The Stovebolt Site Forums The Shop Area Engine Shop best torque?

I am open to all opinions here.....I have decided that a bit more engine is what I need to move things around, so I am going to get rid or the 250 currently in my 66 C20, and put in something that will allow me greater towing capacity. I can get a 292 at a local junkyard for 85 bucks and a complete rebuild kit with cam and pistons and all(stock though) for 350, but will that engine give me enough torque to drive up a mountain pass at 60 miles an hour with a trailer or a camper on the back? My goal here is best torque for towing. I'd like to keep it under 1000 bucks, and I would prefer to make as few mods as possible, I just don't know. I am open to lots of things, they just have to be reasonable. Horse power is on the back burner here and incidental. Thanks for your input. Josh

you will have more power because you gain 42 cu inches with the 292..look at the 350 hard..doc

If you are considering a 350, I would certainly look into a 454 also. It won't be much harder to install than a 350 and definitely will have more torque.

There are few V8s that will pull much of a camper up a mountain pass at 60 MPH without flogging them pretty hard. I was working hard in 2nd gear pulling a pop-up when I crossed the continental divide in Colorado a few years ago. It wasn't just me. Every vehicle on the road including diesels were working their butts off. I don't think a 6 will do the job.

THen my question is...will a big block bolt to an M420? I don't want to have to change the trans too, because then I will most likely have propshaft length issues.

Is a GMC V-6 worth looking into? One bigger than 302 if I can find it? Did they make much torque? Is there a website for them?

a big block will bolt to a bellhousing that fits the SM420.
and that same bellhousing will fit an L6 or a V8

Yes, a BBC will bolt to the SM420. The later bell housings that were made for the SM465 have the same bolt patter, but the center hole is bigger, so it does fit the SM420.

The V6 is a torque monster. Problem is that they don't like to be run wide open for extended periods. They are also expensive to repair, parts are getting hard to find. If you go this route, get the 351, it's a far better engine than the 305. It will pull the hills, but won't do it as fast as the BBC.

I remember dad driving up Wolf Creek Pass in out 64. 230 and 3 speed, with a topper and pulling a tear-drop trailer. Went up the hill at a solid 50 mph in second gear. If he had the 292 he probably could have done the same pull in 3rd gear.

The 292 will get down and grunt. Wish I could get my hands on one for under $100, they're not an easy find here, farmers used them on irrigation wells.

For a little more than your budget you can buy a remanufactured 350 from a dealer. It takes a lot more to get a rebuilt big block.

A friend of mine used to drive an early 60's Chevy 1-ton with a SM420 and a 396. If you are not playing hot rod the transmission will probably hold up fine.

I've seen several 454 powered pickups on craigslist over the last few months (in the Seattle area) for under $1000. One of them was listed as free.

Buying a used motor is always a gamble. But if you buy a complete used truck with the motor you want you'll likely be able to adapt many of the parts to support your swap. The basic frame design was the same 1963 through 1987, so much of what you need won't be hard to move.

I really like the power of my 454 powered pickup. But even with that motor a big load will slow me down going up hill. And I've come to think of 10 mpg as great mileage.

This might sound nuts, but turbocharge the 292. You can do it on the cheap if you do enough research and shop around. In all reality it's not hard to do. This way you keep the 6, keep the gas mileage of the 6, but when you NEED power, it'll be there. Do a few web searches on the subject...

If you're rebuilding the 292 anyway,it won't be that much more work to do some "turbo-prep" on it;8.0 to 1 pistons,forged if you can afford them,a good RV grind cam,a good ignition system,maybe an aftermarket intake manifold for better flow,and depending on how much boost you want to run,you might have to O-ring the cylinders. PAW will rent you the tool to cut your grooves,and they have the wire to use.
A friend of mine turbocharged the Dodge 413 in his race car hauler;he used twin Corvair turbo units,built a bonnet so they blew into an AFB carb,and he built an air box before the carb with 6 radiator caps on it. It worked as a waste gate,and he could set the boost by changing the caps. He ran 12 pound caps on it. That truck would RUN!It got full boost at about 1,500 rpm,and made enough power,with one car,all his tools and 4 spare race engines on the truck,pulling a fully loaded 2 car trailer,to run 75-80 mph all the way from Bakersfield,Ca. to Elko.I thought he was stretching the truth when he told me that until I saw him do burnouts with it,still loaded,out in front of his house. (of course,the street WAS still wet from the rain he was driving through all the way home.BTW-he said later he should have used a little bigger turbos on it so the boost would kick in at a little higher rpm.He could only run it to about 3500 rpm.)
Speed

Of course, it depends on how steep a mountain pass and how heavy your trailer (and how much wind resistance your trailer has, e.g. a travel trailer or enclosed car hauler), but in my experience it takes a STOUT V-8 to maintain 60 with say a 6000 lb trailer on a moderate interstate grade. A 454 or modern diesel can probably do it, but even a 350 won't be able to maintain 60 in most cases.

No way that is going to happen with anybody's 292.

Torque is only part of the equation - what you need is a certain amount of horsepower at the desired operating speed of the engine. You want to go up the hill quicker, it takes more horsepower. Period.

If you know the total vehicle weight and the gradiant of the highway, it is pretty easy to calculate the wheel horsepower needed to maintain any particular speed.

My trailer is rated at 6500 pounds and my truck weighs about 5500.

How do I calculate the horsepower needed to take 12,000 pounds up Monarch pass in Colorado headed to Utah at 70 mph?

I might choose that route in a couple weeks, though that leg of the trip I think the trailer will be only 1750 because it will actually be empty.

Don't forget about proper or desired gearing. As I've recently proven with my new O.D., being able to split gears on an sm420 or sm465 and staying in a good powerband will do more for you for towing than mildly hopping up your motor ever will. A warmed up motor would just be icing on the cake! The real problem will be trying to do any of the above for less than 1k. OldSub is right, with this much of a price restriction, a big block swap from a donor with the rest of the parts is your best option. And a gamble as well. And then, to be safe, you'll need to make sure your brakes and suspension are adequate which of course means more money.

Oldsub, the missing piece of information is - what is the grade (usually expressed in percent, which is feet of vertical rise per 100 horizontal feet of travel). I think normal interstate grades are 7% or less but I know of one in West Virginia that is 11%. But I have no idea what the worst-case grade might be on the route you spoke of.

Speaking as a Coloradan and with no insult intended, frankly it is completely foolish to drive our mountain passes at 70 MPH while pulling a trailer with a pickup or similar vehicle. We read about your demise almost daily in our papers.

Please don't do it. I'm on those roads too. Arrive alive!

That jogs my memory about the last time we were in Colorado. We went to Durango for a week. While in the mountains we drove pretty slow because of the grade, turns, etc. and were always passed by local (Colorado plates) drivers driving like they on the flat lands of Kansas. They'd take turns at speeds that I considered reckless. It wasn't a once-in-a-while thing either. It was all the time. Maybe the drivers in your area are better.

Locals do know the roads and that does make a difference but is no excuse for reckless driving.
And a LOT of those CO plates are on rental cars driven by people totally unfamiliar with mountain driving.

Come back and spend some money with us again soon.