Lookt at the build on my 455, and am thinking about using the XE274 from Comp Cams per a recommendation. Can anyone tell me how much chop, if any there is in the idle? I noticed on Comp Cams website they recommend a 2200 stall converter and headers.

The second question is will a set of RA cast headers or the long branch headers be sufficient. Personally I'm not a fan of regular headers as they always seem to be more of a P.I.T.A. then they're worth.

Thanks!

If you're talking about the 230/236/110 version with .52/.53 lift...I am running the roller version of that cam in my new 468. Lope is not too choppy at all...very reasonable. I was surprised. The flat tappet version may be a little more aggressive sounding.

I'll attemp to post a video.

I've got the XE274 in my 400 with KRE aluminum heads, RA long branch manifolds and a 2400 stall. It definitely has a lopey idle. Not too bad though. Just enough to shake the car a little while you're sitting at a stop light and let the other drivers know you have a beast under the hood.

Steve G, the additional 68 cubes will suck up alot of the lope of the cam as compared to the 400.
Sprech's 455 will likely do the same.

Sprech, check out my video under Ramblings, "new engine, again"

Bronze Bird sounds almost the same as my 400 with the XE274 and KRE heads. Are you using Magnaflow exhaust?

I WANT TO HEAR IT TOO!!! Actually I do want to. I am gathering info for a build that I am going to have done next winter and the cam is one of the most difficult to choose. I want aggressive but not too much, almost on the lesser side so I can hear my tunes if I choose. But usually more choppy is more power and if I am spending a ton to get all the go fast goodies but get too little cam then it is money out the window.....sigh.... can you see the battle going on in my head....


Jason

Not necessarily true. The choppy idle comes from valve overlap, mixture and timing tuning, as well as duration. And there is easily such thing as too big as well. Either it will put you out of useable powerband, or in the instance of stock heads, exceeding a certain valve lift above where port flow stalls, you're going to see very little power improvement even at the top end.

Doesn't make sense to get 5hp on top to loose 50ft-lbs on the low end. Or have a cam that's going to peak power out at 6500rpm when your shift point is a 6000rpm. Or trying to come out of the hole with 2.73 gears. The whole system (all the engine components, the gear, torque convertor if applicable) all has to be matched.

Let me give you a story based on true life from a few years ago. Two co-workers, I'll call one Mr. Big, and the other Mr. Science.

Mr. Big, of course always went big. He built a car with the help of a fellow "go big" guy.
Engine 540ish ci Chevy BB with roller cam exceeding .7", Holly Dominator, 14:1 compression (not kidding, he probably could have run diesel, lol), aftermarket heads hogged to the max with over 400cfm on the intake, and huge Flowmaster exhaust. Rest of the combo was 4000 stall covertor, 4.11 rear gears, 12x33 slicks, with a line lock. He rarely drove the car on the street (super loud, sucked race gas by the gallons, anything above 50mph will drain you.)

Mr. Science built his as essentially a pro-tourer in the true sense. Handling, braking, comfort, and power. His was a 400ci Chevy SB 0.30" bore. He picked his heads not only based on flow, but as runner volume to ensure good velocity, and considered the combustion chamber. He injected it, and had a roller camshaft that probably didn't exceed .55" lift. Compression was about 10.1 and the car would use 91 Octane no problem. He carefully chose all the components of the engine right down to the 3" exhaust with crossover. Trans was a T56, and gearing was 3.73s. He would switch to 15" drag radials when he went to the track. Idle was definitely not stock, but still smooth. Keep in mind the suspension was dialed in for handling, not for maximum 1/4 mile traction.

One day, we had an outing and both came. Mr. Big had to tow his. Mr. Science drove his. To keep the story short, Mr. Big was running 11.20s, Mr. Science 11.50s. Only .3s difference yet Mr. Science hadn't even the right suspension. His car you could drive across country and get over 20mpg on the freeway (he measured it several times driving 30miles one way to work where most of it was freeway). His was also more reliable (Mr. Big was always breaking stuff). BTW, both of these were on the motor only, neither had nitrous installed.

If I had to choose one of the two cars to own, it would be hands down Mr. Science's.

Bronze can you post a link to your CE274 here. For some reason I am not allowed to use the search feature?

I have a 400 YZ with #16 heads, being rebuilt. Cast 9.8:1 pistons, everything else stock but bore is .030" over, and I am using ARP rod bolts with appropriate machining. Gear is 3.42 and 4 speed trans (M22).

I like either the XE268, or XE274 for Comp cams. I also like the Summit 2802.

It would be nice to hear the XE274 and see if I like it.

Thanks

Here yo go...

Thanks. That sounds great.