Inliners International Forums General Discussion Engines The stroker 261

Hi guys, this is my first thread so bear with me. I have noticed that a lot of people have been talking all over this forum about the caddy 261. I have a 1959 261 from a huge flatbead apache, and in the garage it sits. I have a 235 with an 848 head, and clifford headers, got rid of that God forsaken oil bath air cleaner, got a good aftermarket one, and I managed to get a 261 rochie carb with the bigger barrel, I have the stock rearend and like 3.90, or 4.11's, I have an old muncie 3 speed OD, and that thing cruises at like 2400 rpm or so at 75 MPH, its close ration so it kick butt, because of the perfect gear split, it's like having a 5 spd, 1st,2nd,2ndover,3rd, 3rdover, I run with most small blocks under 300hp. Not to get off topic, but the caddy 261, makes 285-292 cubic inches. What power can a stroker 261 provide over stock? what kind of power can a 261 stroker provide with triple carter weber 2 brls, clifford headders, and clifford 270 degree cam, .470 lift, and a highly ported/polished 848 cylinder head with high lift intake rocker arms, with bigger valves on both intake/exhause, all balanced with and HEI, looking for figures here, HP and Torque, don't be shy, I wont hold you to a said figure, just looking for ball parks here. thanks in advnace.

P.S. I have read every post containing the words 261 so I am not trying to be redundant. I love you guys posts, and I have learned so much in the past year, I just want to say thanks to all of you.

I must have pushed the "add reply" button too quickly. If you have checked all of the 261 posts you should have found the link to the 1955 HRM feature about Frank McGurk's 261/278 project. I would estimate that what you are planning on your 261 should provide another 10 to 20% more power. I had a couple of 261-powered chevrolets (a 1951 coupe and a 1953 2-door) in the late fifties-early sixties that could keep up with most 265 and 283s. my best build used an Isky E-2 cam, three Stromberg 97s, and a milled and ported Coervette six head, and a Corvette six exhaust manifold

Sounds like a great project. Keep us posted

Hoyt, II #922

Dear Mr. Debane;

The 261 built to 278 CID can make as much as 250 horsepower (normaly aspirated) on 'pump gas' and will rev to 5,500 RPM (safely). More can be had with fuel, NOS or using a turbo etc.

This engine built to 285" (Cadillac 6) or to 292" using the same "stroker" crank is limited to 5,000 however. This 'high torque' version is best used in vehicles (over 3,000#) for "street" use. This one is a great item for cars of the 40s & 50s as It's twice the Hp/torque of the 'stock' 85Hp 216 engine and bolts right in.

I don't believe there are any actual torque figures availabe, but you could check with Tom Langton to be sure.

I'm told he has a 'short block' for around $1,800.

Good luck.

Thanks for the replies, I did in fact read the Frank Mcgurk article several times over the course of the past three months. That being said, that engine was just a bored out 261, totaling 278 inches, he made 200HP, but he was using two single barrel carbs, an old style header, and technology thats 40 years old now. Would it not be safe to say that cams, carbs, pistons, rods, and exhaust have come leaps and bounds since then? would a stroke out not increase HP and Torque to a large degree? People at Clifford tell me no, Tom Langdon tells me yes. Because lets look at the physics here, and yes I have taken physics. You are increasing intake volume of air and fuel, then compressing it all into the same tight little area and igniting it. This increases preasure, IE-PSI, which gives a better and more potent explosion, which should result in increased torque for sure,and since torque and Hp and biproducts of each other, it goes hand in hand. Some things cant be gotten around, like the bad head design, but we should be able to maximize HP elsewhere, "Free up" if you will to crest that 270-280Hp and 350-370lbs/ft of torgue area. Sure the caddy 261 will rev about 500 less RPM on average, but its the 292/250 argument, the 292 works less hard to make the same amount of power, while the 250 must rev higher, work harder and use more gas to make the same power. Provided the two were built identical except their strokes the 250 would reach the same power as a 292 at a higher RPM. Just some thoughts, not to get off topic, but the topic was about the 261 stroker advantage with modern parts, etc... vs a non stroked, but bored 261/278, with 40 year old technology.

All the things I have ever read about stroker vs boring is that boring comes out ahead. First it allows more air into the cylinder because the cylinder wall is moved away deshrouding the valve. Second it comes with none of the increased frictional losses that stroking comes with. But in the end cubes is cubes and if you are not professionally racing it I would do what is easiest.