Chevy 250cid-->301cid



There's a fella over at who stroked a 250 by using a 292 crank and a ton of mods to produce (so far and I hope he makes it work) a working 301cid! Sounds cool too.

Yeah, Jeff was thinking about stroking his Poncho motor out that far with the 292 crank. A blown, 5.0L, OHC six.... that'd be sweet! 8)
Clifford used to stock OHC Poncho parts. Cutting down a Chevy Blazer 292 or GMC Truck crank, with a few other mods, sounds pretty cool. And the cam and belt issues for the 230 and 250 Cammer are all sorted now. The really good thing about the Pontiac and Chevy I6 engines are that they are very strong.

In Aussie and New Zealand we were stuck with GM Holden sixes, which could scream along very well but even with a Falcon 221 six cylinder stroker crank thrown in, they were never more than 235 cubes. Just like a Chevy six, only smaller.

Today, they are getting Toyota SC12 or SC13 superchargers or GT40 Garret blowers on these 179/186/202 engines. They are very cheap, and when something breaks, it very easy to get replacement parts easily. Not like a V8 or bent six.
What would be the advantage of swapping the cranks from the two motors? Does the 250 have a bigger bore than a 292? Amc guy just wandering.
No, the 292 GMC crank is just much longer in the stroke than the 250 Ch**y.

For example, suss out this donk.

This pickup is powered by an injected 1968 Chevrolet 292 Straight-six cylinder engine that has been overbored .060" for an actual displacement of 301 Cubic Inches. The truck is launched at 5000 RPM, shifted at 7000 and turns 6400 through the lights in the quarter mile. This vehicle is completely street legal and has current license and inspection and is occasionally street driven. It is raced mainly at street legal events.

AMC have support from Clifford I think, for a 291 ci stroker on the 4.0 and 4.2 engines. Shame there is no room for a longer throw crank in the 250 Ford. :cry:

:idea: Quess that's why we have 300 I6's in F150/250's :LOL:

The whole idea of worked long stroke sixes is the instant grunt off the line. V8's, even big blocks, have trouble matching any six in the 250 to 301 inch barrier off the line in a drag. 60 ft times are kick a** qwick!

Below is another shot of the "little" 292 powered pick-up that kicks serious butt See it on

Yesterday I talked to a guy I ran into at the WM parking lot. He was driving a really nice 69 Nova. It was white, had a slight rake to it and looked bone stock right down to the steel wheels and stock hubcaps. It had a 250/3 on the tree. He told me he pulled it home from the junkyard 2 years ago and has been working on it since. Future plans are a stroked 250 and a 6 speed. He says he has a whole garage full of Chevy 6 engines, everybody swaps in a small block and gives away the 6 stuff. Real nice guy, to bad he's a Chubby.
I have a 4.0 jeep motor that has the 258 crank in it, 280 inches. My point was what advantage is there in putting the larger crank in a 250? Why go to all that trouble? If putting the 292 crank in the 250 results in the same thing as having a 292 to begin with what is the point? If the 250 had a better block that enabled you to go with a bigger bore then yes, I could see the point. I guessing that the 250 is to the 292 what the 199 or 232 is to the 258. The 199,232,258 all used the same bore but with longer stroke cranks. The newer 242 [4.0], has a stock 3.88 bore compared to the older models being at 3.75. This is why many do the JEEP stroker combo.

It's done mainly because the 292 package doesn't fit in everything. The 292 is taller, has different engine mounts, and is heavier (not much). Ever seen a 575 BBC that looks like a stock 396? I've got one... :)

I've seen a couple go with some 1.88" honda rods, and stroke it even more (with an offset grind). That's a little much for me to get 6 more cubes, but some do it.

My OHC stroker will actually be a 4" bore by 4.125", giving 311 cubes. The crank is done, but I'm on block #2 in my search for a suitable victim. It looks like I'll be using a quart or so of Hardblock to help things out (or new siamesed liners). That project is on the back burner for now...
I am crazy about Fords, but those big Chevy 292 cranked 250's are bitchin'. In Australia, a Hilborne injected 311 was run in a little Torana (Pinto-sized car) and it would do 10's. It ran Ferra valves, alloy rods, HEI ignition and a short intake which was practically just an injector adaptor. The deck height was fairly low for a six, and it had lots of low end grunt mixed with a huge top end power figure.

The drag race guys like to trim down the external dimensions, and stroke the living daylights out of it. A poor rod to stroke ratio doesn't seem to lose much in a 1320 ft dash.
If you're crazy enough to pay for it, Clifford used to offer stroker goodies for the 300... With the stock 4" bore, we're talking 330 cubes here... However, To support that kinda cubes requires one heck of alot of headwork......
I believe that vato deserves a BRAVO!

That hometown set a goal with the goods he had and accomplished it :checks:

It does sound pretty damn healthy.

Cop a load of this from

Has 419 ft-lb's @4200rpm, and 377bhp@5200rpm, all from a 3.6 liter twin turbo. Car weighes in at 3650 pounds, but it does a 13.5 second quarter and 175 mph top speed.


It's a Lotus Omega, first introduced at the 1989 Geneva Auto Show and was produced in limited numbers until 1994. About 1100 Omegas were built in the years between 1991 when it entered production and 1994. Unlike other Lotus models like the Esprit, the Omega was not a homegrown model but instead a modification of someone else's work, the Opel Omega 3000GSi 24v to be precise, the top of the line Omega. At that time both Lotus and Opel were owned by GM, which felt that a special high performance model of the Omega was required to change its plain, bland image. The original engine, a 3.0L DOHC 24v inline-6, was enlarged to 3.6L, and two Garrett T25 turbos were added, along with a water-cooled intercooler ("Chargecooler" in Lotus lingo). The original 5-speed manual gearbox was substituted by a ZF 6-speed item, straight from the now-extinct Corvette ZR-1, with the deletion of the "skip-shift" feature found in the ZR-1. Apparently the gearbox was the only one GM could find that is capable of handling the Omega's massive torque. None of the Omegas are believed to exist in North America, and only 440 of the 1100 were built British-spec RHD.

Here is the Falcon XR6Turbo. It has just 321 hp, and 331 lb-ft, 3850 pounds, and a 14.0 second quarter. Boost is just 6 pounds. I think with 9 pounds of boost, it would kick the Lotus Omega's ass!

I don't know why I did that really. Guess I think that 300+ cubes of big Chevy or Ford I6 is pretty threatening.

Big block sixes Rock, whatever tha flava!!!!
On Fathers Day I met with members of the Southern California Chapter of Inliners International at the Irwindale Speedway(east of L.A.) One of our members has a '28 Chevy 4-door sedan, beautifully restored and mildly customized, powered by a 292 Chev inline 6 with a Jimmy(GMC) blower on top! It sure draws attention from all the "motorheads". Almost everthing that doesn't move is chromed. Anyone who is interested in inline engines(including orphans) should check out our car club( Most of our members (over 3000) build early and late model Chevs and GMCs, but there are full-house model-Ts,As,flathead Ford 6s, a 284CI flathead Chrysler 6 in an old Plymouth coupe, Buick 8s,and even International truck engines. Several years ago I saw Bruce Crowers son(Crower Cams) race a roadster powered by a 1932 Nash OHV straight 8 at over 200MPH at Muroc dry lake(north of L.A.). Everyone was impressed!
301 CI is nothing. When I was at Clifford's we built a 292 all the way to 331 for some guy back in the midwest. Now that was a kick ass motor. He was running it on a circle track.

I do not know if Clifford is still making or selling the AMC conversion kit with crank, pistons, rings bearings, etc. We used to make them and go up to 291 CI. Jack, Jay and I were working on a 302 CI version of that as well but due to circumstances that never happened and I do not belive will ever be a reality. Oh well.
I do not know if they are still doing the offset ground cranks to get the extra cubes. A lot of people, I believe, seem to feel the need to get over that 300 ci mark with the jeep motor. Too much $ for those extra 20 cubes. To me, especially in sand drags, those of us that run inlines must keep the motors under 291 ci or pay a BIG weight penalty. I had a 289 ci jeep motor but had issues with maintaining good ring seal. I believe that it was due to a thin cyl wall. So the stroker I run now is 280 ci that is going on it's 5th year with the worst cyl having 6% leakdown. So in the future I will bore again and get several years more out of it!