bey modifying the carb like you said, larger jets, new power valve, what kind of hp gains should i expect, what about from adding dual exhaust>? oh yeah, 76 f100 351m

 

I don't know exactly what hp gain you should expect from those carb mods alone.

A lot depends on what shape your engine is in (good compression, well tuned, etc.), and how it's built (stock, performance mods, cam, etc.). If your engine is stock, it would be interesting to know where it came from, since the 351M didn't come in your truck originally.

I'd guess that if your 351M is a typical stock build, in good shape with decent compression, and well tuned, those carb mods (including the spacer) might give you an extra 5-10hp.

Getting any power improvement is not as simple as just sticking in different parts, though.

You have to be prepared to do some trial-and-error experimentation to find the right jets and the right power valve for your engine.

Same goes for the exhaust. The amount of improvement you'll see depends a lot on how bad the current system is.

If you've got a decent 3" single exhaust with a high-flow muffler, you shouldn't expect any hp gain from dual exhaust.

 

the exhaust on mine is tiny, i dunno what it is though. the engine is in great shape.are you certain that it isnt the original engine?

 

i went out and measured it, it was only 1 3/4 in OD

 

The 351M/400 engines were not available in trucks until the 1977 model year.

Are you certain your truck is a '76 model?

 

pretty sure, how can i be 100% sure?

 

Check the VIN number. Post it here and somebody can decode it for you.

There's also a web site with a Ford truck VIN decoder, but I don't remember the URL.

 

Click on Mil1ions user gallery in any of his posts, he has a link to a VIN decoder. I used to have a bunch of links in my gallery including that one but some users were giving me grief because I didn't have any pictures so I wiped out my gallery.