearing surface, due to the extra rods and wrist pins.
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Elder User
Joined: Oct 2002
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From: La Crosse, WI
300ci vs. 400ci
Sounds to me like the 400's the way to go, especially if i throw on an intake and a new carb, possibly some headers. It has a 2 barrel on it right now and it runs terrible, (like the choke is stuck) the idle never kicks down, i'm going to check for vacum leaks, the choke and maybe the idle screw. After that I'll be probably rebuilding the carb if the motor doesn't start behaving. Any more advice??
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300ci vs. 400ci
>Sounds to me like the 400's the way to go, especially if i
>throw on an intake and a new carb, possibly some headers.
>It has a 2 barrel on it right now and it runs terrible,
>(like the choke is stuck) the idle never kicks down, i'm
>going to check for vacum leaks, the choke and maybe the idle
>screw. After that I'll be probably rebuilding the carb if
>the motor doesn't start behaving. Any more advice??
Yep, 400's have good amount of lowend grunt due to the stroke length. 4 inch bore, 4 inch stroke, nice square engine. The 300 has 4" bore and only a 3.89" stroke. Even the 460 doesn't have the 400 stroke, only 3.85". The 429 is 3.59" stroke and same bore as the 460.
I'd get a 4barrel on it for starters and do a nice tune up. Then get some headers.
>throw on an intake and a new carb, possibly some headers.
>It has a 2 barrel on it right now and it runs terrible,
>(like the choke is stuck) the idle never kicks down, i'm
>going to check for vacum leaks, the choke and maybe the idle
>screw. After that I'll be probably rebuilding the carb if
>the motor doesn't start behaving. Any more advice??
Yep, 400's have good amount of lowend grunt due to the stroke length. 4 inch bore, 4 inch stroke, nice square engine. The 300 has 4" bore and only a 3.89" stroke. Even the 460 doesn't have the 400 stroke, only 3.85". The 429 is 3.59" stroke and same bore as the 460.
I'd get a 4barrel on it for starters and do a nice tune up. Then get some headers.
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From: Metro Detroit (Redford)
300ci vs. 400ci
You may have a typo as I believe the 300's stroke is 3.98, not 3.89. Slight difference, but it is practically the same as the 400.
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INLINE SIX POWER!
'95 F150 XL300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."
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