My computer crashed over the weekend and while reassembling my data files, I found this one. The table below shows all the airflow numbers I've run across over the last couple years for Buick 350 cylinder heads. The PAE ported head numbers came from the Hot Rod article, Jim W's numbers are from his thread. I think the stock references (Stock and Stock #2) came from the same places, but honestly I didn't write it down. Also on the second row of data you will see the numbers for the heads I purchased from someone else on the board. Ultimately, those heads were a Level 3 port job by Greg Gessler. In an e-mail conversation, Jim W. mentioned that Greg never used a header flow tube when he tested exhaust flows, so he suggested I make a correction of up to 10% of the flow. Since doing that on the low lift numbers would produce exhaust number higher or equal to the intake numbers, I used lower correction factors there and stepped them up until I reached the 10% correction(at lift values of 0.500 and above). Keep in mind that all these numbers were developed using different air flow meters so can't be directly compared. I would say that it appears that Jim Burek, Jim Weise and Greg Gessler all got to about the same place. When I find the numbers for the flow balanced intake manifold, I will post those also. PS when I type the numbers in, everything lines up. When I submit the actual post, that's when the spacing issues start. If someone else knows a better way to post these, please let me know. Code: Stock Burek PAE ported Jim Weiss Ported Lift Intake Exhaust Intake Exhaust Intake Exhaust 0.100 66 44 66.7% 74 55 74.3% 66 55 83.3% 0.200 119 93 78.2% 135 110 81.5% 131 105 80.2% 0.300 169 124 73.4% 187 145 77.5% 188 131 69.7% 0.400 198 128 64.6% 241 167 69.3% 229 141 61.6% 0.500 198 130 65.7% 243 176 72.4% 255 167 65.5% 0.550 251 178 70.9% 0.600 254 181 71.3% 256 170 66.4% 0.700 263 171 65.0% Stock #2 Gessler Ported Corrected Lift Intake Exhaust Ratio Intake Exhaust Exhaust Ratio 0.100 58 44 75.9% 62 59 95.2% 60 96.1% 0.200 116 91 78.4% 122 106 86.9% 109 89.5% 0.300 158 118 74.7% 183 132 72.1% 140 76.5% 0.400 180 127 70.6% 226 146 64.6% 158 69.8% 0.500 188 137 72.9% 248 154 62.1% 169 68.3% 0.550 250 157 62.8% 173 69.1% 0.600 189 139 73.5% 250 161 64.4% 177 70.8%
Here are the intake airflow numbers. I include the average, standard deviation and the balance of flow numbers. The last of those are directly from the sheet Greg provided to the prior owner of the intake, I have no idea how it is calculated. This was on a TA Stage 1 350 intake. I don't have any stock comparables.
Very interesting! One thing to remember is that CFM flow is only part of the equation... Many other aspects effect the actual performance... I'm sure your heads will work awesome by the way...
Someone correct me if I'm wrong, are all Buick heads the same, flow wise? If I remember the later late 70s heads had bigger exhaust valves, memory is a little fuzzy on the topic.
In comment to those numbers and power production if you where only running a Cam of .550" lift then the heads with the fatter flow numbers at .300" and .400" lift would make the most power, this assuming all of the Intake ports where within 8 % of the minimum port area between each other, and the chosen Intake and Carb whether not the choke point.
There is no confirmed answer to this question however I have looked at the various castings and they are different over the years. I am taking a set of 68, 70, 71, 73 and 75 heads to be flow tested and then I will have real data on which year exactly the heads lost the flow numbers. I do know that the 75-80 heads flow badly compared to the 68-70 heads... BUT the real question is which year did the head flow decrease. I need this info for my book.
The newer heads (75+), much like the newer blocks, had more iron in them and so the passages didn't flow quite as well, but you can still make them perform with the correct components. They're less prone to cracking and give more material to work with. I see no downsides to using them, and would actually prefer them myself.
Ok , I'am game! So what does a Aluminum block have to do with what's being talked about in this thread?
Maybe he meant the Aluminum heads? That is why I posted this thread. As a reference point when they do hit the market.
That should happen soon they have been working on it for a long time now. My ported head I got from TA flowed 235 intake and 176 exhaust. I sent my heads to them in 1993.
Awesome! I have a '70 (SP Motor), and my blue '76 and I'm looking forward to those tests. Also, gonna buy that book for damn sure.