NC Engine Builder
Grumpy Old Man
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No destroking allowedAt 8.5lb/ci, a .030 over 383 with a 3.25” stroke (374”) would work well at 3200lbs.
Use some 915 heads on it.
No destroking allowedAt 8.5lb/ci, a .030 over 383 with a 3.25” stroke (374”) would work well at 3200lbs.
Use some 915 heads on it.
I understand the "historical" aspect, but
I understand the "historical" aspect, but why not a W2 head instead? Just curious
And they allow aluminum heads with a 100 lb penaltySeems like that just depends on how they want to interpret it.
The factory heads with offset rockers weren’t available in 1967....... so they’re def splitting hairs a bit saying TA are legal, W2 isn’t......especially since you could be running big runner Dart heads on a Chevy.
Just so I’m clear on this....... you have documentation from “back in the day” showing the reworked Mullen’s heads flowed 83cfm@3”??
I have to believe that a set of ported X heads flowing in the 280 range would pass tech..... no?
Because of the TA head , I can run these like you noted !Correct, My BAD! It's even listed as a T/A head (DOH ). The ones indeed known for offset pushrods and rockers for port enlargement. The heads on this thread use a W2 rocker and have a more extreme pushrod relocation than the T/A head. According to the MP manual, the T/A offset rocker does not have as much offset as the W2. But, indeed, damned if that bench doesn't make me think of a mainframe computer the size of a wall mount bookcase that might have the computing power of a T.I. handheld scientific calculator....
That's big block ruleNo destroking allowed
Last years superstock chapion was a big 63-65 Plymouth wagon, 440 with two inline four barrels.
Open a cover on that huge bench, and there’s a mouse running on a wheel inside to power it up.
View attachment 1715640563
My home built flow bench said 296 cfm at 10 in of water and .600 lift with a 4 in tube. The difference between .450 and .600 was not a lot but the flow ramped up very fast. How this compares to others I have no idea but that is a ton better than any other head I flowed.
Its 100% possible my numbers are wrong, I am no professional at using a flow bench. I can say they were consistently higher than my unported W2 Econo heads that flowed 268. What suprised me was .600 Lift was only 3.42 cfm better than .400 lift.I’d like to see the flow sheet on that. By my math your head would have to flow 494 CFM at 28 inches.
Its 100% possible my numbers are wrong, I am no professional at using a flow bench. I can say they were consistently higher than my unported W2 Econo heads that flowed 268. What suprised me was .600 Lift was only 3.42 cfm better than .400 lift.
I’m mostly looking at the test pressure. Are you sure it at 10 inches and not higher? I’m not one of those guys who think every bench (even home built benches) should read wildly different. That’s why I’m asking. Do you correct for ambient temperature and barometric pressure?
I opened the exhaust port to achieve max flow with no restriction. On this day that was 344CFM. I set the head on my pipe. I opened the exhaust port to 10in of water in the tube while at .600 lift and wrote down my percentage. 86.5. 86.5 of 344 equals 297.56. Then I closed the valve to .500 readjusted the port to 10in and wrote down the percentage. 86. 86% of 344 is 295.8. I did this all the way to .100.
My numbers on the intake side were. This was with no clay on the port. When I added clay the numbers went up about 10CFM across the range.
.600=86.5 86.5 % of 344=297.58
.500=86 86% of 344=295.84
.400=85.5 85.5%=294.1
.300=79 79%=271.7
.200=73 73%=251.1
.100=52 52%=.178.8
Like I said, I am no expert but that is higher than the unported Econo W2 I checked by a good bit. I did not write that number down but I want
Mongo interested !!!
Impressive !I opened the exhaust port to achieve max flow with no restriction. On this day that was 344CFM. I set the head on my pipe. I opened the exhaust port to 10in of water in the tube while at .600 lift and wrote down my percentage. 86.5. 86.5 of 344 equals 297.56. Then I closed the valve to .500 readjusted the port to 10in and wrote down the percentage. 86. 86% of 344 is 295.8. I did this all the way to .100.
My numbers on the intake side were. This was with no clay on the port. When I added clay the numbers went up about 10CFM across the range.
.600=86.5 86.5 % of 344=297.58
.500=86 86% of 344=295.84
.400=85.5 85.5%=294.1
.300=79 79%=271.7
.200=73 73%=251.1
.100=52 52%=.178.8
Like I said, I am no expert but that is higher than the unported Econo W2 I checked by a good bit. I did not write that number down but I want to say 258-260 was that number.
I’m pretty sure he means the heads were flowed at 10”, and the 296 is the flow converted to 28”.
So, they should have been 177@10”.
Some of the flow bench kits/plans for home made benches have electronics that automatically convert whatever test pressure your flowing at, and display what the flow @28” would be.
.
100=52 52%=.178.8
Close to 300 cfm seems reasonable for this head with 2.02/1.60. Just depending on what can be done during the seat and guide work, it's going to be interesting to see what 7mm stems and possibly a 2.055 (if it's not an excessive risk of cracking the head) intake valve will do.
How are you determining that the flow range is 344cfm.....@10”?
344cfm...... @10”............. is 575cfm@28”.
If you aren’t applying any kind of correction to go from 10” to 28”....... then I agree with YR in that your numbers don’t agree with......pretty much the rest of the world.
296...... @10”...... is 494.9cfm@28”...... and I’m pretty confident in saying those heads don’t flow that.
Sounds like maybe you could use a few PTS test plates.
I’m not sure what size valves are in those heads, but even if it’s a 2.08”....... [email protected] lift is 188% DC.l(if you assume that’s at 28”)....... in other words...... not possible.
But, you’re saying that’s the observed flow @10”, which would be
298.9cfm@28”, at .100 lift..... which is 316% of what’s possible.