[mysticmissle]

looks like holley discontinued these? does anyone know if its because its difficult to tune, which may be reasonable or because its impossible to tune junk and bad for the brand lol
holley 550-528 is what i am referring to

[krisr]

Am tuning one of these 2x4's right now. The motor was previously supercharged with a 6/71 but had nothing but overheating issues so went back to a naturally aspirated tunnel ram combo just for the street. They tune up fine with hyperspark control but because this engine has 3" spacers under the TB's, the fuel curve is a bit wonky compared to say an LS fuel curve just from the delay of fuel leaving the TB before it hits the valve on stuff like decel events plus the tunnel ram has interesting characteristics in the fuel curve around 1800-2200rpm that needed working out.

The engine would be perfect with a single sniper, but my mate loves being different and he's not interested in running on the ragged edge of performance. As long as it drives nice (which it does insanely good now) he'll be happy.