254/260 duration

112 lobe sep.

This cam is our most popular choice for our street rod bbc engine builds.

Comp Cams ‘Xtreme Marine & Auto’ Step Nose Hydraulic Roller Camshafts.

Cam info:

This cam is one of our official cam choices in our line of bbc engines. It is the perfect size to offer the best balance of power while putting a relatively low amount of stress on the valve train. It makes a great amount of overall power on bbc street rods. This cam is somewhat aggressive yet suitable in 496 bbc engines or larger. It has a very aggressive nature in the smaller 454/468 sized engines and would require around 11:1 or higher compression ratio, but becomes more manageable in the 496 or larger builds. Compression ratio in a 496 engine build would need to be 10.5:1 or higher to yield decent results. This cam would be considered outstanding in a 540 and up to a 572 street rod build. Around 10.2:1 compression ratio or more would be all that is needed to obtain great results on these larger engines in a street rod. 

This cam has a unique profile. Our former cam used in our 555 engine was nearly identical in lift and duration and had a 110 lobe sep, and it made approx. 35 hp less on every combo we ran it on. Our new Comp cam is setup with a 112 lobe sep, yet still makes so much more power, and with the 112 lobe sep, creates a safer setup overall for the engine than a 110 lobe sep.

This is an amazing cam in every respect. As you may know, there are many aspects to a cam’s profile besides lift, duration and lobe sep. and Comp Cams has produced an excellent cam that works very well in all bbc street rods. We’re going to list below our actual dyno results on every size of bbc engine we have dynoed with this cam. We have used it in at least 600 bbc engines, from a 496 up to our 632 in the past couple years. Of the three Comp Cams we use, this is our most popular by far. 

We offer two more amazing Comp cam profiles that we’re very proud of. For those running the smaller bbc engines or lower than normal compression ratio, we recommend our one size down cam (566/566 lift) for improved low end response if you’re building a 454/468 engine. Even then that would be considered somewhat aggressive, and would require compression ratio numbers in the low to mid 11’s to operate well. For those building a 496 with approx. 10.5:1 comp. ratio or more, and want the decent bottom and mid to top end power available in a hydraulic roller without having to spend huge amounts of money to stabilize the valve train, then the 566/566 cam would be the better choice for you. See our other listings for these cams. Should you be running a 454-468 engine and have compression in the low 9’s and below 10.5:1, then we suggest the 547/547 lift Comp cam in our other listings. 

This cam will allow safe operation of the valve train without spending a huge amount of money on valve train components. It’s not going to give any problems in the long run if you’re running decent hardware and lifters. You must run a higher than normal grade lifter such as our Max Effort Series. This increased lift and duration will bring the spring pressures up on the nose somewhat high, and that’s desirable to maintain valve train stability.

Our regular Howards Tie Bar hyd. roller lifters were on the verge of valve float at peak power rpm on the smaller bbc engines. As you may know, the smaller cubic inch bbc engines will require a bit more rpm to make max power, and right at 6000 rpm, the regular street tie bar lifters were allowing light valve float to enter the picture. This is evident on the dyno, as the engine takes a sharp nose dive right about 5900-6000 rpm.

Truth is, prior to this rpm, the hp numbers were not climbing the way they should, and minor valve float was taking place earlier than 5900. Valve float to a minor degree can allow a valve to come loose from its locks. This could spell instant doom for your engine. It would be fair to say that most dropped valves in bbc engines happen when the rpm is taken past the valve train limits.  Each time minor valve float comes in, it is weakening, or may we say, creating excessive wear on components that eventually lead to a dropped valve.

We have many allies against such problems, and without spending a great amount of money, including the lightweight PBM Competition valves, and Comp Cams light weight springs and retainers we use in all our bbc heads. We also use high quality lightweight roller rockers. Read below for more info on things you can do to prevent problems in the valve train when running cams in the upper lift range. If you think you can get by with a slightly smaller cam, we offer a cam that is identical in its overall design but has a slightly lower lift, 566/566, and a slight reduction in duration. It would be better suited for the 496 pump gas street rods in our opinion, and is less demanding on what type lifters you use. 

The 575/575 cam in this ad would be considered max size you could run on a normal pump gas 496 build, providing you had at least 10.5:1 compression and a set of heads that were 320cc or more. There is a point that larger than needed cams will not produce more power but leave you with less street manners than the smaller cam. 

We also offer a third cam choice in our lineup of bbc street rod cams. It has a lift range of 547/547 and even less duration. This is the most practical size cam for 454 and 496 engine builds that are put in heavier cars and sport trucks. This size cam offers the best street manners, and valve train stability is excellent. It’s fair to say that 90% of our customers that choose a cam for their particular build end up with a cam that’s larger than needed. 

Listed below are a few important solutions to preventing valve train issues while having maximum performance and longevity in your engine when running large lift cams.

The solution to running a hyd. roller cam of decent size in a bbc engine is an easy, low cost fix, thanks to the Howards Max Effort lifters and Comp lightweight springs. The cost is only slightly more than the regular Howards street tie bar lifters, and they are undoubtedly the most stable hyd. roller lifters on the market without going to all out racing hyd. lifters. The Max Efforts are also very quiet. Not sure what rpm range they can remain stable at, but we have pushed some of our bbc engines up to the 6500 rpm range in order to establish the fall off point of a particular build. Fall off on hp levels are gradual up to 400 rpm past the max hp rpm range when using these special lifters, and that’s the way it should be. We now use these lifters with all three of our bbc cam choices. 

The next big cause for valve train instability when running a cam in the upper lift and duration range on a bbc engine would be having spring pressure that is too low. Regardless of what some may say would be the correct spring pressure, we know what it should be for safe operation and good performance. The numbers are slightly high, according to some uninformed authorities, but running too low of a spring pressure will assure valve float when running a cam of this size.

If you have weak springs or wrong pressure ranges in your setup, then you must correct this. We offer a proper set of Comp valve springs that work perfectly with this cam. They do not require unusually long valves. We’re very satisfied with the seat to nose ratio. These springs are also much lighter in weight than previous springs we have used, and that’s a real plus when trying to stabilize the valve train on a bbc engine running at near or above 6000 rpm. 

As you may know, there are larger lift bbc hyd. roller cams on the market, and we have used them for those running Pro-Street setups. Those also require a different type of lifter and special springs than what is used when running our regular Comp Cams. Our experience is vast on how to properly setup your valve train, due to the fact we have dynoed so many bbc street rod engines.

Big block Chevy engines pose a problem when running healthy sized hyd. roller cams if the valve train is not setup properly. It is essential that you address this before you start your build. 

We also offer this cam in a retro roller style for use with early model blocks.