Quote:
The Racer Brown cam you have looks like it has 238 degrees intake duration at .050". The 260 H is 212. A big reduction.
238 degrees isn't a big cam for 500". I would expect it to pull well from 1800-2000 RPM and hit its sweet range from 3000-5000 RPM. It may be a little sketchy accelerating below 1800 RPM with a manual transmission. I wonder if there are some other issue affecting driveability as others have posted. What are the drivability issues? Was the carb swap done to improve the situation?
If you can post some more details it may help.
The cam does indeed spec out at 238* @ .050 on both intake and exhaust. Valve lift is .485 for both. The centerline is actually 105* with a lobe separation of 108*. I have a surging issue at cruise (about 1500-2000rpm), absolutely no power to pull from a stop unless bringing the RPM up and slipping the clutch, that I thought might be caused by the six pack. I then changed to a TM7 and a 750DP carb and still had the same issue. Pulled the MP tach drive distributor in favor of a stocker. Problem got worse when the vacuum advance was hooked up. Set initial at 5* from the original 15*. Helped a bit. Changed the carb to a 650 Eddy. Same thing. Notice that most of the cams out there have a recomended centerline of 110-112*. Therefore, my question about advancing the cam. Looked at Cadillac 500" engine cam recomendations (longer stroke but about the same cubes). MTS series 5 cam is recomended by a Caddie builder as having a peak cruise RPM of 2200-2500 RPM and specs at 208/215 @ .050 and .495/.510 lift. Thing is supposed to have nearly 600ft/lbs @ 2500. That's what prompted my question about the Comp 260H. I just want to be able to take advantage of my large displacement and not "shake, rattle, and roll" at idle.
BTW, I'm sure that it is obvious that camshaft technology is not my area of expertise. If you gave me a dollar for all I know, I would owe you money.
Last edited by rbstroker; 09/07/11 09:19 AM.
