BBC Chevy Comp Cams 547/547 Xtreme Marine Retro Hydraulic Roller Cam 11-451-8
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BBC Chevy Comp Retro Style (flat nose) Hydraulic Roller Cam.
547/547 Lift 254/260 Duration 112 Lobe Sep.
Xtreme Marine or Street Rod Camshaft 11-451-8
This cam has a flat nose for use in early or late model roller blocks and non-roller blocks. We have this cam available in an oe step nose also in our other listings. The part number for it is 01-451-8
Part number: 11-451-8
112 lobe sep.
This cam is a popular choice for our street rod bbc engine builds.
Comp Cams 'Xtreme Marine & Auto' Step Nose Hydraulic Roller Camshafts.
Official Dyno report on our 505 engine with this cam choice, a single plane intake, Bravo heads, a Brawler 950 carburetor, and a MSD distributor.
Official Dyno report with this cam choice, Bravo heads, a dual plane intake, a Brawler 850 carb, and an HEI distributor. This cam produces an immense amount of torque in the low rpm range. We highly recommend this cam for applications requiring very high amounts of torque in the low rpm range.
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 step nose oe roller style for use with later model blocks or blocks with a provision for a cam locking plate.
Please read the complete ad before purchasing this cam. If you're not sure if this cam is correct for your application, feel free to contact us for technical support.
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