Aussie Heads
Thread Starter
|
New User
Joined: Feb 2012
Posts: 24
Likes: 0
Aussie Heads
Does anyone have Aussie heads with a stock bottom end? I built a 400 a few years ago this way, and just recently found the time to install it, fire it up and drive it. I've been running 100LL avgas through it, since I had a few barrels of it from work. It loves that stuff. After doing some research here I see aussie heads with stock bottom end are not detonation friendly. Anyone have this setup and know if its possible to run 92 non-ethonal fuel or anything? Or will I be filling up at airports from now on? I think the cam is a lunati with .508 lift or something like that FWIW.
Senior User
Joined: Mar 2008
Posts: 149
Likes: 0
Aussie w/ stock bottom end
The problem that I've ran into with these heads is that the static compression is really high running 133052 (single pattern 228@0.050 & 0.550" lift) CraneCams. My pistons are 4.030" w/ 4cc intake valve relief flat tops w/ 0.055" deck clearance. My measured cold cranking dry cranking pressure is over 220psi. If you want to run these heads some consideration needs to go into your static and dynamic compression, and suitable cam selection that will be less forgiving on detonation.
Link to very user friendly static/dynamic compression ratio calculator:
United Engine & Machine Co. Incorporated
Theoretically ideal DynamicCR is 8.0:1 & should be able to run on pump gas, I'm 800ft above sea level, have 9.5:1 StaticCR, and have had no trouble with detonation using 93 octane Shell, the only fuel trouble that I have had has been stock fuel pump supply(and suspected lifter pump up) above 5500, and am seriously considering running a slightly larger solid for my drag race only app.
Link to very user friendly static/dynamic compression ratio calculator:
United Engine & Machine Co. Incorporated
Theoretically ideal DynamicCR is 8.0:1 & should be able to run on pump gas, I'm 800ft above sea level, have 9.5:1 StaticCR, and have had no trouble with detonation using 93 octane Shell, the only fuel trouble that I have had has been stock fuel pump supply(and suspected lifter pump up) above 5500, and am seriously considering running a slightly larger solid for my drag race only app.
Last edited by BrutalBronco; Feb 12, 2012 at 07:53 PM. Reason: changed "ideal StaticCR" to DynamicCR"
Senior User
Joined: Mar 2008
Posts: 149
Likes: 0
Yeah that is one of the disadvantages of using the stock rods, and stock bottom end. I know it's losing torque since the piston is so far away from the combustion chamber, but it's not noticeable in the seat. Additionally, I've learned to use a quality head gasket.
Thread Starter
|
New User
Joined: Feb 2012
Posts: 24
Likes: 0
Do you have this setup?
Thread Starter
|
New User
Joined: Feb 2012
Posts: 24
Likes: 0
What cam would you recommend? I have a lunati with high lift, low duration, that's all I remember.
Trending Topics
Senior User
Joined: Mar 2008
Posts: 149
Likes: 0
cam recommendations
It's been said that making a camshaft recommendation is like seeing a dentist by mail. I'd need to know your vehicle weight, final gear ratio, tire size, piston design & deck height, intake, and favorite color - j/k on the color I'll guess blue. I can tell you that these heads with 4cc valve relief flat tops with the 133052 CraneCams http://www.cranecams.com/product/car...detail&p=23840 shaft is entirely too conservative.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread Starter
|
New User
Joined: Feb 2012
Posts: 24
Likes: 0
Ok figured out which cam I have. Lunati truck avenger with .508 lift, 260 advertised duration, duration at 050 lift 210, lobe seperation 110. Intake and exhaust appear to have the same grind. Ad says 1,200-5,000 rpm power range, but I find the engine loses power around 4,000.
Senior User
Joined: Mar 2008
Posts: 149
Likes: 0
Cams rpm range usually typical of a 351cid engine. 400's have a tendency to perform at 400-500 rpm less than advertised on cams, especially when directly compared to a 351cid engine. Next issue is cam timing. It does seem like your cam could use an advance in timing relative to the crank to keep the power in the advertised powerband of that cam. Of course, this will sacrafice a bit of low-end grunt, but that cam should rev, with plenty of power, to 53-5400 in a 400, even with a stock intake and pistons.
Senior User
Joined: Mar 2008
Posts: 149
Likes: 0
as a last resort...
It would be wise to measure the timing of your cam, and then evaluate the next modification, pun intended. Before tearing the engine down the than chain, use a paperclip or close pin to make certain your secondaries are opening http://www.holleytv.com/video/11341, then evaluate your ignition, and ignition timing curve.
Thread
Thread Starter
Forum
Replies
Last Post
FORDMANMATT
1973 - 1979 F-100 & Larger F-Series Trucks
10
Nov 8, 2013 06:50 PM
mudslingur
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
7
Feb 25, 2009 08:53 AM
mositso
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
6
Oct 10, 2005 08:12 AM
Kruse
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
8
Jun 19, 2004 04:19 PM
