Beginners guide to increasing hp in 351 windsor

Hi everyone, I’ve just acquired a 1976 mercury cougar xr7 with what I believe is 351 windsor v8 under the the car. I’m not a mechanic but from what I understand these models have low horsepower. Would anyone out there be kind enough to give me some pointers on some things i could do to get a little more performance out of the car? I wouldn’t be doing any work myself but I’d be interested in getting engine parts/components to have installed by my mechanic. Any info for a greenhorn appreciated

Does the upper radiator hose go into the intake manifold or the engine block?

Most likely it is a 351M, which is a higher-deck block similar to a 351C. The Ford 400 uses the same block as 351M but crank and connecting rods are different, giving a longer stroke.

Post us some engine picture…

Sounds like a fun project. I might suggest a different answer to your question. Be sure your mechanic has some familiarity with the engine that you plan to have them supe up. Or at least they have good contacts that can steer you right.

You will get great advice here so don’t misunderstand my feedback. Great engine parts need a great install and tune as well. Depends a lot on your goals. Maybe just a different gear/LSD in the rear end will give you the extra pep you’re looking for?

Oh and yes, we love pictures.

For 1976 the 351W -2V was the base engine. A 351C - 4V was optional, followed by a 400C - 2V and a 460-4V. I do not believe a 351M was ever an option that model year.

Hey guys, thanks for the replies here’s a picture of the engine. I don’t believe it’s original but I’m told it’s a 351 windsor v8, heres a picture

Looks like a 351-W.

Here is a little bit of information found. In the end it simply depends on what your end goal is. What do you not want, what do you want and the compromises you’re willing to make. Just a precaution that modifying anything does have a tendency to open up a can of worms in both time and money. The alterations not only effect the engine but have an influence on everything else. I know this from experience. Before you spend any money it would be beneficial to fully research such a campaign and become aware of what’s involved. You do not want to end up with a basketcase and no means to an end. This happens more often than not.

The good news: All parts, stock or performance, are easier to find (in more variety) for the 351W you have.

Keep in mind the 351W you have may have already been rebuilt with an overbore. If you find when you do start digging into it that it really is a virgin 4.00 bore, that’s even better news…

Do you have a good mechanic already? One you can trust with you life the same as you would a doctor or lawyer? Otherwise ask around and see what others recommend. One that knows Fords. You wouldn’t go to an OBGYN if you needed your ear checked.
Heads make the horsepower. Cam, carb, intake dictate where the HP/TQ are. Lower rpms or higher rpms.
Figure out what you think it will cost and double it. You can’t just do an engine for 400HP. The whole drive train has to be able to handle it. 400 HP engine in front of a 45 year old C-4 and a 2.79 non-posi rearend, ain’t goin make it. Also suspension and brakes have to be up to handling it to.
Personally, a mild 460/C-6 might be a better option. You have the room.

Thanks for the input everyone.the car runs really nice so I’ll leave it alone for now, considering that tinkering with it may cause problems. Plus, when she gets going that front end loves to sway! Lol.

Many thanks to all


Not sure how long you owned the car but I suggest driving it for a few months and get to know the car. This way you will determine what it truly needs based on your experience with it. If you want to upgrade based on what you read about these cars and not your driving experience you might be doing a lot of unnecessary tinkering. Just my 2 cents. You got a very nice car.