I recently aquired this BBB cam and would like to build my 455 to be able to use it effectively. The cam card reads as follows: Straightline Performance 233/244H12 Intake Exhaust Lobe Lift .0338 .0338 Rocker ratio 1.55 1.55 Valve Lift 0.524 0.524 Adv Dur 282 301 Dur@.050 233 244 Lobe Centerline 108 116 Lobe Separation 112 I'm planning on .030 overbore, edelbrock heads, roller rockers, and SP-1 intake, TA Super comp 2" Headers. I'm stuck on what pistons to get and what compression I might need to run this cam. I would like to run pump gas 91/92 octane if possible or is this cam way to much for this? Will a Holly 780 w/ vac sec feed this thing? Is there anything else I am missing that I might need? Its going into a 79 skylark 3300/3400 lbs with a th400 for Bracket Racing. Should I use this cam, is it right for this combo or should I purchase one better suited for the combo listed above. Ok BBB Motor Gurus.....Any help???
That is a Scott Brown cam. Very good cam. Go here www.finishlinemotorsports.com Geof or Bobb will know more about this cam than anybody. Deck the block, run about .040 quench, good forged pistons and you should be able to run unleaded premium. Need about 10 to 1 compression ratio. With the Aluminium heads you can probably run a bit more. Actually a "bigger" cam is easier to run on street gas than a small cam. Forget the 780 vac secondary carb. Run at least a 950 HP. I run Bigs CNC 950HP(flows about 930 cfm) and that is about as small as you want to run. You need big carbs with Buicks and the SP-1 works best with mechanical secondaries. Also if bracket racing you have much better throttle response with the mechanical secondaries. You should be into the low 11's with that car if you can get it to hook.
With 10:1 compression and a 108 ICL, you will have a Dynamic compression ratio of 7.75. Should be no problem with pump gas especially with aluminum heads.
Sounds like a very good cam, but you might want to look at the valve lift measurements again. They can't be right uzzled:
Quench is basically the amount the piston is down in hole at TDC + the head gasket thickness. A quench distance of .040-.045 gives the best resistance to detonation. Being that most head gaskets are going to be around .040, Zero decking the block is the best way to achieve that. As far as pistons are concerned, take a look at www.taperformance They offer very nice forged pistons. I would get a set with valve reliefs to avoid any piston to valve interference issues. What you need to do is choose a machine shop to use. When you bring all your parts to the shop, you will also tell them what static compression ratio you want. They then measure everything, and advise you how much they need to deck the block/and/or heads in order to achieve that compression ratio.
