370 w/ LS3/L92 top end questions
04-18-2010, 08:21 PM
#2
i really hate to buy the heads and intake just to find out that i have to buy different pistons than what i already plan on and it being more expensive. because right now, if i buy the L92 heads, LS3 intake, sell my current ported LS1 heads, and buy a 90mm tb ill be sitting at the $$$ spent if i keep my current heads and buy a Fast intake and TB for my current setup. actually i may come out ahead money and performance wise.
L92 heads 550 shipped
LS3 intake about 3XX ish
90mm tb around 300
thats about 1150 in parts
then i sell my ported heads for around 400
then im right at 750 which is less than im finding FAST 90/90 setups for right now and ill be ahead in performance as well....
L92 heads 550 shipped
LS3 intake about 3XX ish
90mm tb around 300
thats about 1150 in parts
then i sell my ported heads for around 400
then im right at 750 which is less than im finding FAST 90/90 setups for right now and ill be ahead in performance as well....
04-18-2010, 08:58 PM
#3
They will bolt on, I have an LQ9 with L92s.
The LS1 piston notch is for a 2.00" valve. An L92 valve relief is cut for a larger 2.160" valve. Although some piston companies just starte cutting L92 reliefs into everything.
You wont get 12:1 most likely. Im running true flat tops without any reliefs and Im right around 10.5:1
Watch PTV clearance VERY closely.
The LS1 piston notch is for a 2.00" valve. An L92 valve relief is cut for a larger 2.160" valve. Although some piston companies just starte cutting L92 reliefs into everything.
You wont get 12:1 most likely. Im running true flat tops without any reliefs and Im right around 10.5:1
Watch PTV clearance VERY closely.
04-18-2010, 09:28 PM
#6
they are Mahle pistons, i havent bought them yet, and i dont think Mahle makes a piston with an L92/LS3 notch yet....i do have a mill and fixture to flycut pistons, so that fixture will work to mill the notches out a little bit. if i can get Mahle pistons with the correct releif i would, i just hate to drop another 200+ dollars on diamond pistons just to have the bigger notch when i can mill this one out. unless Mahle makes the same piston with the right notches for the same price that im missing out on.
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04-19-2010, 06:59 PM
#15
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I have flat top mahle pistons,with valve reliefs in my .030 over 6.0 that were advertised as LS1 pistons. I have 823 cast L92 heads that have .025 thousands shaved and I am running GM MLS head gaskets for a 6.2. I used some clay and turned it over and I had no issues. I didn't measure, just wanted to make sure there was no contact. If you want I can dig through my receipts to get the mahle piston part number. My cam is a TSP 233/239 .595/.603
04-19-2010, 07:08 PM
#16
I have flat top mahle pistons,with valve reliefs in my .030 over 6.0 that were advertised as LS1 pistons. I have 823 cast L92 heads that have .025 thousands shaved and I am running GM MLS head gaskets for a 6.2. I used some clay and turned it over and I had no issues. I didn't measure, just wanted to make sure there was no contact. If you want I can dig through my receipts to get the mahle piston part number. My cam is a TSP 233/239 .595/.603
basically i need the CD of a piston for 6.125 rods. however, thoes pistons come with a .927 pin boss.
so i either need to get a custom piston with the .945 pin boss and 1.304 CD that puts me .005 in the hole which is better than .026 out of the hole...
unless i could get away with .026 out of the hole, then i could use a 4.030 piston for stock rods (if i can find one) or if Jon@HKE can dig one up, cause all im finding on Wiseco's website in a 4.030 bore is for a 6.125 rod....
04-19-2010, 07:20 PM
#17
You will also need to buy 8 offset intake rockers and LS3/L92 rocker stands. You can reuse the exhaust rockers. The LS3/L92 heads like a lot of timing. I started with 12:1 CR but could only run 24-25 degrees of timing. I dropped the CR to 11:3 and could run 29-30 degrees of timing and made more power. Don't trade off CR for timing.
There are MUCH better cams out there for these heads.
Just my $.02
There are MUCH better cams out there for these heads.
Just my $.02
04-19-2010, 07:43 PM
#18
You will also need to buy 8 offset intake rockers and LS3/L92 rocker stands. You can reuse the exhaust rockers. The LS3/L92 heads like a lot of timing. I started with 12:1 CR but could only run 24-25 degrees of timing. I dropped the CR to 11:3 and could run 29-30 degrees of timing and made more power. Don't trade off CR for timing.
There are MUCH better cams out there for these heads.
Just my $.02
There are MUCH better cams out there for these heads.
Just my $.02
the problem with my build is, my deck height on the block is kinda funky. the only pistons i can run with stock rods require me to bush the rods. however, the pistons also leave me .005 IN the hole. and im having a hard time finding a head gasket other than .051 thick. and im going to have to wait and get the short block assembled, and check PTV before i can decide how much i can mill the heads. but i honestly dont think ill be seeing anything over 10:1 compression...which saddens me becaues i know i dont need 12:1 after talking to a few people, but i think there is more power in a little more compression than 10:1.
04-19-2010, 08:39 PM
#20
You will also need to buy 8 offset intake rockers and LS3/L92 rocker stands. You can reuse the exhaust rockers. The LS3/L92 heads like a lot of timing. I started with 12:1 CR but could only run 24-25 degrees of timing. I dropped the CR to 11:3 and could run 29-30 degrees of timing and made more power. Don't trade off CR for timing.
There are MUCH better cams out there for these heads.
Just my $.02
There are MUCH better cams out there for these heads.
Just my $.02