aussie 400 rebuild

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Nov 25, 2003 | 07:19 PM

#16

danlee

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From: Delaware

dsmith_78,
I couldn't find either of those cams, but based on the adv durations with 110 degree lobe seperation and 110 intake center line, I get IVC of 58 degrees ABDC for the XE 256H, and 61 degrees ABDC for the XE 262H. If the intake valve is delayed a couple of degrees then the IVC will be slightly later.

I used the same specs as above and get 3.28 DSL for a 400(?) with the 58 degree IVC. The DCR for the 58 degree IVC is 8.4:1. You should not use this cam with those heads.
The DSL for the 61 degree IVC is 3.21. The DCR is 8.23. This is marginal for 93 Octane with no quench.

These figures may be different if the IVC is later, but I would consider another cam, or different heads.

If you have enough money, the look at the 185cc heads from CHI.

http://www.chiheads.com/

They have 64cc chambers.

Nov 25, 2003 | 07:55 PM

#17

Brian S

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Comp cams dynos

I didn't find a 256 or 262 either, at least not for a 351C. I found some SBC dynos for several of them. I would think the lift would be different but the durations should be close or the same.
http://www.compcams.com/information/...ts/DynoSheets/

Dan, can you link to the chamber collage in the file area on my home page? There are a lot of comparisons and Aussie heads variations I want to talk about. I can't get the link to work properly.

Nov 25, 2003 | 08:14 PM

#18

danlee

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From: Delaware

Brian,

Here is the link, but they have to get a yahoo ID and then sign up for your Cleveland Group.

http://f1.grp.yahoofs.com/v1/IAnEPwj...erCollage1.jpg

I can't get it to work either, but if you move the collage to the picture area, it should work.

Try this:

http://photos.groups.yahoo.com/group...c=gr%26.view=t

Last edited by danlee; Nov 25, 2003 at 08:37 PM.

Nov 25, 2003 | 08:51 PM

#19

danlee

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From: Delaware

I found those two cams for a 429/460. the XE256H has an IVC of 55 degrees ABDC and the XE262 has an IVC of 58 degrees ABDC. That is because the intake lobe is advanced to 107 degrees instead of 110 degrees. This will add to the DCR. I would NOT use these cams with 58cc heads.

Nov 26, 2003 | 05:29 AM

#20

dsc

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From: Maryland

OK. When I Look at the big picture I think it would be a better to go back to the stock heads get rid of the Aussies and continue with the conversion. This will be a daily driver. How about changing the cam from the 272 to a 268, would I gain anything?

Nov 26, 2003 | 07:49 PM

#21

danlee

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From: Delaware

dsc:

A Crane 523921 (266/280) has an IVC of 64 degrees ABDC. The DSL is 3.13", and the DCR with 58cc heads is 8.05:1. That should be OK with 93 Octane.

That should produce 443 ft-lbs torque@2500 RPM and 330 HP@4500 RPM. This includes a dual plane manifold 600cfm carb and headers.

The Crane 523931 (272/284) should produce 433 ft-lbs torque@2500 RPM and 333 HP@4500 RPM.

I have been using a Crane H278-2 for a while with 351C-4V (63cc) heads and flattop pistons and it is OK with 93 Octane. It has a noticable lope at idle and the gas mileage is about 8 MPG. Mine is not a daily driver however.

If you go back to stock heads and do some work on the exhaust ports, and use the Crane 523921 (266/280), you will get 415 ft-lbs torque@2500 and 304 HP@4500. You will have a DCR of 6.77:1 and be able to use 87 Octane.

You should be able to use a RV type cam with the stock heads and improve your gas mileage, but your performance at higher RPM will suffer.

A hydraulic roller cam can give you good fuel economy, low RPM torque and good performance at higher RPM, but there is more expense involved.