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Old 08-10-2004, 10:48 PM   #1
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Do I need More Torque or More Horsepower?

I just towed my 30' Argosy home today after 11 years in storage. That's the good news. My Tow Hog is a 1977 Chevy 20 Van with a 350CID/auto and I think 4:1 rear axle. My rig weighs about 6,000# wet.

Ok, on the flats - no problemo - I can steam along at 65MPH all day. However, I don't live in the flatlands, I live in the Pacific North and hills are everywhere. On a typical 6% grade I can manage 42MPH in second gear with the pistons seemingly wanting to change holes. That seems unsafe to me, I can't get out of my own way.

What I don't know is what I need to get this rig up to something safe like 50MPH uphill. Is it torque I am missing? Or, just raw horsepower? I am willing to have work done on the motor, but I don't know where to begin. 4-bbl carb? New cam? Better ignition? I have to assume (probably incorrectly) that a 350CID should be capable of making say, 275HP if modified? I don't want to use premium gas, nor do I want a noise-maker, and of course being a van, there is probably less room under the hood?

Thanks for any advice at all!
mdeneen
Very happy to have my rig home at last!
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Old 08-11-2004, 12:06 AM   #2
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I am by no means any authority on this, but I do know that you can change your rear end to a lower gear and gain pulling capacity. I think that is the torgue power. However in doing this you will also reduce your gallons per mail ratio that you now have.
Don't have any idea what is the best match up. I live in the flat land, well we have a few hills, but not anything like where you are. It might be best to talk to the guys at your local auto service shop to see what they recommend.
Good Luck!
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Old 08-11-2004, 12:21 AM   #3
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Quote:
Originally Posted by mdeneen
I just towed my 30' Argosy home today after 11 years in storage. That's the good news. My Tow Hog is a 1977 Chevy 20 Van with a 350CID/auto and I think 4:1 rear axle. My rig weighs about 6,000# wet.

Ok, on the flats - no problemo - I can steam along at 65MPH all day. However, I don't live in the flatlands, I live in the Pacific North and hills are everywhere. On a typical 6% grade I can manage 42MPH in second gear with the pistons seemingly wanting to change holes. That seems unsafe to me, I can't get out of my own way.

What I don't know is what I need to get this rig up to something safe like 50MPH uphill. Is it torque I am missing? Or, just raw horsepower? I am willing to have work done on the motor, but I don't know where to begin. 4-bbl carb? New cam? Better ignition? I have to assume (probably incorrectly) that a 350CID should be capable of making say, 275HP if modified? I don't want to use premium gas, nor do I want a noise-maker, and of course being a van, there is probably less room under the hood?

Thanks for any advice at all!
mdeneen
Very happy to have my rig home at last!
You need torque. If your rear end is already a 4:10, then the carb 350 will not do, unless you do major mods. Those are likely to be quite extensive, and expensive.
Why not swap a fresh 454 in it, with matching trans? I know that some 3/4 and one ton Chevy vans came with this engine from the factory. Have a heavy duty cooling system installed, including trans cooler and engine oil cooler, and i bet your van will tow your trailer like a dream. I used to tow with a 1 ton Dodge van, and often miss the space it provided.
I now tow with a 97 Suburban, 5.7l Vortec, 255hp, and well over 300ftlbs of torque.
It holds 55 mph on most hills, as long as it's not over 5000 feet altitude. The rules change up there....
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Old 08-11-2004, 12:50 AM   #4
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Yea a 454 would give you the power you need.
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Old 08-11-2004, 06:52 AM   #5
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This idea of changing out the 350 for a 454 sounds intriging. Is this a regular kind of procedure? I mean, do engines of such bigger size generally fit into places where such smaller ones were? I doubt the 1977 van would warrant spending a fortune having someone carve out a bigger hole or do extensive frame modifications etc.

I'm hesitant to dump the van in favor of a new tow vehicle because I already have put lots of money into the van to convert it to a nice weekend camper, and the price of trading up significantly is pretty high. We like the idea of a van for towing because there is miles of room for our dogs and so on. I'll look into this engine swapping business. Any other suggestions welcome! Thanks--
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Old 08-11-2004, 07:09 AM   #6
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Originally Posted by mdeneen
This idea of changing out the 350 for a 454 sounds intriging. .....
Investigate your local yellow pages under Auto Engine Rebuilding.

There are national chains that exclusively exchange motors.

As long as the 454 was an option for your van, a changeout is possible.

Most all of the reputable engine exchange shops will give you a quote.

It's not likely to be cheap.
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Old 08-11-2004, 07:34 AM   #7
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A 454 will fit but the conversion is going to be very expensive, all accessory brackets, starter, water pump, manifolds, valve covers, oil pan, etc. will need to be replaced with those from a big block. Even the front springs should be replaced as a BB is so much heaver than a SB. The trans in there is doubtless a 350, it will never hold up behind a 454 when towing. You will spend more to have this done than the van is worth.

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Old 08-11-2004, 07:41 AM   #8
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.....You are going to spend way more to have this done than the van is worth.

John
Right. So, coming down off that idea, isn't there some "bolt on" hot rodding sort of things that could give me a bit more power? I will check today with the two "engine shops" I found in the yellow pages (small town here), I'm just loathe to walk in with no real ideas. (Hmmmm, here comes a sucker...)
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Old 08-11-2004, 07:57 AM   #9
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Make sure you actually have a 4.10 axle to start. How many miles on the engine, what is its condition? 1977 was loaded with pollution controls but they are easy to remove. What you need is torque, you can change the cam, manifold and carb, add headers to get this but engine work is never cheap especially when you are working on vans, they are very tight.

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Old 08-11-2004, 08:00 AM   #10
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Aftermarket fuel injection?

Would add to the HP, and be better at feeding the engine than the carb. That along with a cam could increase the HP/torque to the point where you are in your comfort zone. This of course assumes that the rest of the engine is good.
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Old 08-11-2004, 08:02 AM   #11
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Quote:
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Right. So, coming down off that idea, isn't there some "bolt on" hot rodding sort of things that could give me a bit more power? .......
The reality is, unless you have a truely exceptional van, it is difficult to justify any real expense for an add on (especially if your van is "high mileage", >100,000 miles). True, there are many vans with 150,000 to 250,000 miles on them, but the expense of keeping a high mileage vehicle becomes greater and greater with each passing year.

You will have to realisticaly evaluate your present van, get a real world estimate of what you would have to spend to get into a newer vehicle, (I think e-bay is great for mid to high mileage used vehicles - there is so much buying ad selling competition that it is easy to assess what a vehicle is really worth), and then make a decision to put the bucks into your '77 or pick up an '87 to '90. Keep in mind that once a vehicle goes off of the "Edmunds" or "Kelly's" list, there is usually no further significant depreciation.

Good luck in your decision, but keep in mind than you will be stressing the engine, transmission, and running gear on your almost 30 year old van when towing. It's tough to decide when to trade up when variables such as dependability and inconveniences of a major breakdown when towing are involved.
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Old 08-11-2004, 08:25 AM   #12
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77 was right in the middle of the worst of the gas crunch. What a 350 of the late 60's and a 350 of the 90's makes powerwise that poor motor is like a V6 to them.

If your dealing with the emmsisons Nazi's you got real problems. Everything you do will have to pass their scrutiny. California is the worst about it. I think you still need to smog back to 75. While you can swap to a 454 and belegal it will take a lot of effort. As I understand they want to see a newer 454 and you have to meet the emissions requirment of the year the motor is. Well your truck probaby doesn't have Cats but an ewer 454 may require you to add them.


I would start with the basics. A REALLY indepth tune up. Including checkign the timing chain for looseness, fully inspecting the distributor, back pressure check on the exhaust. complete check out of the carb. You may uncover some power but some indepth tune up stuff.

The motor is old and even low miles age does cause issues. On both my 70's GM trucks I have had problems with the distributors being gummed up and causing ignition advance problems. If your advanced timing was not where it was supose to be it would soak up power.

Jetting issues with the carb is also a big deal. What was the altitude where your having problems? There is a HUGE power loss on a motor jetted for sea level and then taking that same motor up to 5,000 feet your going to loose a LOT of power.

So don't give up yet on what you have. Take some time to investigate some of the overlooked small items that may bring that motor some cheap power.

Before you change out anything you need to do a little reseach on what it will take to be legal in the police state "The Rupublik of Kalifornia. The emmisions Nazi's in your state are the worst to deal with when doing any type of modifications. They will make you jump through hoops and they will verify C.A.R.B. numbers on replacement hot rod parts.
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Old 08-11-2004, 08:26 AM   #13
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If you have a two barrel carb, I would replace it with a four barrel Quadrajet. Have a mechanic scope the engine to make sure it is firing good on all eight cylinders. Anything more than that would probably not be cost effective. I just sold my 77 GMC for $200.
I think with a 350 and a 4.10 rear end, your problem is horsepower, not torque.
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Old 08-11-2004, 08:27 AM   #14
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The '77 van has 130,000 miles - it ain't no spring chicken. It seems tight, runs well, doesn't burn oil, etc. OTOH, I do understand the concept of sending money down a rat hole, and sure, if it's just not doable, I'll flog the thing and find something else. But, I am rather attached to the dumb thing, because of all the other work and $$$ into it previously.

I figured if I could give it a boost for say, $1,000 I'd be willing to do that. Getting into a newer tow, say something with 50,000mi, will sell for about $13,000 around here. i.e. 1995 Suburban or something in that range.
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