I am replacing the worn out 216 I6 in my 1948 Chevy pickup with a 261~ much like how the hotrodders back in the 50's would do it, so if I put a 4BBL or 3 carb manifold(which would be better?) on it, a set of headers, polished and lump ported the head, raised the compression ratio to around 9.5 or 10 to 1, and upgraded the ignition, what kind of performance could I expect? Oh, and I was wondering if anyone had any suggestions for a mild street cam and who to get it from? The truck will be a daily driver used for the occasional race with the guy down the road who thinks his little s10 with a plain 4.3 is all that because it has racing stickers all over it and has shiny rims.
i would go with the 4 barrel carb less problems to set up. about 450 cfm. you don't lump port the head on the 261. that is done on the 250-292 6's.
Why can't you lump port the head? they make kits to do so... And I'm wanting the most power I can set up a 3 carb with progressive linkage which will deliver 4bbl or 3 single bbl carbs
Show where you can buy a lump port kit for a 261? No matter what you do ,as in spending less than a fortune and using a slightly reworked stock head the HP will be limited to about 200.
Sorry, I'm just going off some stuff the guys over at the hotrodders website told me... I figure you should be able to squeeze at least 1 hp per ci from the old engines fairly easily... right?
If you want to hop it up like we use to do. Go with a 1953 235 power glide head, split the exhaust, use two carbs, a nice cam. You could also shave the head to raise the compression even more.
Those motors are limited by their head design, and that holds the rpm's down. Torque is their strong point, though. If you want to beat a 262 V-6 in a S-10 you're going to need a V-8 of some kind.
I was trying to stray away from v8's just because they're like rabbits~ if you have one you have ten and so on and besides, I like the rumble on an ol straight 6 Couldn't I use that famous low end torque and turn a higher geared differential?
200 hp is about the limit for a streetable 261. Patrick's Antique Auto sells a couple of decent cams. Google "Soup That Chevy". It's an article from 1955 that covers dyno testing a 261 with progressive modifications. At the ragged edge of streetability they made a hair over 200 hp. That was with boring, head work, cam, exhaust, and three carbs. There's a ton of great info in that article.
Wrong. You're working with a mid '30s design, and as much as I love these engines, I can't deny that the cylinder head design belongs on a tractor. Ford flatheads are in the same boat; the day you see one of them that makes 1 hp per cubic inch, you'll see an engine that's got several thousands of dollars invested in it. The only early Chevy/GMC sixes that approached that figure had Wayne heads on them, and ran on alcohol.
My 2 cents, 4 barrel looks really wrong on that engine. Might as well stick a 307 in there. Better performance and economy. 3 carbs will be a challenge from a tuning standpoint. I agree that 2 carbs will probably be the best way to go. I would suggest a pair of Carter w-1's or wa-1's. These have manual fuel circuits. Not as tricky to tune and balance. They use the small base, so you will need a 216 intake. You can also use a 235 intake. That will require you to weld up the carb studs and redrill to the smaller base. I don't recommend using the bigger 235 base. Carb selection is not as good. 3 carbs in progressive can work. You need to be darn certain you have clearance at the firewall before making that investment. Harder to balance. Looks great, tho. Carbking was recommending w-1's for this. 574s on the ends and a 684s in the middle. Haven't built one of these personally, so cannot comment on the performance. My builds have all been dual set-ups to date. Plenty pleased with the power, even up here at altitude. Tom
Last 261 we had on the dyno was 231 hp 296 ft lbs of torq. Motor cost 1600 bucks to build. It ran 2 holley 2 barrels. .080 over, ports were close to stock but we did have it on the wet bench. Good little motor and will piss off a lot of home built SBC. Plus it just sounds nasty.... Wayne head...oh boy cant wait to do that one!!!!
I have not built any 261 for many years. But I used to use a 3/4 grind from crane cams I think. You can build them so they will beat a s 10 or 265 V8. I beat many 265 V8's back in the day. The bigest problem with the old Chevs was they were hard to shift fast. I ran those engines in a 1951 hardtop, 1941 coupe, 1931 coupe, 1950 tudor. I have a Model A engine that will beat a 265. It will run a 12% grade for 1/10 of a mile at 9.48
The cam was hand made for us 200 bucks but well worth the cost(sorry it was billet but the good kind) It now runs a 6 speed that cost more than the motor. Hell i cant run a cell phone so video little iffy. I will see if we kept the sheet.The torque was way off from what we wanted so we wrote it off as a failure but it sure as hell ran good on the street.
Go to Inliners.com and sign up. Pay whatever the fee and get the article on the "Cadillac 261". It's a reprint from an article from their "12 Port News". The engine uses mid 80's caddy pistons and rods. The crank needs to be cut down. But all off-the-shelf parts. You end up with a stroked 261 at close to 300 cubes. Economical build yet torquey as hell.
To squeeze 1 hp per cub from that stone you will invest a small fortune. If you are going to invest a small fortune anyway then do what the rodders in the '50s that had a small fortune to spend did and put a V-8 in it. There were guys that drag raced 6 cylinders way back when and were pretty fast. But the GM guys used the big Jimmy and invested their kids college funds in them. Custom heads extreme cams injection etc.
If you can find one, both McGurk and Nicson made 235 intakes that were flanged for the small base 216 style carbs.
If you were old enough you would know we put V-8s in 50s cars because sears sold adapter kits for the caddy and the SBC was cheap.(i paid 550 for a 327 11 to 1 short block in 68) I really dont think 1600 bucks is a small fortune unless your on welfare. Milage , cool factor,and out rite nasty sound is better than most little blocks. Now a 454 small block gets my blood boiling......but no college fund here
That would make sense. They were the top of the trade for inlines and knew which carbs would work and which would not. Contrary to popular belief, large base Rochester Model B's are not strong performers. There are some large base Carter YF's that might be a better solution, but still using vacuum power circuits and their resulting coordination difficulties. Best to go with the small base Carters, Stromberg BXOV, or Zeniths.
English isn't your first language is it. I am old enough to remember the recession in the '50s. No cash ment that you dropped what you could afford in what you had. The big Jimmies that were running and breaking records were expensive by the standards of the day they belonged to professional racers. Now you bought a 327 short block in '68 for 550. I was working as a welder in '68 and my bringhome was 80 dollars a week. So even in '68 when we were supposed to be in good times 550 was a pretty good lump to spend. The boy was talking about doing it like they did in the '50s. I stated a fact. Your '68 reference is almost a decade away from the '50s. I also stated a fact when I stated that to squeeze one pony per inch from that trot line weight would cost him a fortune. I did go back and read where someone stated that for 1600 bucks they squeezed 131 out of one. That's just a little shy of one HP per inch. They were also taking Wayne heads etc. I don't know when the last time you bought a Wayne head was but you don't build one with a Wayne head for 1600 bucks unless you just get lucky. Now you are talking 454 inch small blocks, that's street rod crap. You are a street rodder right? Nothin' trad about a 454 inch small block, not to say that I don't appreciate one but it appears to me that you are suggesting he dump the 6 also, or else senility just sets in early in your family. You also threw in nasty sound and milage? A common non truth is that an inline 6 gets better milage than a V-8. Most of those old 6s do good to get 12-16, my small block gets in the neighborhood of 20-22 w/o OD and it does make more than one horse per cube.
I know Leo Santucci,the guy who wrote the hi performance book on the later 230-292 Chevy 6's. He started out drag racing 261 Chevy 6 cylinder.He said an all out drag race 261 with a seriously reworked head and cammed up beyond street use and 6000 rpm it what it takes to get one HP per cubic inch. That's a head done on a flow bench ,600 buck forged pistons for reliability and so on.Very expensive HP just like a Flattie V-8,you do it cause you like it,the cost isn't a consideration.
Another good piece of information is that a Stromberg BXUV-3 is the same basic design as a BXOV-2, but with the larger 235 size bolt pattern. A pair of them should work well on a large pattern dual intake.
I was warned about the high posters here but we have several 261/235 that are over the 20 mpg. Just looking around and found i was making 98 bucks on the farm fixing tractors and 60 bucks a week at the market.Selling frames out of tri five chevys at 75 bucks each and International scout frames for 100 to the circle track guys(guess you picked the wrong job) Oh well i was warned about the older(super high post counts) crew here.(one of the reasons i dont post here)Maybe go back to the original 261 post or start your own SBC post.
Or you can just drill out the bases on the 216 carbs so they fit on a 235 intake. Its not the much, put on a washer and you cant even tell. My 261 is running a factory split exhaust, so i had to use a 235 intake...... Wanted to use 216 carbs cause the ones off 235 ran waaay rich. Ive drilled out a few pairs now.... No problems.
Maybe I'll start a street rod post, you're down with that right? Ya know if I didn't like the boss I would suggest that you should have listened the warning and stayed home. But you should pay attention to the fact that you are the one that started flinging shit not I. As a rule its you short post new commers that feel a need to prove themselves by challenging someone that has been around for awhile. There have actually been a few that have gotten the corn combed out of their hair and turned out to be alright. In your case the jury is still out I'm afraid. Listen for the popping sound.
I have an old original Offy 3 pot intake with 235/261 sized intake ports with 216 sized carb stud spacing. Just for the record. I can also confirm the McGurk 235 intake with dual 216 carb spacing. Just traded it to my boy Delton who put two 235 sized Carter YF's on it with 216 sized Carter YF bases (they swap right out).
Even the later series Chevy 6's get to the edge of streetable at 1hp/inch, and they were a HUGE leap forward from the 216/235/261 motors. Definitely want to see the build sheet on your motor...video even better (as they say: pics, or it didn't happen). Maybe a dyno slip? Something. Truly, if you found a $1600 formula to build 1hp/inch old Chevy 6's, you oughta be SELLING that formula and revelling in your newfound wealth.
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