The Stovebolt Site Forums The Shop Area Engine Shop More cam than I thought?

I fired my 235 that I built for my truck today. I put a hydraulic cam from a 261 in it thinking it would give a little boost and still idle smooth. Well the smaller displacement must make the cam feel bigger because it idles with a considerable lope. The carb is all good and vacume at idle is 15",and wow is it responsive even a little to jumpy for a daily driver mabey. Has anyone experienced this ? A 261 hyd. is 222 deg. at 0.50 right?

I thought 261's had mechanical cams, at least the stock grind since it was used exclusively on trucks. If correct is this an aftermarket cam?

In Canada the hydraulic 261 cam is more common as there were many more Pontiac cars with the six than big trucks.

A 261 cam ,solid or hydraulic is no where near 222 degrees duration at .050 lift.The Howards M4F ,206 degrees duration at .050 lift is slightly hotter than a mechanical stock 261 cam which I believe is around 190-200 degrees at .050.Factory cams were usually rated at .004 lift,the "advertised duration" giving far longer duration figures than .050 lift.
235's with a 261 cam have a barely noticable lope to the idle,sounds like you have some other issues contributing to the racey idle.15 inches of vacuum is low even for a typical 3/4 cam.

The cam is a Canadian hyd. Pontiac 261. I drilled the idle air bleed in the carb and it smoothened out alot. Still has a little lope to it. It just needed a little more fuel at idle and off idle i guess. 15" is pretty good when you live at 4000ft above sea level.

IT SOUNDS LIKE YOU MIGHT BE A GOOD SOURCE OF WHAT SOME OF US
DOWN HERE ARE LOOKING FOR; A TRUE 261 HYDRAULIC CAMSHAFT WITH
LIFTERS. WOULD YOU BE WILLING TO GIVE US A CONTACT FOR SUCH
AN ITEM. THANKS...

I think Canadian supplyers like Elgin have long since stopped grinding replacements. The ones I have are used ones Ive held on to, I think there arent that many around anymore. My cam grinder could probably make one for you. I measured my spare today It has .352" lift at the lobe. Im not sure of the dur. but 204deg rings a bell.

My FLAPS tells me he can get both the solid and hydraulic grind. When GM engineers put a 261 cam in a 235 they also added a cast iron dual exhaust manifold along with a 3 carb sidedraft intake. Does your engine have similar breathing characteristics?

Its just got stock manifolds with a Carter for a Can. 261 on it right now. I will swap my home built headers and triple Offy intake on once its broke in. The head has considerable porting and a 3 angle valve grind 8.5:1 comp. Should drive nice.