250ci build up?

I have a 77’ Chevy truck that have been using to tow my boat. It has the 250ci inline 6 with 300,000 plus miles, with only minor valve work! It pulls great on the freeway, but lacks the power to pull through the mountains. I love the inline 6 and I would like to keep using it, instead of the usual 350ci that is in almost every Chevy truck. Anyone heard of a performance 250ci? Maybe supercharged? The motor is so reliable I would like to just rebuild it and build it up. It is so under tuned now, I believe is is capable of much more.

To be sure, you can get more horsepower out of a 250ci. We used to use them for dirt track racing in my mis-spent youth. However, I can’t think of much you could do that would make it a better boat towing engine than it is at its stock configuration.

A supercharger is not a bolt-on proposition. The whole combustion control system has to be configured around it. If you could not find a kit that was already designed for your engine (doubtful), it would be cost-prohibitive. Although it would give you more horses at high altitude, you might not like what it did to your mileage and driveability on a daily basis.

Clifford Performance specializes in performance parts for domestic straight-sixes: www.cliffordperformance.net

They sell an intake that lets you run a two or four barrel carb and a few sets of headers for the 250. This might make the truck a little zippier for driving around town, but it’s probably not going to increase the low end much. You could try to find a 292 which is essentially the same engine but with a little bit higher displacement-- the bigger engine along with the better carb and exhaust might make a meaningful difference.

There’s nothing wrong with the 350, though. It’s one of the most heavilly-produced engines in history so parts are plentiful and cheap and they are generally very dependable engines. If you’re putting any money into this truck, I’d say drop a 350 in it.

You may want to consider changing out rear end gears, you wouldn’t have to touch the engine and you can gain better towing performance. I’m not sure what your truck has in it now. But going to a 3.73 or even a 4.11 should help.

Thanks guys. It already has low high rear end gears, I’d actually like to make enough power to put in higher gears so I can go faster than 65mph. The freeways here are 75mph and I’m getting run over by the 80mph+ traffic. What about something like a vortec supercharger, that seems pretty universal. I can get a rebuild kit and a supercharger for way cheaper than a crate 350ci, unless I’m shopping the wrong places. I’ve also never seen a 350ci last 300,000 miles with so little work. It really says a lot for the little inline six being its lasted through 3 transmissions.

There is always someone who gets fascinated by the inline 6 in their truck.Really and honestly smart money goes for the small-block.I have worked with the 216,235,250,292 Ford 300 Chry.225 go with the small-block.Now the BMW inline 6’s thats another story.