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HybridZ

Went shopping...


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Today I took delivery of Brodix Race-Rite oval-port aluminum heads for my big block Chevy. The heads were milled to 110cc (need to check to make sure), with CNC combustion chambers and springs for a mechanical-roller (245 seat, 580 open). On my 461 (0.030â€-over 454, otherwise basically stock shortblock) I hope to reach the “magic†500 hp at or below 6000 rpm, with a torque peak of something like 550 ft-lb at around 4000 rpm. Perhaps. The exact numbers aren’t important, but they are nominal goals.

 

Other parts include Isky Red-Zone lifters and a SA Gear adjustable roller timing set. The cam gear can be rotated to give +- 6 degrees (retard or advance). I also got the Comp Cams steel roller rockers. Still undecided on whether to get a fancy multi-piece timing cover. And still undecided about the cam; it’s probably be from Cam Motion, which Pete Paraska recommended a year or two ago (yup, it’s been that long!).

 

The heads came from a protracted, agonized decision-making process. I REALLY wanted to buy the AFR oval-port heads, but AFR still has no plans to bring them to market, despite advertising them on their web site. The next smallest-port alternative from AFR, 305cc rectangular-port heads, is doable but probably offers no midrange advantage on a 461 over the Brodix heads, and might even have a low-end disadvantage. If I were smart and bought a forged 4.25†crank, decent rods and higher-compression forged pistons, the performance envelope of my engine would have shifted enough that the 305cc AFRs would have made more sense. But as it is, the Brodix heads should do fine; they are reputed to outflow any heads of comparable port volume (and hopefully comparable port cross-sectional area!), at least on the intake side. The exhaust side could use some help.

 

The Brodix heads are reasonably well-built. There are minor imperfections where the machined areas meet the raw casting, but that’s to be expected. Next on the menu is trial assembly to check for some tolerances, then ordering the cam and a checking-pushrod to check for more tolerances, and finally the custom-length pushrods (block was decked).

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Expect your torque to come in earlier, 550 is not hard to do for a 454, but it usually occurs much lower, say 2500-3500. (from what I've seen). I'd chop 1000 rpm off both those numbers for a more realistic goal, the big block does not need to rev high, you don't want ti to because it has a larger rotating mass.

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