The Stovebolt Site Forums The Shop Area Engine Shop 235 versus 350

I have 235 I plan to rebuild and use in my truck. But my frind says the 235 will never beat a 350. Please give me some info to shut him up! Like the best horsepower & torque out of a 235. Any links would be nice. Thanks

I think you are on the right track with a 235. While a 350 sure has plenty of power, and weighs less than the 235, everyone has one. If you want unique, go 235. A dual carb setup and headers and your ride will be the coolest on the block. It bolts right in and looks stock for the 1953 and older crowd.

In terms of cost per HP, your buddy is correct. To make your 235 outperform a 350 you would have to spend many more dollars that you would building a small block chevrolet. Be happy with what you have.

Those who think sixes are the best should realize that Stovebolts from 1955 forward all came with an optional V8.

I just got done rebuilding a 235 for my '54. I had all the machining done at a machine shop and built it myself.I could have bought a reman V8 long block for cheaper than it cost me just for parts and maching. It's up to you.

A 350 could have twice the horsepower, but always less than 1/2 the cool points.

If you do decide to go with the 350 make sure one of the bolters gets your 235. Don't throw it away, they are getting harder to find.

I'm going with a 235. With Patrick's gearing in the back end it's going to go fast enough to be scary. With Fenton intake and headers I'm going for the cool points.

There is no substitute for cubic inches.

I've been driving a 454 daily for the last few months. I love the quick response and the way it pulls strongly any time I want power.

But it averages less than 10 mpg and I'm paying for my fun.

The choice between a 235 or 350 or something else needs to be about what you want your vehicle to be. A 350 will probably be cheaper to build and will make more power, but if your truck came with a 235 the cost of swapping might equal the savings on motor and rebuild costs.

Think about how you're going to use the truck. If you want to drag race skip the 350 or even the 454 and buy one of those new 572s. If you want a cool driver the 235 might be your best choice.

Another 'cool' choice for a '61 would be something like a Buick nailhead, though it isn't likely to be a cheap option.

Beat it at what? Decide what matters to you and choose your motor accordingly. Unless its going to be your friends truck his opinion doesn't matter.

You have the power to choose.

At our anual old shool quater mile races here in Germany some of the inline 6 outraced some small blocks this year for the first time.

Most of them are hoped up 261 and 235.

F..d (Dang! There goes the F-word) inline 6 gets verry popular in the moment and a guy with a totaly insane Ford 300 inline 6 engine always blows the most V-things away.

But it is true if you want the most HP for the $ you better have a V8. :rolleyes:

Small block Chevys are like belly buttons - everyone has one! Be different, keep the six!

There's no doubt that the 350 will outperform the 235 any day of the week, unless you've done serious work to the 235. But, it all depends on why you have the truck. As long as I have my 52, it will have a straight six, because I like it that way. On the other hand, I have a 69 with a 350 that makes near 400 hp.

Now, go build that 235 and put it in your truck. Then you can get a newer truck with a V8, so you can have the best of both worlds.

It also depends on what you want to do with the truck. Like it or not, some mods HAVE to be done just so the truck can stay up with today's traffic. With the inline six, in stock form at least, they are extremely slow. To build one up to outperform or at least perform as well as a V8, you're going to spend a lot of money, probably more than it would cost to drop in a V8.

I do agree that a hopped up stovebolt engine is a lot cooler than a V8. So if you want the cool points, you can't beat a beautiful inline 6. Especially if it performs halfway decent. I'd say if you're cruising it or showing it, you might want the straight six.

If you want practicality or actually plan on using your truck for work or towing, then you should consider the V8. I don't think gas mileage is an issue, they both get pretty bad gas mileage compared to each other. In this case, the superior torque and higher redline of a V8 would be preferable. And you can make a V8 just as beautiful in an old truck as you can a stovebolt.

I'm surprised more people don't look to power-adders such as turbochargers or centrifugal superchargers to improve the power of an I-6. You would EASILY be able to outpower a normal V8 with a blown I-6. I'd like to experiment with that myself, but I need warmer weather to do it.

I agree with HotRodDad about why more people don't look to power-adders for I-6's. My thinking is that its because there are so few performance parts available compared to the thousands of parts and hundreds of companies making them for the V8's. One of these days maybe some of us will venture far enough outside the lines to use Pontiac OHC 6's or maybe even BMW I6 engines for some more serious power. Even a simple low cost FI system for the Chevys would be help a lot. I know there are some but still too pricey and no one seems to know much about them. So for now I'll have to settle for the $3K I have invested in 170 HP. (which is too much for my stock brakes :rolleyes: )

There is a super charger kit for an inline. But I think it illustrates my argument for a V-8.

Once you add a compressor you'll have some significant expense for modifications plus you'll be running premium gas.

I've not seen a turbo setup for one of our six's, but I haven't been looking either and it would be the same story. Lots of money, premium gas, and still have trouble matching the power output of my stock big block.

It's not that everyone should run V-8's, but that if you really want performance you'll get more for you dollar with more cubic inches.

If you want cool the six can be a very good answer. If you start out by wanting to win drag races, other things being equal a big V-8 is the answer.

Another great option for cool has to be a big Buick V-8... I have one that may end up in one of my projects some day.

Before anyone jumps on me, I need to remind you all that I drive a GMC 270 on those days when I don't need to relive my youth with the big block.

Two words: Nitrous Oxide!

I'm building a 250 to about 225 horses and then adding nitrous for a 75 horse bump. Simple math: 300 horses are costing me about $2000. Since my truck is a 1970 I could have shopped wrecking yards for a low milage vintage 327 or 350 and installed it for under a grand. I'd of had more horse power right off and the potential to make even more horses. I would have also had one more small block in a sea of bolt on billet BS. I prefer to spend the money, do the work, and earn the cool points, and nothing says cool in quite the same voice as an I-6 with 3 carbs, split manifold, and nitrous!!

Boo

Yea Boo. My 292 puts out over 300 H.P. and by buying used stuff and watching my P's & Q's I have just over $1,000.00 in mine. No nitrous and it will do a number on many 350's, another secret to low e.t.'s is light weight, my 1932 Chev. pickup weighs 2460 lbs. and the 292 is very torquey, more than most 350's.

FI is easy...use junkyard GM parts. www.diy-efi.org/gmecm

My Clifford 194-292 4bbl manifold already has the bosses set up for injectors. TBI is even easier, you just need an adapter plate made to fit the manifold opening.

No amount of money will get more than 200 hp or 250 ft lbs of torque from a non supercharged 235 with a stock head,modified or not..Leo Sanducci,who runs a successful 292 powered drag car,and used to run a 261 powered drag car,told me his 1/4 mile time and car weight suggested about 275 HP with a heavily modified stock head on that 261.This is a limited use expensive drag race motor,spun nearly to 7000 rpm and with no power at all below 3000 rpm,totally unsuitable for street use.In addition,other than a few articles written 50 years ago,there is no reliable dyno testing figures on the 235-261 engines.
There's a lot of BS about the power from these old lumps.When I was building the 302 GMC for my 37 Chevy truck,guys talked about massive power from the 302's.In reality,for street use with a somewhat stock head,they make about 250 HP at 4500 rpm,but with good torque,maybe 320-350 ft lbs at 3000 rpm.The 302 head,with it's large ports and modern wedge shaped combustion chamber with unshrouded valves,make a 235 head look like something from the stone age.Like the guy says above,in my 2900 lbs 37,250 hp makes it go pretty good.
Buck for buck,nothing can outpower a 350 Chevy,and for the street,there is no replacement for displacement.

I have not seen a turbocharger kit anywhere for an I-6. I think you are on your own to make one work. Although the pistons are cast, they're very thick. So if you keep your boost to a low enough level, not more than 6 or 7 psi, the cast pistons will probably live a long time. As far as the rods and mains are concerned, they're more sensitive to high rpms than increased torque. So if you size the turbocharger so that it makes its power between 2000 and 4000 rpm, you won't really be dealing with too high of an rpm. The mild cam grind will keep you from going much higher than 3500 rpm anyway.

The T03 turbo that was commonly used in 80's Chrysler 2.2 engines would work very well. You could tap off of the remote oil filter lines to provide oil to the turbo, and gravity return back to the tank. The water lines would come from the lines to the heater core. And it would mount just below the exhaust manifold.

The most work would be making the adapter for the exhaust manifold and the hat for the top of the carb. It might possibly require moving the alternator to the other side, so some bracket fabrication would be needed. But all in all, I don't think it would be that hard.

What might be easier is mounting a centrifugal supercharger on the passenger side of the engine. Then all you're doing is adapting it to the carb. If I had a supercharger handy, I'd go that route. But I have spare turbochargers lying around from my Shelby Charger days.

A 6 psi system would probably only get the 235 up to around 200 hp, but the torque improvement might be up in the 300 lb-ft range. And aside from the premium pump gas requirement, the cost to superturbocharge an inline six is relatively low, as long as you keep the boost under control.
They already come with 8:1 compression, which is very compatible to forced induction.

I got about 230,000 miles off of a Dodge 2.2 liter turbo-4 and it only had cast pistons!

Tony is absolutely right "Buck for buck,nothing can outpower a 350 Chevy." However, it is also true that nothing, and I mean absolutely nothing, says boring as effectively as one more 350. It's up to each individual. As others have asked; what do you want to do with your truck? Someone mentioned 1961 as the model year. A very non boring V8 from that era would be a 409 -- ya - she's so fine - my 409!!!! If I had a ride from that era I would seriously consider it. That's actually one of the most difficult parts of building these old trucks. There are dozens of routes to take, and many VERY LOUD advocates for taking each route. It's easy to get the paralysis of analysis. Figure out what YOU WANT and go for it.

Boo

PS
My off to didspose of that posi for you is still good!

Well I think I am going to go with 2 webers on a offy intake run an hei off of a v6 and a high torque producing cam and headers. Should I do any porting and polishing to the stock head? This motor is going into my 1961 1-ton I plan transform into a 4-wheel drive for fun & street use only. Maybe pull another project to a show.

Any body can build a 350 it takes skill to build something diferent!

Definately do the head work first. That will pay off more than anything else you do and then give it some exhaust work. Last comes the need for a carb and cam setup.

Hey Chevyman - where did you get that 300+ HP figure from?

I'll agree with that.

Given your intended usage you might want to think about Boo's 409 suggestion. That would be different, cool, and more effective when you use this truck to tow something.

I guess my V-8 bias might be showing...

I would go for a 409 if some would trade for my 235 but I don't think thats going to happen. I have a ponitac 455 super duty if I really want alot of power. but that's just not cool.

if you wanna go fast and impress your friends with smoky burn outs go with the 350(like everybody and his sister)if you want a good reliable tough as nails motor that will haul your old truck as fast as youll wanna ride it go with the 235

Oh,it takes the same technique to make a fast 350 as a fast 6 cylinder,proper parts and careful assembly.
A big inch modified 6 is a fine engine and even a hopped up 235 is ok,only 160 hp maybe,but if you do the right stuff,have a strong torque band,it'll feel more powerful that it is.
Slowgo61,sounds like your project will be a load for any 235 to haul in todays traffic.A 292 would be an easy swap and provide far more pulling power and probably better fuel mileage.
If your out to impress the natives,hell, most of them don't know what the're lookin at.They eyeball the GMC 302 in my 37 with headers and a Holley 4bbl stickin off the left side.Then they ask if that's the original "flathead 6"

I did not realize we were talking about a 1 ton. I thought, or rather assumed, we were talking about a typical half ton. The fact that it is a one-ton opens up a whole new can of worms. I am a serious inliner type guy, but I would not recomend a 235 for a 1 ton truck that was available with an optional V8. I'd look into what V8s were available in that truck in 1961, and try to stay period correct. Remember GM introduced the 327 in 1962, and believe it or not there are more 348's and 409's sitting around in dark basements and garage corners than one would think, and either would be pretty cool. You can bump a 283 to 250 hp pretty easy and that was almost certainly an avaible option. Steve's nail head suggestion would also be period correct and way cool. Of Course, if you insist on keeping the 235, that's not a bad thing at all, but you are going to spend some serious bank on getting the kind of HP I think you are going to want. It's possible to bore and stroke a 235 so it comes up 260 inches, and then go from there with head work, cam, dual carbs, et, but remember, we spell custom rotating assmbling like this: $$$$$$$$$.

Are you beginning to understand what I said about dozens of paths to travel?
Boo

Don't be so fast to reject the Pontiac 455! Get some early valve covers and put GMC decals on them.

Some later 50's GMC's had Pontiac V-8s, and your 455 could be dressed to look like one of those. That would be cool and plenty powerful.

I'm not even going to get into this debate. It usual ends up too heated for rational discussion, but I think everyone knows how I feel about the V-8 versus I-6.
Scott

If you get to the point where you turbocharge your six, it would probably be a good idea to invest in port FI and some decent electronics. You can do a good job with junkyard parts to keep costs down, but there is a steep learning curve if you've worked only with carbs up to this point. If you go that route, write me off list. I tuned & raced turbo EFI sixes for years and never broke one. Converting an I6 to port injection with boost would be pretty straight forward using GM parts. GMCpanel's point about the Cklifford manifold having PFI bosses is most interesting. A boosted six can match the torque of an average street big block, but you need to keep the detonation and fuel in check if you intend to do it for years. That's why I'd strongly suggest port EFI. GM had mixture correction and some pretty aggressive knock retard festures in most ECMs from the late 80's onward. As suggested, by others in this thread, it all boils down to your personal version of what's cool. The folks on this list are definitely cool. - MikeV

hear hear on the Poncho 455! The torque of those engines is phenomenal. What a magnificent truck engine that would make. I've even seen one guy modify a 389 tri-power intake to his 455. If you do that, the 455 would be anything but a bellybutton, cookie cutter V8, and you'd need a supercharger on a 350 to make as much torque.
On my Firebird's 455 (465 actually) I pull down 14 mpg, which is the same as I get on my 235 in the truck.

Mike Vee, I'm not opposed to EFI for my truck's 235, I just always thought it would be prohibitively expensive. You mention junk yard parts to assemble one. Like what? I know they did a lot of EFI on the Jeep inline 6's. The firing order might not be the same, but if it's batch fire (which is typical for Chrysler), then it might still work.

I was referring more to the EFI systems that came on early 90's 4.3 V6s. Specifically the port injected turbo trucks. You could go with throttle-body-injection I suppose, if staying naturally aspirated. The natrually aspirated 4.3 trucks were very common and the yards are full of them. The best ECM for boosted port-inj apps would be the 122749, which came in 87-90 Turbo 4cyl sunbirds/grand-ams, 91-92 Turbo six GMC trucks, and naturally aspirated Quad4 cars in 1988-ish. It is definitely not a one week project, and there is a learning curve involved. You'd need engine sensors from the early 90s V6 (temp, O2, Throttle Pos, knock, MAP) and an HEI disributor that fits your particular engine. You have to lock the advance weights and change the module in a typical HEI to allow computer control of the spark curve. The stock GMC truck program can adjust fuel & spark as needed up to approx 15 PSI of boost. It's just my opinion, but 8 psi on pump regular is very doable. That's an extra 100 lb/ft of torque @2800 RPM. Used ebay injectors from a late model 5.7L Camaro or Vette would be about right for fueling and you'd have two extra. As for the turbo, I'd use no smaller than the Mopar T3 Garret mentioned above, and no larger than 91-92GMC Syclone unit(MitsuTDO6/17c). Something in-between like a Thunderbird Turbo coupe T3/60 turbo would be good for a low RPM 235 truck engine. The problem with boost, is that it gives you so much power out of the box, you start wondering how much more you can have if you turn it up <grin>. That is usually limited by detonation, which has a lot to do with the quench and compression properies of the subject engine. Many Jeep guys adapt GM systems to their sixes. Because most yankee sixes aren't hi-revvers, it's the torque numbers that are most dramatically impacted by turbocharging. The GM MAP based systems gnerally do not like a lot of cam timing. They need a good idle vaccuum signal. The up-side of EFI is it is "emmisions lean" (good milage) and has good knock-retard capability, which adds to engine life for sure.
MV

The early Clifford 194-292 manifolds didn't have the bosses. The later one I have has them, angled so that the injectors will point right at the valves. As long as you have one injector in each bank wired to a separate driver (most port FI systems have two injector drivers - they fire 180 degrees apart), there shouldn't be any trouble with the siamesed intake ports.

If it's a Chevy keep it a Chevy.Between a 235 &350 engine there is No comparison.The 350 will kick butt.Today you have too keep up with traffic or stay on the back roads or the porch with the dogs :p :p :p

That might present a problem, as the 1227749 is a single channel unit. No pairing, just all six pulsed at once. MV

What's the firing order of the 235? If the pulses in any given port pairing are 180 crank degrees apart, it might still be doable. MV

153624

I meant 360 crank degrees above - sorry. The devil is always in the details. That firing order would not be a good candidate for single channel batch fire port EFI in an engine with siamesed paired intake ports. The valve events in any given "shared" intake port are unevenly spaced, causing potentially uneven fuel distribution in a situation where the injectors are pulsed every 360 degrees of crank rotation. Looking at the front port for example, intake #2 opens 640 crank degrees after intake #1 opens. If the events in that port were evenly spaced they would be 360 crank degrees apart. The intake valve with the longest "dead port" time before opening would potentially get the most fuel because the injectors are firing every 360 crank dgrees. That points to needing a throttle body injection system instead. TBI systems are okay for low boost situations, given a boost referencing fuel pressure regulator. Hmmm, that plain vanilla V8 sounds pretty simple now <smile>. MV

If you have an aluminum manifold that doesn't have injector bosses, then create them. You have to have the desired pieces of aluminum heliarced where you want the bosses, then drill and tap. It's not hard to modify.