400 valve spring info needed

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Dec 22, 2013 | 03:02 PM

Justke

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400 valve spring info needed

I have a 1978 F-250 custom with a 400 in it. The number one valve springs have broken and I estimate the truck has 50k on the engine. Is it a common issue to break springs or is this a rare issue. If so what are the specs on the valve springs inside dia outside dia and height? Other thank headers an a carb the engine is stock as far as I know.

Dec 22, 2013 | 03:48 PM

BuzzLOL

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. As far as I know, 200,000+ miles is common for stock springs on stock cam... although a scratch on a spring can cause it to break quickly in that spot... maybe a key was left out of the retainer, allowing it to **** over... or a rocker arm broke...

. If going performance springs and cam, check the pricing on Howard's Cams springs at Howard's, Summit, Jegs, etc... Can prolly get even stock spec. springs at much lower price than at Ford dealer, etc...

Dec 22, 2013 | 04:16 PM

Justke

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So not going performance it's a truck I need to last and tow with right now. Want to do a complete build later to a new or good used block down the road. If it isn't a tough swap may go 460 because the parts are easier to find.

Do 351M parts fit the 400 for the most part or is there a lot of difference

Dec 22, 2013 | 04:18 PM

Justke

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Just bought the truck about 9 months go so no clue how old the engine is. Guessing mileage off of main bearing wear. I know it has been rebuilt at least once but no idea outside that.

Dec 22, 2013 | 06:26 PM

85e150

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Quote:

Originally Posted by Justke

351M = 400 as far as heads, valves etc. There are differences year to year, but a '78 351M is going to have the same heads as a '78 400 for example.

This says the same valve spring is used in all kinds of Ford motors:

NAPA AUTO PARTS

Dec 22, 2013 | 06:30 PM

Justke

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Thanks for the info. Makes parts hunting easier by far.

Dec 23, 2013 | 10:05 AM

BuzzLOL

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. Yes, 400 block is a taller version of the famous 351C block, and most parts and accessories interchange... I'd suggest reading several of the threads right here on the 400 engine before considering a heavier 460... '72 - '86 were not good years for the 400 or its later 351M variant... sluggish, weak power/torque, very poor MPG... however, a 400 can now be easily and inexpensively rebuilt to outperform even the first ones built in 1970-1971... to perform like the new engines in new Ford trucks... even like a Hemi...

. "Performance" doesn't have to mean a high RPM, weak low end torque, racing engine. It can also just mean a much better performing daily driver truck engine. Which is what most on here are wanting and building.