Lack of bore notching on big $$$ engine builds
02-27-2018 | 12:05 PM
#1
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From: SF Bay Area
Lack of bore notching on big $$$ engine builds
This may be a stupid observation, but as people post pics of their big money builds I’m not seeing much bore notching happening. It’s seems like easy HP with no drawbacks, so I’m surprised to not see it on every refreshed/built engine. Am I missing something?
02-27-2018 | 08:26 PM
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My head guy that bore notches my 454 blocks says that the valves are unshrouded enough on 4.5" bore and don't benefit from it. But, on a built 454 that has good heads and air flow he has seen 20HP on the dyno. He pulled the heads on the dyno, notched the bores and made a few more dyno pulls. These are not 330's these are more 600Hp 454's.
02-28-2018 | 10:31 AM
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That that makes sense as high end builds typically have high end bores (huge) and no reason to compromise the block. I imagine it more important on a N/A 454 than a blown 540+ monster.
Thats some secksi stuff there!
Since I’m refreshing my 502 I’ll ease over some notches in it since I’m there. It already perfectly imprinted the gasket pattern with a light shade of carbon for me. Lol
My head guy that bore notches my 454 blocks says that the valves are unshrouded enough on 4.5" bore and don't benefit from it. But, on a built 454 that has good heads and air flow he has seen 20HP on the dyno. He pulled the heads on the dyno, notched the bores and made a few more dyno pulls. These are not 330's these are more 600Hp 454's.
Since I’m refreshing my 502 I’ll ease over some notches in it since I’m there. It already perfectly imprinted the gasket pattern with a light shade of carbon for me. Lol
02-28-2018 | 06:48 PM
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From: ALTO, MI
Just make sure you don't grind down into where your top ring is going to come up the bore.
On a 454 it makes a big difference. On a 502 or 540 it helps enough to make it worth it to do.
Anything bigger in bore size I wouldn't do at all.
I have done this myself to all of my engines up to the 598. On a 4.6 bore there isn't much between the cylinders so I don't want to make it even smaller.
On a 454 it makes a big difference. On a 502 or 540 it helps enough to make it worth it to do.
Anything bigger in bore size I wouldn't do at all.
I have done this myself to all of my engines up to the 598. On a 4.6 bore there isn't much between the cylinders so I don't want to make it even smaller.
03-01-2018 | 01:16 AM
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Just make sure you don't grind down into where your top ring is going to come up the bore.
On a 454 it makes a big difference. On a 502 or 540 it helps enough to make it worth it to do.
Anything bigger in bore size I wouldn't do at all.
I have done this myself to all of my engines up to the 598. On a 4.6 bore there isn't much between the cylinders so I don't want to make it even smaller.
On a 454 it makes a big difference. On a 502 or 540 it helps enough to make it worth it to do.
Anything bigger in bore size I wouldn't do at all.
I have done this myself to all of my engines up to the 598. On a 4.6 bore there isn't much between the cylinders so I don't want to make it even smaller.
03-03-2018 | 09:07 AM
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From: chicago
Biggest issue hindering airflow is typically valve shrouding on a bbc. Alot of heads have chambers designed to fit smaller bores, like a 4.250 bore. Especially an issue when you get into 2.25+ diameter intake valves.
Also, I am willing to bet bore notching would show bigger gains when tested with a stock like 26* valve angle head, vs say a 24* angle or shallower head with a better canted angle.
Also, I am willing to bet bore notching would show bigger gains when tested with a stock like 26* valve angle head, vs say a 24* angle or shallower head with a better canted angle.
