Chevy 366 big block?

What does anyone know about the chevy 366 tall block motor. i know its used for school busses and heavy trucks… it has low horsepower and pretty decent torque at low rpms . i know it a low revving engine around 4000 rpms is it on gasoline . hp is 230 at 4000 rpms and torque is 345 at 2600 rpms… it has a long stroke and small bore … my friend at the bone yard gave me one with the 5 speed tranny out of a large truck. it has 60,000 miles I know its known as making a better for a boat anchor than being a desirable engine but they are designed for low rpms and decent torque and run 300,000 miles with little maintenance has a rev limiter. I’m considering using this as a wood gas engine for a pick up… keeping the 5 speed transmission . what are the thoughts for this?


From what I understand about fuels and internal combustion engines is that a slow burning fuel like wood gas needs a long stroke high compression low rpm engine of many cubic inches for maximum power. I think it was in a book by a guy named Cash that found larger c.i. engines lost less power on wood gas, as this book was written in the forties(if memory serves) all the engines were low compression. I do believe that Mr. Keith uses a belt driven blower to raise the compression ratio(correct me if I’m wrong please). Your 366 on wood gas is most likely as good as any and with the long stroke maybe even a little better than most.

Hmm. Check the valve head sizes on this engine. Very small versus a 409 and 454 Chev big blocks. Intake passages on this like a 345 IHC and even 351 W Ford versus 351C and M are smaller. These all like the first two generations of Dodge 318’s all had smallish intake ports and valves to promote higher velocity air speeds better able to carry through the carburator/throttle body supplied gasoline fuel droplets for better fuel efficiencies and lower emmisions. Later Dodge 318’s port fuel injected with the inject or pointed directly at the head of the intake valve really opened up the intake porting and many of these engines when port FI converted even opened up the valve sizing. Valve sizing ultimately becomes limited by the available cylinder bore diameter. So in the same displacement range a bigger bore then shoter stroke engine usually does better on power just because it can let in more air and fuel gases being larger ported and valved. Remember a roughly 1:1 +/- gases mixed ratio. Bulky woodfuel gas is now crowding out some of the air able to flow in when dense liquid droplet gasoline fueled. I’ve seen some maths now on air to woodfuel combustion chemical balances say even this is not that significant because simple molecule easily combusted woodgas gas components needs less air O2 to completely combust versus complex dense HC propane/methane and gasoline fuels. Modern higher possible compression ratios and cylinder/head combustion shaped turbulence understanding are important factors also.
TerryC not to contradict your reading but it is dated thinking. Bigger bore versus shorter stoke engine has a slower piston speed and therefore “seems” proving to be better for woodgas than a long stoke engine with a higher piston speed. Slower woodgas combustion flame front has a hard time keeping up, let alone as effectively pushing a higher speed piston through as many degrees of crank shaft degrees of push.

Bottom line John Wells is free is very good . . . maybe. Always best to use what you got like your 351W that is the best free. Engine/tranny swaps except into same manufactures chassis like a Chev/GMC set up for a big block always are difficult. Only for the serious gear heads. Not worth cross manufacturer swapping except for the challenge of it.
And never Race Mr Wayne for money or the bragging rights of winning. Fun only. And make him buy the suds anyhow.

Steve Unruh

lol no I’m not ripping out the fords drive train… I’m going to play with the 366 as a stationary motor for a while. i may put a generator on it just to apply load. then what to do with it if i like its performance…? was thinking of an el camino or a chevy pickup truck… i have a hard time turning down a free motor to play with. my next serious build of a truck will most likely be a chevy 454 with a 4 speed manual… i found a nice one but it was in southern california… and I’m in massachusetts… kind of a haul … but she was in good condition.

as far as the ford is concerned in thinking of stripping the motor down to the block and putting heads with bigger valves then just putting a basic intake and carb. and eliminating all the pollution junk which is still on and functioning. as it did when running on gasoline.

i have all these projects in my head … what to do what to do?

i put another 50 miles on the ford over the weekend :smiley: she’s running better and better… as long as my wood is dry.


Hello Terry C,

I once used superchargers as a starter blower . I realize now that they are not needed.

Mr. Keith,
I understand you have a book on wood gas. Where may this gem be acquired?

I am certain that I am dated. You are saying that a longer retention time in the cylinder for low energy slow burning fuels is not required? Clue me in. Where’s the paper? Inquiring minds want to know. I do not mean to be argumentative, I just need to study it. You are correct about piston speed being slower with a big bore short stroke engine ate the same rpm, This is why I suggested a low rpm long stroke engine. When I was littler we put 327 chevy pistons and ford 289 rods in a 302 ford for faster revving and to gain more bottom end and midrange power without sacrificing top end nor c.i. and installed it in a 73 Comet. If this doesn’t expose my dated thinking nothing will. What would be the ideal scratch built woodgas engine in your opinion? I would be interested in Mr. Keith’s input about a built for woodgas engine also, if he cares to weigh in. Has anyone contacted a good cam grinder about a doing a woodgas profile, we always picked the cam for the fuel, general engine specs, car weight, and altitude. I always went with a little more overlap than optimal on a daily driver 'cause I like it sounding like a top fueler at a an idle. Thanks for your input.

for some reason i seem to think the 366/454 were of a common ancestor age… much like the 305/350 chevs of days gone by.

so you could probably put 454 heads on a 366 engine… i’m pretty sure the 366 and 427 shared a forged crank…

just a thought is all… and don’t quote me on it.


Short answer is when we get time to write it. Follow the discussion here:

Hello Terry,

It is going to be a while on the book. To make sure we get it right it might take a year.

I am videoing and documenting the building of a gasifier on a 92 dodge Dakota. The fact that I am having to set up to try and video the entire process it its taking about three times as long to build this one.
Many are already building from the information that we have on the site already and I have about three hundred short clips in the pipe line now.
If there is something in the building of the truck and gasifier that I have to change it is easy to alter on the web but can’t if it is in print.


If I were building a motor for woodgas I would bring the compression up as high as it would run on gasoline.

In picking a vehicle it will depend on what you will be using it for, transportation or work.
I try to make sure they have plenty of power on gasoline so that a reduction of power when on wood gas will not affect the operation.
Plenty of room under the hood and under the truck, wide range of gearing. Muilti-port fuel injection.
But most important is I feel that the machine is 25% of the process and 75% is operator know how and experience.
There is a very high risk that anyone’s first gasifier might bend some push rods.

Hi Mr Wayne you sure are correct on your “Sucessful woodgasification is only 25% mechanical (process) versus 75% experience (operator).” wisdom.
Right their fellows IS the secret to woodgasification some of you’all I now seen for 4 years Internet searching for.
Shame is Mr. Wayne too many will still waste their time searching for some hidden answer instead of just taking to heart, “Only woodfuel burnin’ is learnin’. And only engine running on woodgas is really learnin’ well.”

Hello TerryC
Let me date myself too: 55 Ford I-6 -> 59 Ford T-bird 312 V-8 -> 56 Chev w/283 -> 55 Volvo B14 -> 57 Volvo B16 -> 62 Volvo B18 -> 74 Volvo B20 FI -> whole hat full of MG 1100’s and Austin America 1300 cc -> then a 1st generation VW Rabbit I tried everthing possible on in 79-80 and had Dyno baseline tested every step. Shhh! I was one of those real early terroist street racers.
Same time some of my Buddies when the 6=8 routes with American and Jaguar engines. Others, chased up the CID ladders starting with early Pontiac GTO “goat” V-8’s. Thats a thumbnail of personal modification experience.
Professional, paid for engine work, is another story with actual manufactures engine, carburation, FI and ignition classes.
As far as woodgasing fueling engine perrformance; the info is scattered in bit and peices all over the Net.
Only single modern book source I’ve found is Mr VesaM’s book.
2nd best is Any and All things put up on the Net about the gaseous fueled Austrian Jenbacher/GE stationary engines.
3dr source is hard to pull out gaseous engine fuel information studies from various US, China and India engine manufacturers and Universities.

The three combustible components of actual wood gas extremely easy to fully oxidize combust for power. Charcoal CO biased it has a slow flame front best speeded up with higher the compression ratios and conbustion chamber shaping. Raw woodfuel derived with an H2/CH4 energy bias it has a more rapid than gasoline flame front. Either way a shorter in cylinder pressure rise pulse. So NO - does not need a long in cylinder residence time. Does need a very earlier ignition lite off depending the actual compression ratio and combustion chamber shaping. All post WWII efforts say woodgas fueling is Best done with a big bore, large valve, slow piston speed engines. As you seem to know piston speed IS NOT engine RPM. Good.
Propane, methane, gasoline fuels much more dense and complex carbon and hydrogen chains are more difficult to completely oxidize and combust. Engines in use for these can span over the range of under square to over square bore to stoke designs. Depends on whether you want best power to weight ratio, or best fuel usage efficiency. Piston aircraft to chain saws - with auto engines in between.
Diesel and heavy fuel oils are the most molecular complex and energy dense of all the IC engine fuels and it is extremely difficult to rip all of those long, long complex H’s and C’s chains apart to get them competly combustion combined with O’s. Eg; Diesel engine soots. Best IC piston engines proven for these fuels to have the longest stroke, in cyclinder residence time as possible. Right up to the limits of mechanical possibilty in the Feet long stroked 178 Rpm, ocean going, supremely efficient ship engines.

Still realistically ain’t any of us going to be casting up and making IC piston engines. Use what you got around available to you. But no sence not picking the best possibilities for the fuel, eh?
I read once the military had made up some diesel chainsaws and light piston aircraft back in the 60’s when they were flush with money. Never made it past the trial phases - Test troops would not use them - too heavy - too slow - gets you killed.

I think Mr wayne is trying to get us all up to speed on woodgas and not ran over, killed, out on the highways.

Steve Unruh

I must admit that I think of stationary/industrial engines when I dribble on about “ideal” engines. I have always been a “mountain motor” fan leaving the small high revving engines to my fellows. An oversquare engine is the only way to go as far as I am concerned. I used to work in the dealerships before moving on to my own shops and diesels. In the diesel world is where I was turned on to the old budda’s, murphy’s, cats etc. 600-900 rpm motors(admittedly many were undersquare). Big bore, long stroke, low rpm, not ideal for car and truck motors. I once had a waukesha late model, high rpm, 6mza, flat head i-6, 400 ci, gas engine in a FWD lineman truck that had a 1800 prm red line. Van Papagan’s shift points were 12,500 in his small blocks! So much for Waukasha’s high rpm idea. :slight_smile: Most likely personal taste and the pocketbook will be the deciding factors as to the ideal engine. For anyone who is interested here is a site that has many formulas posted Automotive Formula's Thanks for the discussion.

Nice thread here… I had never even heard of a 366 until today… another thing to consider is how easy is the motor to get parts for ?

I’m interested in the cam question posed by Terry earlier in the thread. My project motor is a 460 Ford, with essentially stock C9 heads, and no porting. Stock valves as well. I am looking for a single plane intake that would lend its self to MPFI conversion. I would prefer to use an intake with runners that are not splashed with hot oil on the bottom. In my project car I have enough room for a tunnel ram in case that would work for MPFI, keep the intake charge cooler and help increase the VE of the motor. Plus one of those dual-quad style tunnel rams could have two different throttle bodies on it - one for gasoline and one for woodgas. Just looking for a good deal on one if you happen to know anyone that wants to trade, I have a CJ style Weiand Stealth that I no longer need. mostly ideas in this paragraph, but I am shopping…

Anyways… to the cam question. I have an aftermarket Competition Cams High Energy series 268H that has a noticeable idle, etc, etc… this cam was not picked with woodgas in mind, but I wanted to have a streetable ride that would dip into the mid to high 12’s on the occasional trip to the strip.

Based on my limited understanding of what makes a good woodgas motor ('cause I have no experience operating any IC motor on woodgas) it seems that we are after big low end torque, so a cam with good vacuum and off idle performance would be my best guess, something like a 4-wheeler cam or a RV towing cam. If the motor makes good torque, a 5 speed overdrive would be nice to have (I am stuck with an automatic for now)

Comp Cams will make a custom grind for you… it would be interesting to see a Woodgas cam bake off using a dyno, right ? I think Comp Cams is in Tenessee… within road trip distance for Mr Keith and Chris in GA, maybey worth the ride up from Fla for Woody he has a purpose built motor in a warehouse running a generator and may have selected a cam for it…

Hi John,

The 366 & 427 truck engines were built by GM specifically for the medium duty series trucks. The 427 truck engine is not to be confused with the 427 automobile engine. The 366 & 427 truck engines have a .400in taller deck than 396,427,454 auto engines. These tall deck engines have 4 ring pistons which are longer than auto pistons. The 427 has a steel crank. The only problem you will have with a tall deck is intake manifolds. Auto manifolds from standard deck engines need spacers to adapt to the tall deck. Special intakes may now be available. Also the distributor is .400 longer. In the early days before custom blocks were popular, the 427 TD block was commonly utilized for stroker engines. The weak link to the 366 is extremely small port, poor breathing heads & intake manifold. Also prone to dropping exhaust valves. Other than valves, these were very durable engines. Hope this helps out, it has been a long time since we used these engines.