CARTER RBS or AUSSIE HEAD?

[Anonymous]

Thanks for looking—I’m soon going have to decide if I want to do something about the asthmatic performance from my ’76 250. The tranny’s coming out, and so I might as well do any engine work at the same time. I can stick with the stock set-up (Carter RBS) and keep buying high octane or convert to an Aussie head, two-barrel and headers (but with the stock cam).

When I run high octane through my RBS, the engine runs damn smooth (except when it vapor locks on 110 degree days in Phoenix).

Does the Aussie head give that much more pedal power?

What are your thoughts?

67 Mustang coupe—Granada 250, O/D tranny, & disc brakes, 68 Cougar rearend, 81 Fairmont drive shaft all installed with my English teacher’s hands and Craftsman tools.

 

[MustangSix]

On a completely stock 200, just bolting on an Aussie 2V head with a 350 Holley and headers will net you an additional 30-35 horses at the rear wheels. A very big improvement. On a 250, the gains shoud be similar.

But the 2V heads are not cheap, and with a similar chamber size the CR will be the same, requiring you to run the same fuel.

With a Granada 250 you should be able to run regular fuel. The CR should be no higher than 8.0:1. You may just have a tuning issue.