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Mr. Vizard: thank you very much for the information. I am looking forward to your write-up of the aluminum heads. I am using a set of 325cc Dart Pro 1 heads on my BBC bracket motor (60 over 454 on methanol with EFI). They were installed "out of the box", with no porting - I had to replace a cracked heads and was in a big hurry to get back out to the track before the season is over while keeping costs to a minimum. Interestingly, they out performed the old heads right out of the box even though I lost a full point of compression (from 13.5 to 12.5:1). Peak hp on the chassis dyno did not change, but there was a consistent 30-40 hp and torque gain in the middle. The car is ~0.1 seconds quicker in the 1/4 mile. The old heads were a very nicely ported set of 325cc rectangle port OEM castings.
In the off-season, I am going to get the heads ported and milled to gain back the lost compression. Do you have any infomation you can share about Dart's CNC porting?
I know you have always emphasized cost-effective modifications in your writing and I really appreciate that. It is much easier to make hp by just throwing money at a problem, but less interesting and for many of us is not an option anyway. A number of years ago a buddy built up a SBC pretty much following the advice you published. That was a great bang for the buck motor. Spent about $2,500 and it made power like a crate motor of nearly three times the price. We were pretty proud of it, though really the credit goes to you.
Richard
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