Aussie vs. 4V Cleveland Heads

the aussi heads are smaller wo they will yield better low end performance which is more ideal for street use, if your on the track and keep it above 3 grand than use th 4v heads.

Since nobody has answered yet, I'll tell you what I can. While I have both, I haven't yet mounted my Aussie 2-V's, but have researched them a lot and built them already. Everything I have read and heard says they're MUCH more torquey for street. Technically, you could use a 4-V intake, but the Weiand Xcelerator (2-V) single plane is probably one of the best. Technically, you could use 4-V headers, but they won't scavenge as well (Larry Stock's 2-V Hedmans come highly recommended). I suspect they don't flow as well at very high RPMs, but your intake and/or valve springs, etc. may also be limiting factors there. Should all be good thru at least 6500 if built well. Err on the side of flat pistons, even hypereutectics, 10-11 C.R. There's a good web site on the differences; I'll try to remember to e-mail it to you when I find it. A guy I'm considering for some port work built & ported Aussies for a GT-40 & said they're "the best." Probably not for sustained 8000s, though. Good luck.

I would go with the 2v heads. 4v are just all out race head designed for high revs and big CID. If you port out the 2v, it will out perform the 4v for most applications. My ported 2v heads flow over 300 cfm which is 20+ cfm more than the 4v heads. The important fact about the 2v head is the fact that they keep the velocity up!!!! Very important when trying to race!!!!

i understand that 4v quench heads will work *very* well, even on the street - *if* you use the stinger port plates w/them. these fill the dead-spot on the huge ports, substantially increasing velocity, w/no reduction in total flow. this is what i will be using on my mildly-built engine. desktop dyno sez 460-475hp (+/-5%). for my engine build specs, see steve flier's thread on compression ratios/octane ratings...