NicD said:Ahhh...Good point...I'd never considered that before...Make perfect sense though...
So i guess my options are to
(a) build a 302/306, which shouldn't have the same problem getting fed by the smaller blower or
(b) Would i experience the same problem with a 331 that i would the 347?
(c) sell the 1.5L, get the Blowzilla and continue my pursuit of the 347.
The 302 vs. 347 should be about -40hp if I'm not mistaken, so that's not a huge loss i guess, especially for a daily driver that still stands to be well into the 400hp range...And my heads and other bolt ons would still work...
Either way I'd be better served to build a Dart block vs a stock 2 bolt right?
Also, any references for a relatively cheap Dart or R short block?
The thing that needs to be kept in mind is that twin screw blowers are positive displacement super chargers, meaning that it displaces a specific amount of air per revolution. Pressure is just a byproduct. Even a 306 built up to flow a lot of air (i.e. large heads, cam, etc) can tax the smaller blower. The 1.5L was setup to feed a stock 5oh with restrictive heads, exhaust, throttle body, and so on. You will top out the 1.5L at around 450 HP regardless of the rotating assembly that you have beneath it. If you plan to make significantly more power than that, then consider upgrading to a Blowzilla. If not, there's really no reason to spend the extra cash on a Dart. I just spent about $2k on a bare Dart block. That's about the going rate. The Ford 4 bolt block from what I understand can be had for about the same or a little less money but requires a considerably larger sum of money to get machined. Fix yourself on what kind of HP you want to make and between Rick91GT and myself, I think we can help recommend a good blower/engine combo to fit the bill (assuming you want to stay with a twin screw). For centrifugals, there other folks here on SN that can help you better. My personal preference for street centrifugals is Procharger.