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1. I have my grandfather's 1960 Chevrolet C-60 that he used as a grain truck on his MN dairy farm. After he retired in 1980 he stored the beast in the barn where it sat for near 20 years. We had to tear the old barn down and the beast resides with me in Montana now (hauled it from MN). After some tuning, a rebuilt power booster and a few odds and ends, it runs well. I now use it for hauling topsoil or gravel on occasion. The 19500 GVW seems a little underpowered. After replacing the leaking valve cover gasket with silicone, I noticed several of the push rods were bent. In an attempt to replace the rods, I found out the engine is the original 261 ci. The engine stamp, header stamp, and carb all original (thanks to inliners.org for helping me verify numbers).
Like I said initially, it seems underpowered. Is there anything I can do to improve horsepower without major work on the block?
2. I also have Grandfather's 1942 Dodge 3/4...all original or NOS. It has the Original Block with only 60,000+ miles and after restoring it as best a 1st timer could, I run it around regularly. The flat head 6 doesn't leak a drop of oil and runs like it just came off the assembly line. But at 35-40 mph the engine sounds like it is ready to come through the hood! Did I mention the gear ratio in the rear end is the lowest made that year? I would love to run it down the highway at a nominal speed...any suggestions?
Last edited by 42Dodge; 09/23/16 12:35 AM.
R.A. Fasching
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Hi, wow, love those old trucks. FWIW I watched a friend working on getting a '35-'37 Chevy started. It still had some old gas in it, which varnished on the valve stems, made them sticky, and as a result bent some push rods. He took off the rocker arms, popped the springs, and spun the valves with a drill. Replaced the bent push rods and off he went. The truck ran really smoothly then.
Mark
'67 Camaro L6-250
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The 261 is like any other engine, more gas better exhaust. Bolting on a dual carb manifold is likely to help but keep in mind that the 261 was advertised to make under 150 horsepower in stock form. The 54 version made 123. So in order to increase horse power without major rebuilding means bolt on power enhancements. So you are stuck with intake with dual carbs, dual exhaust, maybe even Barker High Lift rockers (pretty rare to find these days). Otherwise you are left with optimizing your current set up. One thing is that a 261 used a different carb then the 235 but because they looked virtually identical, its not uncommon to have a 235 carb on the 261. You might want to sort that out as the proper carb will help. Also optimizing your timing, making sure the vacuum advance is working. Does your 261 have a governor on it limiting the rpms.
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Thanks for the insight. In, fact there was some old fuel in the tank when I first started it a year ago. I was provided some advice to "just run a couple tanks of premium through it". Hmmm ... no doubt the valves may have already been sticky and thus the bent rods. It's looking like I may have to remove the head and give a thorough cleaning before installing the new rods.
R.A. Fasching
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How much power would you guess can be gained by simply bolting on dual exhaust and carbs? I will check the carb to see what it might be. The 261 does have an antiquated governor on it. I noticed on the ID plate in the cab that there were three engine ratings for the C60; 235, 261, and a 283. Will check out the associated hp ratings chevy embossed on the plate.
R.A. Fasching
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It sounds like you are very lucky to have found a couple of old trucks that have not been messed with. The old Chevys did an astounding amount of work with 216s and 235s. The 261 was a total work horse. That said they did it with torque and gears. I'm sure you can get more out of it but it is what it is. Many old trucks that size had 5 speed trannys with 5th gear being overdrive and some had 2 speed axles. If yours doesn't have those it might be something to think about.
On the Dodge I'd change the rear end gears. maybe 3.55 or so. Depending on tire size that would get you around 60 mph at 3,000 rpm. It would still have plenty of power for regular 3/4 ton pickup work. Dodge also made some trucks with 5th gear OD transmissions. My dad was a MOPAR flathead six guy we had a lot of them through the mid 60s. We moved from Texas to California in a '52 Dodge 1/2 ton 3 on the tree pulling the biggest Yuall-Haul they had. A little slow up some of the mountain passes.
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
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As to the pushrods, the originals are not as good as the sealed power replacements. They are not that expensive so you might just want to replace all of the pushrods at one crack, readjust the valves and my guess is that the motor will continue to run well. If you do go to the trouble of pulling the head, you might as well just freshen it up while its off. If the valves are good, they just might need to be refaced. Then its bronze valve guide liners (don't try to replace the cast iron guides, you might break one or the head. Use the liners), have the top of the guide machined for new style teflon seals, fresh facing for the valve, fresh facing on the head and a good cleaning and assemble. Take a pass on hardened seats. You will never in your lifetime put enough miles on that truck to see any issues because of low lead. I just took a 235 motor out of my 57 that I beat on pretty good for nearly 30 years. None of those years did I have access to leaded gas. When I took it apart, the seats were just fine.
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The ID plate in the C-60 rates the 261 at 148 hp (at 4000 rpm). Am taking your advice...new push rods are on the way. If I remove the head will ensure to "freshen" it as stated.
Beater of the Pack ... am also going to to look to change the rear end gears to a better highway speed ratio...it currently has a 3 speed on floor and is so low geared I can climb trees with it. Ah, Work Duty (WD-15) trucks....
R.A. Fasching
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So you are stuck with intake with dual carbs, dual exhaust, maybe even Barker High Lift rockers (pretty rare to find these days). I have two sets of Barkers in hand: Inliners Post circa '04 will part with a set - but I am skeptical of this particular mod (though period correct) - and view them now as a coffee table item suitable for inspiration not necessarily for installation. First (as others have pointed out in the thread above) they change rocker geometry/ratio but at the same time cant the push rods off perpendicular which may go so far as to cause the rods to rub on the head. But even absent 'rubbing' the canting will likely interfere with the lifter and rod rotating during lift - this will result in adverse wear on the rod, lifter seat and cam lobe. When I first contemplated these adverse side effects I thought to use the early '37-'39 cup style lifers and the longer push rods to minimize this canting effect - which is consistent with the California Bill speed manual. But when it is all said and done these rockers give you just a modest increase in .050 duration and lift - and only on the intake valves. But with the stovebolt head design it is really the exhaust port that is holding the engine back. Dual pattern cam grinds that extend the exhaust duration are a better investment: Inliners Post circa '15 If you are going to the trouble to pull the head and replace the push rods - why not pull the timing gear cover too and invest in a cam regrind, and new lifters as well? regards, stock49
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Thanks for the insight. In, fact there was some old fuel in the tank when I first started it a year ago. I was provided some advice to "just run a couple tanks of premium through it". Hmmm ... no doubt the valves may have already been sticky and thus the bent rods. It's looking like I may have to remove the head and give a thorough cleaning before installing the new rods. My friend just put rope down the holes before popping off the springs and spinning the valves. I think he did it twice, first was on one or two cylinders where the push rods bent. Second time it was after another push rod bent on a different cylinder. The second time he went through and did every valve he hadn't done before. But you're off and running, so no trouble now. Today's fuels are high detergent and will clean it out good.
Mark
'67 Camaro L6-250
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Keep in mind the stovebolts were designed to run on leaded fuel. If your running it hard under load there is a chance that you might have exhaust valve seat issues over time.
As far as modifying it - its a cost trade off. There are alternatives.
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Can't solved today's problems using the same technology/thinking that created them
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I know there are a lot of opinions on the hardened seats vs non hardened seats. I have done heads both ways over the years but decided to stop installing hardened seats. One of the reasons is when I had a very competent machine shop machine a very pristine 848 passenger car head, the machine shop hit a casting flaw (thin casting) where the seat was. We only discovered it after the motor was back together and running. These 261 heads have larger exhaust chambers (some of the 261 heads are 86 cc other are 95 cc) so the casting may even be thinner at the exhaust chamber with the 261 heads. I have not seen exhaust seat damage except on heads that had loads and loads and loads of miles on them. Further, I have a head that has never had leaded gas, no hardened seats, and i will represent that I used this motor hard for over two decades (including many shifts at the 5800 rpm range). When I took it apart this past year there was no evidence of the exhaust seat having been pounded by the exhaust valve. So my call, as of the last few years (and of course everyone will make their own call on this) is to not take a chance making a good head into a pile of scrap by hitting water. And for the record, the new 261 that I just built for the 57 is a 59 848 head, 1 5/8 small block chevy exhaust valve, 50-52 chevy powerglide 1 15/16 intake valves, no hardened seats. As much as I love driving the car, i simply will not live long enough to put 100k miles or better on the motor and do not expect to see any kind of damage. Just my thoughts, for what they are worth, lol.
Last edited by mdonohue05; 09/26/16 01:03 PM.
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After many words of discussion with my head builder, we came to the same conclusion. My little 4 banger doesn't use much gas. It doesn't ping or spark knock, and the car is light so the engine doesn't labor.
"You gonna' drive that thing 50,000 miles in the next couple of years?" he asked.
The answer was, "No!" so he said he'd eat that head if I brought it back with the seats bad.
"Good enough for me," I replied.
Never use a minor caliber bullet on a major caliber adversary
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I know there are a lot of opinions on the hardened seats vs non hardened seats. I have done heads both ways over the years but decided to stop installing hardened seats. One of the reasons is when I had a very competent machine shop machine a very pristine 848 passenger car head, the machine shop hit a casting flaw (thin casting) where the seat was. We only discovered it after the motor was back together and running. These 261 heads have larger exhaust chambers (some of the 261 heads are 86 cc other are 95 cc) so the casting may even be thinner at the exhaust chamber with the 261 heads. I have not seen exhaust seat damage except on heads that had loads and loads and loads of miles on them. Further, I have a head that has never had leaded gas, no hardened seats, and i will represent that I used this motor hard for over two decades (including many shifts at the 5800 rpm range). When I took it apart this past year there was no evidence of the exhaust seat having been pounded by the exhaust valve. So my call, as of the last few years (and of course everyone will make their own call on this) is to not take a chance making a good head into a pile of scrap by hitting water. And for the record, the new 261 that I just built for the 57 is a 59 848 head, 1 5/8 small block chevy exhaust valve, 50-52 chevy powerglide 1 15/16 intake valves, no hardened seats. As much as I love driving the car, i simply will not live long enough to put 100k miles or better on the motor and do not expect to see any kind of damage. Just my thoughts, for what they are worth, lol. Dyno durability tests I have run support your findings - the threat of valve seat recession in older engines using unleaded gas is WAY overstated, especially in a car used mainly for pleasure cruising that does not rack up oodles of WOT miles. Not all early engines have the needed iron under the seats to reliably install seat inserts. A much more viable alternative if any seat recession is present is to just install a bigger diameter valve which allows you to move the seat area up on the chamber.
FORD 300 inline six - THE BEST KEPT SECRET IN DRAG RACING!
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Keep in mind this particular engine is in a dump truck when loaded the engine is working hard - its the heat in the exhaust valve head and seat that causes the damage.
Under light load in a car application different story.
Disagree if you like - I seen the results on non-induction hardened seat.
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Can't solved today's problems using the same technology/thinking that created them
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