Genesis 427 S/O- Should I be Pleased?

[What'saCobra?]

Lots of good ideas and comments on this thread.

Perhaps the best advice above is to live with the engine for a while and see how you like it. It surely has lots of torque and must give a nice kick in the pants from that many cubies. Rick is likely correct that the car is quicker than you are, so a little on-the-job training might be in order anyway. Most guys lose it in the first 30 days, if they are going to do it and it is frequently at large throttle openings.

Unless you either have a minimum HP guarantee opportunity or a ready $4-5K, i would wait before making too much of those numbers. Drive it a while. There is a lot to be said about torque and keeping the parts together.

But, i would expect that the heads/manifold combo is the biggest oppportunity for improvement, along with the street muffler. Likely you don't have documented head flow numbers on your particular set of heads, because they would probably not look so good, unless the heads were seriously CNC'd, rather than just a clean-up. We all tend to under-report less than glowing numbers. There would have been no reason to flow test stock or near-stock heads. It takes time and money that is only of value if you are either developing something new or the builder is required by contract to verify head flow pre assembly. Otherwise, simple inspection and careful assembly will be sufficient for most builders for any known 'stock' combinations.

You might consider asking the builder what he would suggest. But, there is nothing really wrong with what you got for the money, since the street mufflers are good for 30 hp loss or so, pretty easily and 500hp isn't terrible at all.

i wouldn't jump all over the cam thing, unless i was satisfied that the heads/manifold combo was optimized for those cubes, which isn't particularly likely.

The open plenum/sinble plane manifold comment above is quite valid, but it will not be easy to get that 3310 to meter correctly at the low velocity rates of low rpm and large open throttle combinations with the bigger plenum. With that many cubes, low fuel flow from an old carb design with cause lots of carb spitting and even backfires. Very exciting and might necessitate fire protection under the hood.

Steve is correct that you might move up to an 850 pretty easily with all those cubes, but again, geting a larger 3310 to flow correctly will be harder than the 750.

i simply cannot overstress the excellence of new carb designs and their utility at wide-open-throttle and low rpms, particularly Holley's HP series. The old designs require huge accellerator pump systems to make up for lousy metering sensitivity at low airflow velocities. It is a drivability problem, not a horsepower problem. Once there is enough rpm, and enough flow velocity, the old systems work fine and dandy.

Stay away from 7000rpm like the bubonic plague, though. Short shift, particularly in the bottom two cogs, to avoid errors, particularly if your tranny is new and/or you are not currently high-seat-time qualified...

Break it in, not up.

And please don't put one of those puny small air cleaners in a turkey pan. Skip that pan expense and hp loss. Only turkeys belong in turkey pans, that's why they are so called. Screw style. Go for power.

Here is a suggested filter combo. It is 3" gasket to gasket and a minimum size for this 351. You should consider 4". Yes, there is a little fiddle (dremel tool cutting) necessary to clear the MSD distributor, which distributor i also consider nearly mandatory on anything decent. You could consider the K&N top filter cover, if you can't get 4" under your hood (i can't quite either), but it ain't cheap and only a dyno test would tell if it is worth the money on your engine.

In summary, bigger is much better. Look at the filter assembly under the hood of any NASCAR 358 incher. Huge and then some. OK, 8500 rpm is different than 6500 rpm, but you have 100 more inches to feed.

Anyway, good luck.