New LS build Cam Recommendation
09-20-2017, 09:13 AM
#21
Not trying to start a cathedral rectangle war, BUT......
That grind would be better suited for a 243 head off a LS6. The L92 is a great head and makes sense on a 6.0, but you will need two things done to really optimize:
1. The L92 is a very intake biased head. You tend to need more exhaust duration vs intake duration as compared to a cathedral head. In your case, that would mean likely keeping your exhaust in the high 230's and reducing intake to high 220's. A 227/239 - 113 would match up a lot better with the L92 heads and have less PTV concerns, if any.
2. Compression is your friend. That 70cc head would do you better at 64cc. That's a lot of milling, so you would have to worry about PTV. Or you could have them weld filled. Or you could swap to Pistons with better CR like flat topped or even domed. Which also effects PTV. Probably best to mill and then fly cut the Pistons.
Anyway, there's my $0.02
That grind would be better suited for a 243 head off a LS6. The L92 is a great head and makes sense on a 6.0, but you will need two things done to really optimize:
1. The L92 is a very intake biased head. You tend to need more exhaust duration vs intake duration as compared to a cathedral head. In your case, that would mean likely keeping your exhaust in the high 230's and reducing intake to high 220's. A 227/239 - 113 would match up a lot better with the L92 heads and have less PTV concerns, if any.
2. Compression is your friend. That 70cc head would do you better at 64cc. That's a lot of milling, so you would have to worry about PTV. Or you could have them weld filled. Or you could swap to Pistons with better CR like flat topped or even domed. Which also effects PTV. Probably best to mill and then fly cut the Pistons.
Anyway, there's my $0.02
I'd do a 232/248 108+3... and flycut the pistons. And then I'd mill the heads for 11.0:1 CR.
09-20-2017, 10:06 AM
#22
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And also mill and flycut. I really think that's the best path forward for cost and reliability. If you could get 11.5:1, i'd aim for that.