400 stock redline?

[BreadPlus]

My truck didn't come with a tach, and I've got this awesome digital dash courtesy of intellitronix, and I've gotta set the max RPM. I know they don't spin super fast but a general number would be neat. Otherwise I'll hook it up and find out myself. I looked on other sites and it can be anywhere from 4000-5500.

[Gary Lewis]

You can see the specifications on our page at Documentation/Engines/351M & 400, and then the Specifications tab, then the 400 tab.  But, the HP peaks at 3200 RPM, and with a 2bbl carb, retarded cam, and low compression it isn't going to rev very high.  So you might set it at 4000 'cause I suspect you are gonna want to shift before then.

[BreadPlus]

Thanks a lot Gary. Now I gotta figure out what motor is in the truck. The vin goes 1F25GPGD1059! The decoder on this site makes it seem like a 351W, another decoder said it was a 302, yet this thing has the telltale marks of a 351m/400, and I'm entirely unsure what it is. I'm gonna pull a plug and stick a 5" long plastic rod in there with marks at 3.5 and 4".

[mat in tn]

there must be some way that you can tell. the 302/351 w engines look quite different from the 400 series. look up some pictures of each . the valve covers should be the simplest way to figure out the type at least.

[Gary Lewis]

BreadPlus wrote

The vin goes 1F25GPGD1059! The decoder on this site makes it seem like a 351W, another decoder said it was a 302, yet this thing has the telltale marks of a 351m/400, and I'm entirely unsure what it is.

There's something wrong with your VIN.  As shown on the page at Documentation/Specifications/Certification Label a 1980 should have an 11-digit VIN, and an '81 or later should have a 17-digit VIN.  But you show 12 digits - assuming the "!" isn't meant to be part of the VIN.  So something is wrong.

But if we drop the leading "1" it works, and a 1980 VIN isn't supposed to start with 1:

F25: F250 2wd pickup

 

G: 351 2bbl, which in 1980 would have been a 351M, and from the outside you can't tell it from a 400

P: Twin Cities manufacturing plant

GD1059: Order of assembly.  The 1059th truck off the line from Twin Cities, I think.

[old55pete]

Is there a coolant bypass hose from the water pump to the thermostat housing? If there is, it is a small block, 302 or a 351 W. That is a starting point

[BreadPlus]

PXL_20211030_163948135.jpg
I still don't know how to upload images but here's a straight shot from the front of the engine bay. No Windsor had the coil under the air cleaner like this does, as far as I know.

I was told it was a 400 (and it may be, 40 years and no written history), but judging the fact that it's all equally worn it's a 351m. I'll be setting the redline at 4500 and looking for a set of 2.73 or equivalent rear gears.

[Gary Lewis]

Here's your pic.  All I did was to copy the url and past it into the blank below "Or copy an image from the internet", making sure to wipe out the "http://" that is already there.  But it won't upload 'cause it is over 1MB in size, so I clicked the Big button in Resize.

And it looks like an M-Block to me.  The thermostat is in the block and it doesn't look like there's a bypass hose, although it is hard to tell on the latter.  Another check is 8 bolts on the valve covers and the fuel pump bolts are oriented vertically on the M-Block.

[Machspeed]

That's no 302/351W. From the valve covers, looks like a 351M or 400.  

[old55pete]

That is ether a C or an M, Not a windsor