Hi. I'm a forum lurker who rarely posts, as I don't know nearly as much as most of you. However, today I have a question.

I own a 351C that's been setting up for a few years. It was in my older sister's '73 Grand Torino. It wasn't the original, but was purchased sometime in the early 80's. It has about 50-60,000 miles on it.

It's completely stock but will need to be torn apart and checked out... It has a C6 Tranny on it, but 3rd gear wasn't working when it was taken out

I plan on putting it in a '76 SWB F100 and I want it to have enough power to pull your head back from the get go, but still get decent gas mileage.

Will leaving it stock be good enough? What about a new cam? Tranny? Headers? Carb?

I know what I want out of the engine, but to tell someone what stuff to put on it (if anything) I'm pretty much clueless. Also, this is the engine that I want to keep forever, as it has sentimental value... so to recommend any other engine would be pointless.

~HOSS

 

Not trying to be a wet blanket here but you need to be realistic in your expectations. IC engines of any type consume fuel and convert it into energy. The engine's power is directly related to it's ability to consume the maximum amount of fuel in the shortest amount of time.

Neck snapping acceleration doesn't come cheap especially when you pull up to the pump. Sure you could gear it low but that will run the engine at higher RPMs which consumes more fuel. If you build the engine with enough torque to overcome higher gears you still use more fuel to produce the power even at lower RPMs.

The 351C is not known for it's especially impressive low end grunt stock particularly in 4V trim. You didn't mention which version you had the 2V or 4V but either one can be built to impressive numbers with relatively little modification. There are several threads in this forum on good 351C builds.

Just remember you're putting a normally aspirated V8 with no computer controls and a 1:1 final drive ratio transmission, IOW no overdrive, into a heavy vehicle with the aerodynamic properties of a brick. You'll be lucky to achieve MPG in the low teens.

 

I just did a fairly mild build up of a 351M (converting it to a 400, which is a no-brainer if you want neck snapping power). Added a 255DEH cam, Edelbrock 1406 carb on top of a performer intake, flat top pistons, and that's about it - everything else is stock. I just did the break-in this past weekend - although I haven't driven it yet to find out real world MPG, I can tell you that I dumped 6 gallons into the tank, did my break-in at 2000-2500 rpm for 25 mins, and after this was done, I put it in reverse, and it immediately died. Thought it was the tranny going out on me, but it turns out I was out of gas! So, assuming 2300 RPM average, in top gear, that probably puts me at about 70 miles an hour. And assuming there was a gallon left in the tank, I used up 5 gallons for 29 miles. 6 mpg! Granted its the break-in, and things aren't perfectly tuned yet, and there is no smog equipment on the vehicle, but I've heard people getting, on average, between 8 and 12 mpg. Don't expect much more than that!

 

like cwheel said, my 400 is bone stock right now, right down to the 2v carb, and it gets 8mpg, it dont matter if it's empty or fully loaded pulling the trailer, it does 8mpg. but it will bang your head against the back of the cab when I kick it.

 

It's a 2V set-up.

I guess I wasn't clear in my expectations. I didn't expect to have power AND get 25-30 mpg. I'm fully aware of the drawbacks of what I want and expected somewhere between 9-14 mpg. Also something I didn't mention was that this will be my "weekend" truck... as in, I will drive it less than 3,000 miles a year. I have had trucks that get about 4 gallons to the mile and I didn't want to upgrade my 351C so much that all it is is power with no economy to it. 9-14 mpg is fine for what I intend it for.. Besides, when my sister had it in her '79 F100 it got about 12mpg (all stock).

I knew the 351C is unique from the other engines, and was wondering if anyone here had rebuilt one, what they changed, and what kind of power they were getting. I have searched through the forums using the search feature and haven't found anything specific...only, "I rebuilt mine putting in a new <INSERT here componant>and now I get 350 hp."

Basically, I'm looking for the information that cwheel posted, but for the 351C and not the 351M. Would the same mods work?

 

I'm sure they make all the same mods for a 351c....thats where I would start....cam, intake, carb.....rework the heads, flattop pistons, punch it about 30 over, it just depends on how much you want to spend on it...if that aint a problem, port and polish the heads.....

 

The 351M and 351C 2V use virtually the same heads as does the 400. The camshafts all interchange as well so any mods that apply to the 351M/400 apply to the 351C. The only thing "unique" about the 351C is the fact that it has high potential due to the excellent canted valve design and large valves. The smaller diameter of the main journals makes it a high revving motor capable of serious power in the upper RPM range particularly with the free breathing heads.

 

So basically, to upgrade the 351C a letter grade higher in power all I would have to do is to put this stuff on:

600 cfm carb on a new intake
255DEH cam

.... yea, as I said in the first post, i'm pretty ignorant about this kinda stuff trying to learn =)

 

I'm not 100% positive the 255DEH fits the 351C, but I'm pretty sure it does, and I'm sure Bill or someone else could confirm. Seriously, a decent cam, intake and carb does amazing things for this family of engines, especially if you "forget" to put the emissions equipment back on the vehicle. I can't wait to get mine tuned up and on a dyno. Too bad my C6 rebuild only lets my Bronco go in reverse right now!

 

Yes the cam and intake will help and if you don't get crazy with the cam fuel mpg shuld not suffer and may increase. Something else to consider is your compression ratio. If you up the compression ratio with the proper cam your engine will be more efficient at all rpms which translates in power and economy. Tell us what kind of budget your'e looking at. Throwing out all kinds of ideas is worthless if your budget doesn't allow it.

 

Budget? What's a budget?

Seriously, given that I'm not looking for any major upgrades I was thinking that I could spend $500-800 on it (parts only). However, over the course of the year, I'd be willing to spend $1,500+ on it...

Understand that I'm not looking to make a racing engine, just looking to upgrade just a little. If I could find something that would up the power AND economy, I'm all for that.