The Stovebolt Site Forums The Shop Area Engine Shop How much horse power is enough horse power???

I know this sounds like a rhetorical question. Kind of like how much money is too much money, but I am serious. I just purchased a 1958 Chevy Suburban that is in pretty nice shape. I bought it on line in the states while I'm currently living in Germany, so I'm a bit nervous. I did get a whole bunch of pictures so I am pretty comfortable with my purchase.

Anyway, it currently has a "later model" 250 that is supposed to run. I've always dreamed of getting an old GMC 302 straight six to hop up and put in it. Those are getting to be hard to find.

My intent is to resto-mod this into a nice daily driver. The number one goal is for it to perform as a truck. I don't want a flashy high horsepower show truck/trailer queen. I'm not going to run it down the drag strip. I do however want to be able to load it up with supplies/gear and be able to pull a trailer or camper and also be able to make descent speed on the highway.

All that being said, I'm curious about what everyone thinks about engine/horse power. Can I put some work (overbore, cam, intake, 4brl, headers etc.) into the 250 and make adequate power or do I need to go with a bigger motor. I want to stay with a straight 6. Call me sentimental. It currently has the original 3 on the tree and I don't know what the rear end has in it.

I'll cut this off here since this is starting to ramble. I'm new to the game and new to the web site so I'll take any helpful advice.

no such thing as to much hp

Don't go crazy, a 250 should do everything you could ask of a truck. The factory rear axle is good up to about 300 hp.

If you need more than a 250 can give, and still crave a 6, build a 292. Of course a small block will also bolt in.

The 302 is an awesome motor. A very nicely built street motor will cost more than $5000 and be limited to less than 250 hp with about 300 lbs torque. As I'm sure you are aware... 302 gmc motors don't fit well in chevy trucks because they are longer than the chevy motors.

I have a 59 gmc 1/2 ton longbed with V8. The original 336 v8 was rated for about 205 hp. The truck would do 60 mph all day long, and haul anything. I swapped to an OD transmission, and the truck would do 70 mph all day long and still haul anything. The 336 was tired, so I swapped it for a 59 pontiac 389 that was bored and stroked for 447 inches. The pontiac V8 was a bolt in replacement for the 336 gmc v8. The engine was too much for the factory axle, and ripped the housing apart within 30 miles of the swap.

If you really want to work your truck as a truck, lose the 3 speed. A 4 or 5 speed transmission can really help.

SwingDaddy: Thanks for the info. I didn't know about the difference in size on the 302. Sounds like the 292 would be the way to go if I need a bigger motor.

What do you recommend I do to get the most out of my 250. I don't want anything extreme, just want to make it reach its full potential.

You must be psychic about the trans. I was thinking the same thing. Do you know of any sources (make/model/year) for a 5 speed that would be a relatively easy swap?

You're going to hate driving it if you tow.
I've towed a small boat with a 225" L6, and I wished I had 2 more cylinders and 3 more gears.

Another plus for the 292 is to know that it's power is virtually the same as a 283 truck V8 and the torque (most important part for a truck) is identical. Also a hotrodded 292 can put out a ton of power for less $ than a 302 Jimmy.

Jimmy's are cool but a lot of them now on the market are military blocks and are less desirable and even more costly to rod.

Subs are very cool whatever you put in it. Good Luck.

I would go with the 292 like 53money said, I had a 69 Chevy 1/2 ton with a stock 292 and 4 speed with granny low and I out pulled a couple of 350.
By the way where are you in Germany? I was stationed in Mannheim Germany for 4 years

53Money;

Thanks for the info. I'll keep my eye out for a 292. In the mean time, is it worth the time and money putting some work in the 250 or should I leave it as is until I replace the motor?

Shoer;

I'm in Heidelberg. Been here 5 years.

Anyone have any ideas on a tranny swap (5 speed) to gain better performance and top end speed??

I have a 38 GMC that I am running a stock 250 and a T5 out of an S10 with a .73 overdrive and 3.42 rear end. I was looking more for the economy then hot rodding and the only load it will carry grocery from the store or something like that, I have other trucks for work and working.

My oldest son was born in the military hospital in Heidelberg in 1983

Larry..I think it depends on how you intend to use it. IF pulling a trailer is going to be done a lot and IF your in hilly country them go for the 292. But if all you intend to do is use it as a driver for weekends, etc. then there is certainly nothing wrong with a 250. Most of us really don't want to drive these trucks like they are brand new so we slow down and enjoy the ride.

Pick up a copy of the Chevrolet Inline Six Cylinder Power Manual by Leo Santucci (2001 CA Bill's Automotive Books) online probably from Amazon. It has a LOT of info on the last generation of Chevy inline engines. (194,215,230,250,292)
Just be aware that all of these are more expensive to rebuild/upgrade than those bent (V8) motors as this always surprises all first time guys.

Also you'll wan to check out Inliners.org for even more info and tech advice.

Put a 350 v-8 in it. This era of trucks were designed for v-8. They are plentiful & low priced. They run smooth & quite & will pull anything you put behind it. I'm getting ready to put one in my 56 with 3 2 barrel carbs on it.
I use a S-10 5 speed but if you are going to work it hard or dog it that trans. will not hold up.

Shoer: Hooah!

53Moneypit: I just want a truck that is strong enough to be used as a truck (carrying a descent load, occasional towing, etc.) It probably won't be a real workhorse. I'll probably stick with the 250 for a while and see how that works. I'll keep the T5 trans in mind also.

Wrenchbender: I like the idea of being unique. Everyone is dropping a SBC in their trucks (even the Ford guys are doing it). I'm kind of nostalgic for the old inline sixes.

I was at a truck show this weekend showing my 55 Chevy NAPCO and there was a guy next to me with a 55 Ford. He has a 390 in it and feels like it is just too much power. He said he breaks the rear tires loose way to easily. I figure he just needs to upgrade the rear suspension, but that was his 2cents.

My 55 is a bit sluggish with a 250 hp 350. I wish it had more torque and HP. But that is mainly because there is so much more to move with the 4 wheel drive.

Good luck.

keep your 250,visit TOM LANGTON stovebolt.web site he is the man when it comes to 6cyl chevy engines let tom know you are miltary.

Now, how much you need and want, is relative. I drove my '50 1 Ton for 3.5 years full time with a 216. I few times I hauled a 6000 pound trailer. It was slow doing that.

Now, the panel I drive has a 235 in it, and has 50% more power, the panel also weighs 1000# less. To me, the panel drives like a scaled cat. It's so fast!

However, the panel is no match for a "modern" truck, neither in cruising speed, nor acceleration!

For a quick boost in power swap in some 307 Chevrolet V8 pistons, they are a direct bolt and will raise the compression about 1 point. Be sure they are true flat top pistons, some are universal replacements and won't do much for the compression. There are a lot of cams available, but most will raise the power band to high for normal driving. Stick with a good factory replacement for the best torque. Header will help a little, but not really worth the hassle, just add a good free flowing exhaust using 2" 1/4" pipe and muffler. HEI ignition will improve the fuel milage and starting ability and should help with power if the points are questionable.

My engine is a stock 250 with a slightly bigger cam and 8.1 to 1 compression. Using drag strip numbers, a certified weight scale, and online calculators, my engine puts out 107 to 112 horse power at the wheels and about 125 or so at the flywheel. It pulls my antique engines and trailer (2200 lbs ) just fine.

Joe

All;

Thanks for all the good info and your personal insights.

Joe H: What about carb/intake? Do you run a 4-barrel? Is that worth the time/expense.

I think the bottom line is I'll wait till I get stateside in July and see how much giddy up it has before I make any decisions. Can't wait to give it a test drive!

I believe Mercruiser Marine offered some intakes with a Rochester 2-barrel for the 250. If you can find a small-bore Rochester 2G calibrated for a 265 V-8 it should be close to the right setup for a slightly over-cammed, increased-compression 250. Most people install WAAAYY too much carburetor when they do a street engine buildup and end up with a very peaky engine without much midrange torque.
Jerry

Hotrod Lincoln;

Ok. Count me among the ingnorant. I would have thought bigger was better. Very interesting....

Larry, I have run three carbs, two carbs and now back to one. All three setups run about the same, the more carbs you have, the more noise they make, not horse power! The one Mono-jet doesn't look so cool, but does run great. I could tune the three carb set up to run better wide open, but the fuel milage suffered. The two carb set up was easy to tune, but drank fuel as well, I used to big carbs, and am shopping for smaller ones.

I have a idea for a Quadrajet set up as soon as I get some metal for a intake.

Joe

Joe H: I obviously don't know much about carberation! From looking at hot rod/truck magazines all these years one simply assumes that a bigger carb or more carbs means more power. Evidently not.

Based on 53 Money's recommendation I ordered the Chevrolet Inline Six Cylinder Power Manual on line. It shipped today. Can't wait to get smart on hopping up an inline 6.

A engine will only pull in as much air and fuel as it needs. If the carb is to small for the required engine demand, then a bigger one will work better. Any modification to said engine, should require more fuel and air, thus producing more power, so yes a bigger carb will make more power, but not by itself.

Most of what you read is a sales pitch. Use some of the online calculators when figuring carburetor size and be realistic on the rpm range you are going to use the engine in, and you will find it won't be very big.

Here are some calculators for you to mess, with, http://www.wallaceracing.com/Calculators.htm


Joe

Joe:

Aha! That makes sense. I ran the calculator for a 250, at 83% VE for a mild street motor and a redline of 5500 RPM. Came out only about 400 cfm.

So changes to the motor will necessitate more fuel and air, hence a bigger carberator. A bigger carberator doesn't force more air and fuel into the engine to produce more power.

You are the man!

Pick the engine you want but in defense of the 350 I would say your sub was built for this engine,(265 etc.) and 350 parts are cheaper because of the popularity of them. That might be the reason so many folks (including Ford folks) run them.

2500 horsepower is enough horsepower

Big Chevy: I know. A lot of people say that. For now I'm still stuck on a 6 cylinder.

Brokenhead: You wild man!!

I saw some fella put a rolls royce merlin in a 55 chevy, look it up just google merlin in 55 chevy. That looks just about right to me.

Back in the day, the Allison Aircraft engine was a good choice.
Check it out:
Allison

that would be fine too