Inliners International Forums General Discussion Engines hypothetical benefit of 292 v. 250

I know that the 292 can be built to take higher RPMs, but it seems that that takes lots and lots of $.

Was wondering from a more stock standpoint what would make more sense for a basic affordable novice race engine out of either. Seems to me that the 250 would be able to handle higher rpms in the more stock format with the shorter stroke. The fact that they can use 307 pistons also seems like a benefit. It also makes sense that they would get more benefit from a larger cam due to the smaller displacement (ie. 292 cam in a 250). It also seems that they should be able to take the same sorts of internal modifications that the 292 would take to gain horsepower (ie. lump ports, smoothing, crank mods, 194 head, decking, etc).

I know the weakness in the 250 is the front head bolt hole and that it is suseptable to cracking, but all things considered, wouldn't it make more sense from an economic point of view to go with the 250?

I'm only asking because I hear stories of the low rpm limit of the 292. I recent scored a 250 for very cheap that I am stashing away for a future project. I'd like to eventually get involved in some racing, either drag or landspeed. Wondering if it is worthwhile to stay with the 250 or if a upgrade to the 292 is really necessary to be competitive in a I6 class. I'm am completely ignorant to the racing classes at this point so if I am making assumptions, I appologize.

I know they always say "no replacement for displacement". But mechanical strengths seem to come into play and make you consider the benefits/drawbacks.

Given my experiences with the 292's,I also have seen and had much experiences with the 250 and the Champs that have raced them! I think you will be satisfied with whichever size you choose. One of the single most expensive costs in a 292, is the rod and piston combo. Since you either have a stock rod or custom aluminum or billet steel as a choice($$$$), that makes this portion of the engine package a little higher than for a 250. There is an 6" H-beam steel rod available for the 250(reasonable cost) that puts more economical rod and piston choices in your grasp at much less dinero. So that would be one financial advantage for the 250 vs. 292. Most any other mod from this point would have about the same cost for either,"lump" head, cam, intake,etc. The 250 will also be a little lighter than the 292, if that is a consideration as well. You probably should select a HP range as a goal and see which one will be the most feasible to try and obtain. I know a 292 can make 612 HP, but isn't very practical for anything other than all out drag racing. A 250 can modestly make 375-400 and be fairly reliable and have good longevity. High RPM isn't necessary for either one, but does show they can do anything a V8 can do and have the same results.

if you keep the rpm's on the 292 limited to 5k or less the engine will do well. so for the tq increase the 292 is the winner.
the 250 will certainly rev higher before harmonics start.

how radical of a engine do you want? a 250-300 hp 250 or 292 is not very street friendly. turbo it and you have a different story. tom

why would a 300hp 292 be not street friendly?

feller managed 300hp and a chit load of tq from a ford 300 with a cam not much larger than stock and 9.5:1 comp. perty street friendly, maybe you need a ford engine.

oh-oh,,,,you said the "F" word. LOL

MBHD

When Sissell was still alive, Hot Rod mag did an article on his company, and featured a 450HP 292 engine that he said was very "streetable", and easily obtained without roller cam or real exotic components....

inline300,
i do have a ford engine. its even a turboed unit, but it burns diesel and is in a 4WD.

i am saying a 300hp 292 is almost 2 times stock rating. thats like saying a 500hp smallblock is streetable. sure people do it. lets take that setup and drive it like a street car. stop and go traffic, highway. high heat. you will find it aint so streetable.

to get back on his topic though. twisted has only run the smallblock 6's and the hotrod6 from fla runs the smallblocks too. he winds his up nice and tight. and they move! harry stirnamen runs a 292 and is in the 9's with his turboed 37 chevy. tom

Trump mentioned his primary goal was going to be race oriented with whichever he chose, so I doubt he will be concerned with street issues or driveability. He said drag racing or land speed as his intention for it.... I think if you look at it from the HP per cubic inch aspect, its only slightly more than 1 HP per cubic inch, and a 350 would be 350HP in comparison, instead of based on original HP from the factory, and the increase of that. Most any engine can easily make 1 HP per cube and not have any adverse effects from it for street use.

This all gets down to definitions. If 6500 rpm is high, a 292 can handle it without huge dollars. If you are thinking 8000 rpm consistently, you probably want the shorter stroke motors.

If you are worried about setting sanctioning body records (SCTA, NHRA) plan on big dollars and in some cases like some NHRA superstock classes, 292s are not allowed as they were not car engines. If you want to drag race and set Inliner records, your motor choice will depend on which class you want to hit and the weight of the vehicle the motor is going into. If you just want to drag race in the inliner class or classes, the ones I have run have all been bracket racing and ultimate performance is not needed to win.

Most fast guys in Brazil run the 250's for setting records.
Turbocharged 250's making 1100-1400 HP range & the fastest car has a record of 8.2 or 8.4 in the 1/4 mile.


MBHD

In the land speed racing neither the 250 or 292 will get you in a special class. They don't qualify as "vintage". You'd run with all the rest. I have a Ford inline, it's in my tractor!

My 250 ran a 583/607 lift mech.(3800-7200rpm band) over 12.5-1 m20 3:08 gear when it was on the street Most of it's 17plus yr life before I started running mostly on th etrack and changing rear gears from a 3:70 then a 4:56 final was a 5:13 (I got 16mpgs city with the 3:08 gears) and drive that car everywhere.
work ,track IT was a daily driver. And Yeah I'd buzzed the Hound
out of it. Many times to 8000. When i had the car on a dyno the motor was right around 15-16 yrs old and It had pulled around 320 at the rear.

Was that with a factory head, or one of his '12 port' heads (since Sissel sells a 12 port non cross flow Ally head for the 250 / 292)? Didn't Sissel used to make a 'cheater' head for the old chevy I6 (235/261). Looked stock on the outside, but was actually aluminum, and flowed quite a bit better? Could it be he snuck something like that by Hot Rod?

Cause a fellah that is as clever as he was, would never try and pull one over on somebody. (that's good natured sarcasm there)

I think this is on topic.

300 hp is 2X the factory rating of the ford 300. It used a mellings tq cam (mild as it gets as far as aftermarket cams go) 9.5:1 comp ratio (pump gas friendly), idles like a stocker, got 17mpg in a truck (daily driver), there is no reason why this combination wouldnt be considered street friendly, dyno'd 300hp and right at 400tq at the crank....why couldnt a 292 accomplish the same thing?

500 hp street friendly, naturally aspirated, modern day small block, isnt out of the realm of possibility anymore.

I think this is on topic.


300 hp is 2X the factory rating of the ford 300. It used a mellings tq cam (mild as it gets as far as aftermarket cams go) 9.5:1 comp ratio (pump gas friendly), idles like a stocker, got 17mpg in a truck (daily driver), there is no reason why this combination wouldnt be considered street friendly, dyno'd 300hp and right at 400tq at the crank....why couldnt a 292 accomplish the same thing?

500 hp street friendly, naturally aspirated, modern day small block, isnt out of the realm of possibility anymore. [/quote]

X2 MBHD

[/quote]

Was that with a factory head, or one of his '12 port' heads (since Sissel sells a 12 port non cross flow Ally head for the 250 / 292)? Didn't Sissel used to make a 'cheater' head for the old chevy I6 (235/261). Looked stock on the outside, but was actually aluminum, and flowed quite a bit better? Could it be he snuck something like that by Hot Rod?

Cause a fellah that is as clever as he was, would never try and pull one over on somebody. (that's good natured sarcasm there) [/quote] It was an aluminum head, but they were emphasizing it was "450 streetable HP"! I met Kay briefly in the summer of 84 when he visited our race shop to discuss the "lump" head that was on Cotton's 292, and marvel at its awesome performance. It was at that time Sissell's most crowning achievement with any "lump" head he had done up till then. I got to pick his brain about many things for that short time he was there, and learned a lot about his "lumps" and other things....real nice guy to. Its a shame we lost him shortly after that.

X2 MBHD [/quote] I agree, its been done too many times before with great success! I also think that comparing the 300 HP 300ci engine to a 500 HP small block was not an apples to apples comparison. Engines have always been compared one to another based on HP per cubic inch, and a 300 HP 300 is more accurately compared to a 350HP 350. Comparing them based on factory HP ratings skews the results, because some engines are greatly under-rated, and some are over-rated. A 500HP 350 is equal to a 300 making 1.428 HP/CI or 428HP! Which can pretty easily be accomplished with the components available today. And as we have seen, turbos or superchargers ups the possibilities even higher for 6's. I've seen 600HP on a 292, but its on the ragged edge NA, but with forced induction, 600HP is more reliable and has a longer life span. The possibilities are endless....

Attached is a link to an older thread which contains a link to a 250-292 article.

I think a 250 is the better way to go, even though I have raced 292's from day one. I feel the 250 has a better bore to rod ratio to make hp. A lump head would better suit that displacement also. A 250 has a power band like a small block v8. Parts like blocks and cranks are easy to find.

Now, with that being said a 292 will make big power too. It takes more specialized parts to make them work. For the novice builder like me, it took some dyno time to figure out where the power is in these motors. I'm not saying I have it 100% figured out either but we are closer to it.
A 292 is like a 800ci v8. A small bore w/a large stroke on the crank. These motors do not like to rev or rpm.

My .02 cents Steven

That's pretty much my thinking on the situation. Seems like when I was building my 292 it was harder to find parts since some were different than the 194,230,250 parts (ie. water pump, side covers, etc). Seemed like the 250 parts were easier to come by and cheaper in most instances. I like the fact that the 250 can take the 307 pistons... that makes things more affordable. It also seems like there's a lot of guys out there making big power on the track with the 250s. A lot of them putting forced induction to them also. Kind of leads me to believe that they had a reason to stick with them instead of investing the time to track down a 292 to dump money into.

There's a lot of useful info in this thread. Thanks. I think I'm more confident in my decision to pick up the 250 for a future project. Now I just have to find something to put it in......

In theory... the Rev limit on a 292 is because it has a longer stroke. Therefore, the Feet Per Minute the piston is traveling is more because the stroke is longer. That is everything I know about Physics.
Of course in Theory... If a Frog had wings... you know.