Inliners International Forums General Discussion Hi Performance 235 Cam Duration

I just bought the F298 cam from Patricks in the catalog it doesnt list the duration. I know I should have asked when I had them on the phone, but I forgot. Now I have a cam with a duration of 228.4 on the intake, and 229.7 on the exhaust. When I look in the Langdon catalog he recommends a cam with 254 intake and 264 exhaust. Would I notice a big difference between the two cams? I am running a 235 bored 80 over with an 848 head. Two BXOV-2 Strombergs and a split exhaust. T-5 Tranny with 4.10 rear gears. Who sells perforemance cams?

Thanks,
Dan

I just looked at cliffords cams. I am thinking about going with the monster 268 duration mechanical cam. Should I buy there cam kit? I have new lifters with my patricks cam, along with what they call competition springs and tubular push rods.

When comparing duration numbers, be careful that you're comparing apples to apples. Make sure both numbers are total duration, or duration at .050 lift.

Most cam grinders now give duration at .050 lift. This is an easier number to deal with as it's easier to figure out, when degreeing in the cam, where the .050 lift points are than where the valve starts to open, i.e. .001 lift. The valve doesn't really start to flow much air until it's .050 off the seat anyway.

I just checked my F298 from Patrick - it is 268 too (and 227@.050). so I agree, compare apples to apples. I think most of the "snotty" performance cams are about the same anyhow. I am going to use the F-298 in my next 261 with the lifters and pushrods he sent too. Patrick has always treated me right. My 235 runs like a top, so I took his advice on the 261. I wonder if this is a lot of cam for a 235, but on the other had, I wish I had guts to try it...

After calling Clifford I figured out that the Patricks cam will be fine. I dont know if it is guts of stupidity to throw this cam in the 235, but I will figure that out down the road. Now I cant decide if I should use the molly pushrods or steel ones. Patricks told me use the steel ones, cause it would be better to bend a pushrod than break something on the head.

With the gearing that you list, running the F298 shouldn't be a problem. It idles at about 750 rpms with a definite lope. I have one in my 261.
Considering the poor ratio between the intake and exhaust flow, I would think that a split pattern cam with more duration on the exhaust might be the better way to go, but I haven't tried it.

I had no problem bending the Clifford moly pushrod once on a stuck valve.
I can't confirm, but I would think that the moly ones are just lighter than the others, since moly is stronger than steel per a given thickness.

Since I already bought the steel ones, I think I will stick with them for now. What kind of things should I look for as a sign I need to use molly ones?I pulled a set of molly ones out of my old motor, but they were the short pushrods, and I need the longer ones for the new lifters.

hey Gearhead, what didn't you like about the F-298 cam in the 261? I have a 261 in the machine shop this week, and we will be starting in about 3 weeks to put it all together. That was the cam I chose. I figure they have been grinding them forever so if a guy does everything else right (carbs, ignition, trans, rear etc), you couldnt screw it up. Do you DISLIKE your 261?
Tom

I like it very much. Not sure I would like it with a 2.95 or lower 1st gear due to the loss of low end torque, which is why the vendors tend to steer customers away from this cam. If you gear it properly, you won't miss the torque. A T5 with the 3.50ish first gear and a rearend between 3:36 and 3:70 (depending on tire diameter) will work well for nearly everybody. The power is very even through the rpm range, but it may be a little less so with the 235. With 9-10:1 compression and a good set of mufflers, it sounds great.