The Stovebolt Site Forums The Parking Lot '60-'66 Trucks I6 vs. V6 engine

Hi, everybody!

I've been away for a while. Looking at pictures of trucks a lot but still can't buy one until my old house sells...

Anyhow, I just recently started looking at the 64-66 GMCs in comparison to the 64-66 Chevies I've been drooling over for the past year.

I thought the differences were cosmetic, but now I've learned that GMCs offered a V6.

I had always wanted the I6-292 because it was supposed to be much easier to work on than the V8. How does the V6 compare in that respect and also in power and reliability?

I'd mainly just be driving back and forth to work in my 1/2-ton max speed 65. No hauling or heavy-duty work.

What kind of engine might be right for me?

Thank you, guys!

Steve.

If you peruse the Jolly GMC site you’ll get a collectively strong opinion that the GMC V6 was the best engine ever built. If you buy a GMC for restoration I would highly recommend joining:

http://www.6066gmcguy.org/

From a durability standpoint I would agree. The crankshaft is far up in the engine block compared to just about anything else. Everything is over-engineered and built to run millions of miles. It is rugged and a torque monster. For pulling a big rig or a house or tree stumps it’s in a league of its own.

From a practical standpoint for a daily driver, I believe the V6 weighs over 850 pounds, and is sitting right on top of the steering linkage, which certainly doesn’t make steering any easier. They get very poor mileage, parts are rare, and finding a person willing or experienced to rebuild one can be a challenge. A rebuild will probably cost over $3,000 as well. There is a common swap adding a Holley two barrel carburetor for somewhat better mileage and ease of tuning, and electronic ignition can be added. There may be other upgrades I’m unaware of, but those are about the only performance enhancements I know of available for this engine series.

By comparison the I6 is much lighter, parts are readily available. High performance and cosmetic equipment is produced should you want it to really stand out. But these parts are not widely popular (compared to a V8) so the cost is higher than for a V8.

There is a reason the small block V8 is so popular and common. There are unlimited and reasonably inexpensive ways to build this engine for mileage or performance. It’s light and small and easy to work on. Parts are available nearly everywhere, including aftermarket components for just about any engine accessory, which really keeps the cost down the farther from stock you stray.

For a daily driver I would recommend either the V8 or inline 6, based mostly on personal preference. I am a fan of the I6, although I have not owned one in many decades. It turns out I enjoy the convenience, performance, and practicality of the V8 even more. I would only recommend the GMC V6 if you want to own/drive a restored GMC, or truly need the torque they can produce.

If you want to follow the pack, the straight six or a sbc, is the ticket, but if you want to stand out in the crowd, the 305 V6 will get a lot of attention, conversation and questions...

As a commuter, the I-6 or sbc, is the better choice, from an economy standpoint, but as Markeb stated above, your personal preference will be the determining factor, based on your wants, needs and desires.

There are fewer and fewer of the 305 V6-equipped GMC trucks still rolling, so you would be somewhat of a novelty at your local cruise or show!

Hi, guys.

Those are both great (and consistent!) answers. I appreciate that very much.

Sounds like I'm better off avoiding the V6. It's exciting but not in my best interest.

My priorities are efficiency, reliability, and ease of maintenance. Power and torque are less important.

So if I get my choice, I'm leaning toward a big I6, though from what you guys said, a small block V8 might not be out of the question either.

On the same topic, when I say "big I6" I'm thinking of the 292 because I'm guessing that the smaller I6 engines might be a little underpowered for a 1/2-ton truck, especially considering the speed and acceleration required for daily driving. Is that correct? For regular city/highway driving, is there a minimum size 6 I should be looking for? What have your experiences been?

Thank you again so much for your help, as always!

Steve.

My direct experience with the inline six stopped back in the mid 1960’s, so I’m no authority on the topic. But since I’ve liked the inline engines, I’ve tried to at least pay attention to what’s going on. In selecting a preferred displacement six, I’d consider the various sizes of the small block V8. Arguably the most popular small block V8 is the 350, and more recently the 383 stroker. But when I was young the 265, 283, and 327 were every bit as popular for family cars or hot rod engines. For a daily driver, I think any of the 230/250/292 family would provide enjoyable service. It just needs to be bolted to a transmission and rear axle that are well matched to the torque curve of the engine.

From what I remember (don’t’ take it as gospel) the 230 family shares many V8 components, like pistons, rods, and much of the valve train. They also have seven main bearings compared to only four in the 235 series engines. These are smooth running, long lasting engines that can produce great power - with enough money. The following Wikipedia article explains the lineage:

http://en.wikipedia.org/wiki/Chevrolet_Straight-6_engine

Hopefully another member with more experience with the 230/250/292 engines will provide some first hand input.

I have owned several 63 chevy trucks. Each one had a 230, and I have yet to have to rebuild one. Have replaced fuel pumps, gaskets...etc..but Ive yet to need to replace a head gasket or worse. I am building a big block, but the I6 will most definitely get better gas mileage. The big block "dream" is something ive worked on for 15+ years, and finally got old enough to afford to build one....but I plan to keep the 230 and crate it for later.

jon1963, what kind of driving do you do with your 230? Is it powerful enough to get you up to speed fairly quickly? I mean, are you keep up with traffic, or are you holding up traffic?

Thank you!
Steve.

jon1963, I just looked at your photobucket truck pictures. It sure looks nice! I love the side spare tire mount and the blue engine. Nice job.

The 230, and its little brother, the 194 are a bit underpowered for truck use. The 250 can make use of things like 307 V-8 pistons, which raise the compression somewhat, being flat-top instead of dish topped. There are also performance camshafts available for the 2nd. generation I-6 which will fit any size engine, IMHO. The 292 is a torque monster compard to the smaller engines because of its longer stroke, but it's no hero where gas mileage is concerned- - - -that torque comes at the cost of considerably more fuel consumed. For a daily driver that doesn't haul heavy loads, the 250 with some tweaks is a good choice. Thye're also a little more plentiful than the 292's.
Jerry

Thank you, Hotrod Lincoln. I was hoping to not modify the engine, but still, from what you said, the unmodified 250 is the best option. As with so many things, the in-between is a good choice. In this case, it might be my best choice of balancing power with efficiency, at least as far as an I-6 is concerned.

As for the V8 engines, I bet they continue the trend of increasingly more power/less efficient. Would you say the smallest V8 is more powerful and more fuel-hungry than the 292 I-6?

Thanks.
Steve.

I don't think you should discount the 250 in the GMC's. I have one in my 66 GMC and it doesn't have any problem maintain and reaching the interstate speeds we have here in Richmond Va.
Larryw

I do mostly city and country driving and I have no problem keeping up with traffic. Its definitely no dragster, but for an original engine with only 78,000 miles I have no complaints. No oil leaks, and still gets decent mileage. I have converted over to a pertronix ignition, which seems work just a little better than the points and I still retain the stock look of points. They have aftermarket manifolds 1x4 2x1 3x1 2x2, headers, cast iron fenton style headers, cams....plenty of goodies if you have the money. Seems that the inliners pay as much if not more than alot of the SBv8 guys. Currently its parked while I wait on a grill to come in. Have no headlights right now so cannot drive in NC without. Hopefully it comes in soon as I hate to see her parked.

Thanks, Larry. Is the GMC 250 just about the same as the Chevy inline-6 250? Are there any differences? The GMC V6 didn't come in a 250, did it?

It is encouraging that the 250 has no problem getting up to speed on the highways in Richmond. I've experienced Richmond driving several times, and a slow vehicle might get you run over.

Thanks.
Steve.

My six cylinder experiences stopped with the 235, but the reality for me was that the V8 had more power and got better mileage than the six by several mpg. This was basically because of driving technique. I was young, and with the six I drove with the pedal on the floor almost all the time. With the V8 I could achieve the same rate of acceleration with far less throttle. That and four barrel aftermarket carburetors were far easier to tune and lean out than the factory carbs on the inlines.

I wouldn,t avoid the v6 Mine wAS 10 FT TALL AND BULLET PROOF

The smallest V-6 is the 305.

I didn't read every word of every reply, so sorry if some of this is a repeat, but I've had just about every engine GM made in the '60's. They are all good. The 250 is a good all around engine. The 292 is a real good engine and actually my favorite in a 1-Ton. A Small Block V-8 is also another all around good engine. The V-6 is a power house, but likes to use fuel and today it can be hard to find parts for.

Bill

Thanks, Bill!

That's a great summary. I love to hear everyone's thoughts. You all know so much, and posts like this will pay off when I'm ready to buy a truck.

What I'm hearing so far is that a 230 is good, but a 250 will provide a bit more power and still be relatively efficient. The 292 and the V6 engines are probably too powerful for my needs.

The small-block V8 is still a mystery to me. So many people put the 350 in there, and I just don't need that, but a smaller V8 might be suitable. But if I want to work on it myself, an inline 6 is probably more appropriate.

So when I'm looking at trucks, I'll probably look for a 250, but I might consider a small V8. Either would probably be great for a daily driver.

That's my conclusion, but I'm still so ignorant on the subject. Any further advice you all have would be appreciated.

Thanks.
Steve.

So far I've had trucks equipped with the 230, 235, and 250 sixes, and also the 283 V8. I'm not so impressed with the 235, when compared to the later 230 or 250. I've got no complaints with the 283 either, but I must say that wrenching on the sixes is a whole lot easier with all that room around the engine. EVERYTHING is in plain sight and easy to reach (including the distributor). The simplicity is almost silly sometimes. Heck, you can fix just about anything with a screwdriver and a pair of pliers!

oem4m4, thank you for mentioning that! That's huge for me. I want an engine that I can work on, even with my limited (non-existent) mechanic's skills.

Since you've owned both, how would you compare the 230 and 250 for daily driving, efficiency, power, and maintenance? Is the 250 the clear winner? If you could only choose one...

Thanks.
Steve.

Is the 250 a clear winner over the 230? well, no. Not a big enough difference to be a deal breaker if you found a great truck that had a 230 in it anyway. I think either would probably be fine for your purposes. Much more important is finding an overall solid platform for a hobby/project truck that won't kill your fun factor while honing your skills at repair and maintenance. That said, 250's were in production for a long time and anything from parts to complete motors are everywhere. I frequently see V8 swap orphans complete from air cleaner to oil pan for a few hundred bucks.
Bottom line? I say look hard for the right truck. Try to find an unmolested original that just needs a little love and chances are whatever motor it has in it will be fine.

Great answer. Thank you! You're right. I need a truck that runs fairly well from the start. If I've got that, I'll probably be happy with whatever engine is in it. That being said, I'll be excited if I find a 250 and still happy if it's a 230 instead.

Thank you, oem4me (and everyone else).

I'll go along with oem4me. The difference betweem a 230/250 is so little that I'd take either. A good start with the body would be more important. Larry

Thank you, LarryW!

That makes life easier when it comes to picking a truck.

Have a great day.

Steve.

then what happens next is(with a 230-250) is doesn't go fast enough or it makes to much noise at 60mph. a lot of times one doesn't get good enough gas mileage, so the conclusion is , we need a higher gear ratio.
. figure out what or how you want to drive it otherwise you will be changing things and then saying this is what I should have gotten. these old trucks were not really built for freewayrons

padregsag, yeah, I know.

I love the idea of owning one of these old Chevy or GMC trucks, but in terms of modern safety, handling, braking, and driving in general, in stock condition, they will lack the feel I'm used to.

I don't understand the first thing about gear ratios. When I do get in a position to buy a truck, I hope to have all these bits and pieces figured out. I know I'll need to make modifications, but I want to make as few as possible, and they need to be the right changes so I don't have to redo it later on.

I know I'll be coming back to you guys again and again as I plan my dream truck.

Thanks.
Steve.

I’ll put a sharper point on what I believe OEM and LarryW are stating. If you’re new to the hobby with limited experience in vintage vehicle ownership or restoration, the absolute most important factor in buying any 40 or 50 year old car or truck is rust, or more specifically the lack of rust. The 60-66 series of trucks have common rust areas, which can be minor, or deal busting. Extensive rust can consume money well beyond the value of the completed repairs, and wipe out any planned budget before mechanical repairs or cosmetic improvements begin. This is especially true if you can’t do the repairs yourself. And beyond money, finding and repairing more and more rust can completely drain the spirit out of a project before you ever get to the fun part.

In short, buy a truck with the best bodywork you can find. Mechanical repairs are easy and inexpensive by comparison. If you can’t afford the best you can find, save up more money. It will provide greater satisfaction in the end, when you only have to deal with simple problems you can learn to accomplish yourself.

Markeb, thanks for driving that point home. It hadn't hit me until I read your post.

I'm not a mechanic or a body man, but of the two, I'll be better at dealing with mechanical issues, and it will be cheaper as well. So my best bet is to get a truck that runs ok and has a very good body. I'm in NC, and things get rusty around here. Maybe I should expand my search to the southwestern states. I can't imagine buying a truck I can't test drive first, but it might be my best bet so rust won't be an issue.

I feel like this I6 vs. V6 thread is going a totally different direction now, but it's all great info. Things like this will be a huge help to me. I really appreciate all the great things you all share on this forum. It's really terrific.

Steve.

I had a 292 in my '70 C-10 (it now lives in my 63 Chevy II) and I was able to keep up with CA traffic ok.

One more comment won't hurt I guess......
I like a I6. It's a good engine with good torque at low RPM. I wouldn't discount a truck with a V8 283 in it. I am a big fan of 283's. Everybody has a 350. I love the smaller SBC's. The original V8 Chevy's are very desirable and can get good mileage too. The trouble with mileage starts with everyone's need for 4 barrel carbs. IMHO.....A 283 with a 2 barrel works fine and has plenty of power for the Stovebolts and is a good engine for highway.

From the perspective of a guy who grew up around flathead Ford V-8's and 216 Chevvies, the 2nd.-generation Chevy sixes are more reliable, and produce more power than anything but some of the highly-modified 1st.-generation sixes. The 194 and 230 Chevy I-6's had chronic block-cracking problems along the valve lifter bores, which turned the block into a boat anchor. The 250's didn't seem to have as much of a problem with that, and the 292's are as rugged as a bank vault.

I've built several modified 250's that would give a V-8 a run for its money, and they still got pretty good gas mileage. For stump-pulling torque, pick a 292, but be prepared for the truck to swerve toward every gas station you pass. They really like their fuel! Add a 5-speed overdrive transmission behind a 250, or a 4L60 automatic with OD, and use a 3.73:1 rear end, and you'll have a good all-around daily driver that will keep up with traffic and still get some pretty decent fuel economy numbers.
Jerry

I had a 1967 Chev Suburban 4x4 with a 250 cu in I-6 and tree speed transmission. Got good gas mileage cruising and did well towing a Ferguson T0-30 and bush hog on a trailer.

Traded for a 72 3/4 ton 4x4 Suburban with 292 and four speed. Gas mileage was about 10 compared to 15 to 17 with previous Suburban. Pulled trailer a little better. Granny gear was handy pulling away from a stop with the tractor on the back.

Finally moved up to a 3/4 ton pickup with an automatic and a big V-8. Gas mileage was bad, but it drove much nicer.

I have a 78 F__D F-150 that I bought new has 300 six and has required no internal work in 33 years, still does not burn oil. So the inlines do hold up regardless of their heritage.

I have been very satisfied with the 250 inline six, and the 283 V-8. My first two 1966 trucks had 250's them. They were very dependable, and easy to maintain.

I currently drive a '66 with a 283 V-8. After putting on 65,000 miles, it has not needed any major repairs.

I just saw this topic and wanted to through my opinion is. However, I am biased as I have a V-6.

You can paruse my pics if you want to get an idea of what onwe will looked like all dressed up and ready to go.