HOT 261 L6 Chevy? 250 hp possible?

Hey thanks...whats the hp rating stock?

 

hahahahaha!!!!

 

Here it is "offending" quaint little downtown Wayland Missouri...

http://www.youtube.com/watch?v=e0H5S31RuWM



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Memory serves that the motor mounts were staggered in order to provide clearance for the additional stroke of the 292 internally. Are there versions of the 292 with motor mounts straight across from each other, or are you referring to the 194-230-250 series?

 

"other versions" would be 194 215 230 250.

 

the 261 is an old design motor. basically related to 1933 or so chevy stovebolts. Not to belittle them the 261 is a truck engine and plenty tuff. And i,ve seen them really buzz by V8 small blocks. The 194/292 engine is a really strong built more modern motor. Ford 300", straight '6,s also as are jeep/amc 6,s. these inline engines respond well to performance improvements. they were built for low rpm torq. They are fun to drive and are reliable plus they can move out with a few tweeks to the motor. I have a 261 in my 39 chevy.

 

I have a 261 that was a re-man prolly 30 years ago and pulled from a 2ton 61 chev...

Assuming pretty much everything is avail. for these engines, what are some good combos? Been thinking about building a dual carb log style intake and split exhaust to start. I'd like a diff cam and springs around the same time . How bad does the balance on these engines tend to be?

I also have been planning to use a t-5 behind it and have a couple bellhousings but no tranny... Can anyone tell me which bellhousing is the right one to get to use?

Figger with some 3.50ish gears my '51 Chev should scoot pretty good...

 

right on.

1. twin carbs, and a split is a real good place to start.
2. Stock bottom end is OK for starters. Wait until it needs a rebuild, then balance it then
3. post 54 bellhousing, or send the input shaft cover/ thrust race to Buffalo Enterprises, and he will make the bellhousing adapter for your stock bellhousing
4. At least 3.5's but probably 3.7+ a better deal. Also depends on rear tire size too. Try to keep the revs around 2000 rpm at cruising speed.

 

I think 250 at the crank would be a buit much out of a 261. If you stroked it, maybe, check Inliners.org and the Webrodder 'stovebolt stroker' series.

The nicest thing about the 292 (IMHO) is the ability to bolt more 'modern' tranmissions up without adapter plates (the 292 and family have the SBC style belhousing). Speed parts are available either way. You can stroke and bore the 292 as well if you want even more power (torque, lotsa torque).

 

Hold on YOU CAN STROKE A 292!!!! To what ci and how!!!!!!!!!!!!

 

This is the car that turns high 15s/low 16s? You may think you got on over on a vette, but I'm guessing it was out of generosity on his part. My stock (other than exhaust) 350 4 door caprice will outrun ya by over 3/4 of a second, shifting at 4700 in drive, and gets the same mileage. I've got a box of timeslips and tens of thousands of road trip miles to back up that statement.

Back to the original question, analyze what the six owners are saying real closely before spending hard earned cash trying to make a performance car with an old six. There are many grand claims about what the sixes have done, but when it comes down to it, anything less than a full race effort gets beat by the OHV V8 guys. The bigger ones like the 292 and 302 take up a lot of that slack, but there is no replacement for displacement

The six would be a great nostalgia motor if your car was always getting beat back in the day. Looking at that many fading tail lights will certainly rekindle youth

 

Since the 292 shares the large journal rod size with the SBC, its conceivable to offset stroke the crank journal with the same possible combo of sizes you could as a SBC, provided custom rods and pistons wont break your budget. CID of 310 and beyond are obtainable with only modest boring and stroking sizes, more extreme cubic inches are there if you want go to 4" bore and even strokes beyond 4.25".....speed costs money, how fast do you want to go! The last 292 I did, went 8.04 @ Indy at the US Nationals in the 1/4 mile, at over 165 MPH. It was stock stroke, naturally aspirated, so the potential is there with these engines if you want to go inline.

 

That's respectable right there. And damn fast. You deserve props.

If you don't mind me asking, how much would that motor cost the average guy that's building a car in his garage without machine tools?

 

Im not wanting to go the speed of light.I would be completely happy with high 14's in the 1/4. So is the that reasonable out of a 292? Anyone done it on here?
Matt

 

Hi Shifty, that engine was a full boogie top dog NHRA Comp Eliminator motor,and while the OEM block and head and crank were still used, the extent of mods done to all of those pieces to achieve the HP required to run those #'s, is to say the least, extreme, even by todays standards. The main expense is going to be in the cylinder head, and the time involved in porting and reshaping and recontouring the ports. To get more of a visual you can check out : www.selfracing.com to see more of what actually is done to these heads to extract awesome flow out of them. Today, many people are taking the Frankenstein approach and cutting and welding two SBC heads together to get a good flowing head. But all the components in our engine had OEM block, crank and head, which I think makes for a more impressive powerplant. Next, the crank is lightened significantly by grinding the counterweights down in a crankgrinder, and also scalloping the front and rear cheeks of each rod journal. Stock 4.120" stroke is also retained. You could naturally do more modest modifications along those same lines and still get amazing power and torque without a lot of dinero spent. We used aluminum rods, huge roller cam, custom intake with (3) Holley two barrels, custom oil pan. You could use items more natural for street driving and be very pleased with your results. Just follow good machine shop practices such as bore and hone w/torque plates, and align hone the block, and that will give you a good foundation to start with....thanks for your interest!

 

PM sent.

 

Come on guys! less than 1 HP per cube? Certainly it is possible! Engine has a 2 inch intake valve. Head design is very similar to the mercedes sports cars of the 50s and 60s except for no overhead cam. You need about 125 cfm head flow and 9.6 to 10 to 1 compression to accomplish it. A decent cam and cam design alone has come miles since back then. Something around 235 to 240 duration at 050 and matching the heads best flow lift wíse. Test the head to see where flow stops rising and cam for that. I would use a hydraulic myself. Requires less duration for the same rpm (about 14 degrees less) and rpm range is below the point where solids must be used. (typically 7000RPM would require solids, below would not) Heads port reasonably well. Big carb required at least. Two would be better and three wonderful. ! hp per cube should be attainable in any engine with a little planning. Even the worst and these engines are far from being that. And I aint even a chevy guy but I have built a few. Even did one of these back in the day for a stock car guy.
Don

 

I think you can get to overkill on stroking a motor. stroking is more effective for low end torq than top end horsepower. the larger 6,s usually are stroker motors. boring gives you more for the buck, it usually has a rising HP curve, and the torq comes in hi early and doesnt drop till it runs outta air, which is more like modern short stroke engines.

 

That same engine ran 10.70's in a 3200 lb.doorslammer before it went 8.00's in a rear engine dragster! Its very possible and doable on a modest budget!

 

get yourself the chevrolet inline six cilinder power manual by leo santucci


regards,

bees

www.blazerbees.com

 

Everyone should look at that engine shop and their products, and , no, I don't know them, but I appreciate what I see, when I see it!

Traderjack

 

As you already seem to know,
the gearing can really wake up those sixes.
Those early 3 spds and 2 spds really wasted that tork.

I had a 3.20 rearend and a simple 4 spd saginaw with an early 235 (duals and fenton headers),
and man that thing hauled ass on the freeway pushing a big tank of a '50 suburban.
Wish back then the t-5 was around cheaper just to have that OD.

Good luck on that thing.

TP

 

My arguments against it are simple:
1. it's not cost-effective compared to many other choices (292 = more power for less money)
2. there are very few "do exactly what I did and you'll get these results" for the stovebolt, most are 50 years old. Far more R&D needed which may not be practical for this builder - there are 20 cams with approximately those specs, which one will work? Who wants to do back-to-back tests for manifolds (and I haven't seen a good manifold)?
3. 250 hp sounds like a lot compared to stock - but it's going to be boring before long
4. 261" & 250 hp pretty much ruins any "low speed torque" - the engine has to turn much faster to develop that power
5. if you want old, use a GMC 302
6. if you want a serious inline 6 use a Ford 300
7. after the money is spent and the engine isn't finished - then what?

 

For those that think 1 hp/cube out of a 261 should be no sweat, you're dealing with an engine that's got a cylinder head design that would be at home on a farm tractor. If making a horse per cube with these engines was a piece of cake, I don't think that the likes of guys like Wayne Horning and Harry Warner would have taken the time and trouble to design twelve port crossflow heads for them. Check out the 1955 HRM article about Frank McGurk working over a 261; they had to go to the ragged edge of streetability to wring 197 hp out of it. Even the 12 port engines in the best of tune made around 1hp/cube or slightly better, and that figure was usually obtained running on alcohol, with a camshaft that you'd get tired of very quickly on the street. I'm sure that the 197hp 261 that McGurk put together made for a lively street engine in the mid '50s----keep in mind that (despite what sort of bullshit figure the owner would throw at you) most street driven Ford flatheads couldn't claim an honest 200 hp.

 

As Don said (above) more power can be made today than they did then - the cam especially has progressed. The maximum venturi area that's "streetable" is also larger than before, far better valve springs etc.
In particular, I think the valve gear (pushrods, rocker arms and stands) were never researched out properly (all the older builds used stock rockers - and they're made of tin foil), and could stand much improvement. The stamped rockers are easily improved at minimal expense. I'm pretty sure someone with a lathe and milling machine could adapt modern roller-tip high-ratio rockers without breaking the bank.
It will still be an adventure rather than a build, because it may take several tries before you get the power you want, and testing is hard on the wallet, the clock and the parts.

If you have the money and the determination, go for it. The thing to avoid is that famously foolish "you didn't lose until you quit trying", which has ruined many stubborn people. If it can't be done, I want to find out before I spend dollar #1.

What would I do?
Video and record everything, including the parts that didn't work and why, then make a CD, a VHS tape and a booklet and sell it. I can't help with the content, but I can tell you a lot about how to organize and market it.

 

I have a 261 in a 39 chevy, and I dont know how it will run but I,m going to leave it in there just to be different. I mean how many 39,s do you see with a 261 these days. You may get there faster but you wont be the first one 'without' a chevy V8. gggg

 

just put a high performance intake valve in it and be done with it

 

If you're talking 261,they have forged rockers of reasonable strength for street use.GMC's have stamped sheetmetal rockers that are quite rugged.And for the 292,roller rockers are available.
250 hp from a 261 is possible for sure,just like the Flathead Ford V-8 ,how fat is your wallet?

 

Hey guys thanks for all the coments on this subject however Im not building a drag car here if i was i would put a 454 in it with 150 shot and call it a day.
What i want is a cool mid 50's type hot rod thats different. If all i can get out of the ole 6 banger is 200hp so be it.I was just curious what the limits were on the ole girl. As long as she has a loud rapp,can blare some "Johnny be good" and will smoke the tires when the red light turns green ill be happy. ;-) Rock-n-Roll Daddy o!