It was said when I sunk my intakes, that I was giving away compression. I don't think I removed as much as the relief in those pistons. That being said, I would love a set of those pistons. I am currently running a McGurk roller cam. Warren
Just found this thread! Picking up two 261 cores in a couple of weeks. Incredible amount of information posted here over the years! Hope to replace my 216 in the roadster in a year or two with 261 built with a bit of attitude, something that mighta been found in an early 50s rod.
So on my way home pulling a UHaul box trailer. Picked up my two complete EBay 261’s, one with the full flow filtration capability, one without. Turns out the gentleman had a complete 848 head in the shed as well, that’s also in the trailer! Scored a 12v starter and generator, flywheel and bell housing for the engines as well. Pretty excited about it all, going to have to have to set this stuff aside for awhile as I really want to get the Pontiac roadster on the road this spring and the 216 currently in it runs well. I think all the bolt on speed equipment on my 216 aside the center bolt valve cover fits these engines, but as I’m intending to sell the 216 complete I’m going to be looking to acquire new parts for this engine. Carlisle swap next week, I’d like to find a triple single barrel manifold instead of the dual intake I have on the 216, I like the idea of a progressive linkage. Appreciate any thoughts! Al
Heathen, thanks for the info, I’ll havta find a set of those studs as I won’t want to steal them out of my 216. GasserSteve, I had the mistaken impression that all the manifolds for these stovebolts were the same. Proves once again why ass-U-me is spelled as it is. I’ll havta find the later model triple intake, did some research on the Speedway site and educated myself on the differences. Thanks! Al
216 intakes use small base carbs, 235 large base. For a triple carb intake, you'd be better to use a 216 intake with adapters, or machine it for larger ports. 3 large base carbs are way too much unless you've extensively modified your engine.
Al - if you put on a 3 carb manifold, consider NOT using progressive linkage! How many Austin Healeys, Jaguars, or other performance inline six cylinders engines can you find with three carbs AND progressive linkage??? Size the carbs to the engine, and use solid linkage. Jon
Jon, my thought was that with a centrally located primary carb and two secondary’s on the ends that the driveability would be better off idle. Back in the day had experience with two different tripower setups on v8’s, one a factory Pontiac unit the other a small block with an Offy and that’s how they were set up. Been over 40 years since I worked in a shop with jags n healeys and the occasional triumph, and I don’t ’member a lot of details but some of those I think were variable venturies like motorcycle carbs and not sure they all had common manifolds? This 261 will not b stock, hope to get the compression up to around 9 to 1 and put a decent cam in it so it has a bit of an attitude and a significant lope at idle. To your point, I do have a concern about driveability off idle, especially with a bit of a cam in it and hence my thought to use the center carb as a primary with progressive linkage? Al
The only way for you to know for certain is to try it both ways. If you do an honest set of tests, I am pretty sure how you will end up doing it. If we were still restoring carbs and building multiple carb setups (in 60 years, I built a few, still have a few dozen) and you asked us to do it progressive, we would have politely suggested that there might be others that would do that for you. The V-8's with tripower do indeed run better with progressive linkage than with solid (but never as well as a single 4 or dual 4's). Let us know how it turns out. Jon
I'm hoping to fire up my GMC with Rochester Tripower soon. I modified a stock GMC manifold with 5 1/2" carb spacing so I could use off the shelf linkages etc. If it's too much carb, I'll switch to 1bbls, either Carter W1s or Stromberg BXOVs. I can't see how fuel distribution is any worse than a single 4bbl that a lot of guys are running successfully. A guy down here that has run a GMC dragster for a number of years thinks the small base 2bbls won't be enough carb. I figure they flow about the same as 5 x 97s. My thoughts are the same regarding running progressive 1bbls with secondary carbs, but that will require a lot of mods including making thicker throttle plates for the secondary carbs. I have a 261 I want to build someday, although a bit milder than this GMC.
The Jalopy Journal
