April GMHTP has a little message about L92 heads for 3.898 bore
02-21-2007, 04:33 PM
#1
April GMHTP has a little message about L92 heads for 3.898 bore page 10 at the bottom, GM is working on making small bore L92 heads for the LS1... project is not greenlighted yet but looks like something is in the works so we can use them on 5.7's and not have to switch to 6.0 blocks.. 
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02-22-2007, 11:19 AM
#10
Originally Posted by Stang's Bane
You better plan on turning some serious rpm to take atvantage of these heads. If you don't plan on turning at least 7K, you would be better off with a cathedral setup. IMO
Keith
02-22-2007, 11:28 AM
#12
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Not having seen the article yet, I wonder if GM shrunk the valve size or is making the leap to a 3 valve design to use this more efficient set up on the small truck motors. A redesign seems more likely though. It would make bigger noise in the media if it was the 3 valve, and smaller valves would have obvious draw backs.
Is there a picture with the snip-it in GMHTP?
Is there a picture with the snip-it in GMHTP?
02-22-2007, 12:10 PM
#15
Not totally true. They could do well in a F/I application.
Keith
Keith
why would you need higher RPM to do this? I thought you would just need a higher lift cam to take advantage of the flow
Didn't say it wouldn't work, just said that a well designed cathedral setup would work better on a 346 application.
Would they really be that good for a smaller displacement engine street car? I know they would make good peak numbers for cheap, but...
That is exactly my point.
02-22-2007, 04:58 PM
#17
is 4.002 and 3.898 really that big of a difference in bore size? doesnt seem all the hard for GM to make a small adjustment for this to work.. its not like going from LS7 heads(4.125) in which you need a minimum 4.100 bore to use the heads..
02-22-2007, 07:12 PM
#19
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they either had to make a smaller valve (intake especially) or they moved the valve? SO yeah that is quite a bit of extensive tooling/design changes. Theres a huge diff. in those two bores. I saw first hand an l92 on a 4.006 bore and the valves weren't close, but they didnt have a ton of extra room on the outside.
Originally Posted by GR33N GoblinM6
is 4.002 and 3.898 really that big of a difference in bore size? doesnt seem all the hard for GM to make a small adjustment for this to work.. its not like going from LS7 heads(4.125) in which you need a minimum 4.100 bore to use the heads..