i have a 1979 f250 and i was informed that i need new belts and a new harmonic balancer, im still learning how to work on trucks, i can do that basics like oil change, spark plugs, changing tires, but i still dont know to much about working on trucks, could somebody help me figuring out what kind of harmonic balancer i need? would be much appreciated

 

The balancer is specific to the engine. To tell you what harmonic balancer you need you need to know which engine you have.
For example, assuming a 400 V8, Rock Auto www.rockauto.com shows three priced from $66 to $98. The expensive one though says it's for a Windsor engine. AFAIK there is no such thing as a 400 windsor so ignore that one.
BTW Welcome to FTE

 

i know its a 351 v8 bored out to a 400 v8 but i dont know who makes it...

 

You can't "bore" a 351 to 400. Both the 351M and the 400 are basically the same engine, both have a 4.00" bore. The only difference is the stroke is longer on the 400.
Do you know if this is the original engine? If it is, post the VIN number and I can decode it and tell you which engine it has. Another way, count the number of bolts in one valve cover. Let me know.

 

i just recently bought it, i believe it is the original engine but im not sure, ill go get the vin for you

 

i think itsEG403lO but i aint quite sure thats what it is, is it on the engine by the carb, i would just check the door but both doors are from a 78 f250 and arent from this truck

 

and question, how do i tell the difference between a 351 and a 400? sorry for the stupid questions, i really want to learn, trying to do all the work to the truck myself, grew up in a family of mechanics but im a geek and spent all my time taking computers appart instead of cars... now i live on my own and there 4 states away..wish i payed more attention as a kid

 

That's not your VIN. If the warranty plate on the door is the wrong one, check the frame. The VIN will be stamped in two places. In the engine compartment, the visible VIN is stamped on the top right (passenger side) frame rail. It can be anywhere between the radiator support and firewall, but most commonly found about inline with the alternator.
The hidden VIN is also on the top right frame rail, usually 8"-12" behind the front cab mount.

There's no way to visually tell a 351M from a 400. They're the same engine except the 400 has a longer stroke. Ford doesn't use any special numbers or anything on the blocks either. The only sure way to tell whether it's a 351M or a 400 is to measure the stroke.

 

As for the "stupid" question, there is no such thing.
A very wise man I knew used to say "the only stupid question is the one that wasn't asked." and that's very true.
None of this is automatic, we ALL had to learn at some point.

 

Also, your VIN should start with F25 (2WD) F26 (4WD) or an "X" in place of the "F" if it's a supercab.

 

its a f250 4wd custom/ok so i looked all over the frame rail and couldnt find the vin, but i know its a 400, a little yellow stamp said 400, any other places i could look?

 

do yo have the title for truck

 

i do, is it on the title

 

The VIN will be.
The fourth digit of the VIN is the engine code. If it's "H" it's a 351M, "S" is a 400.
Also, your VIN should start with F26H or S, depending.

 

A little late for this question, but why do they say you need a new harmonic balancer?