What plugs in your 383's
07-14-2009, 09:25 PM
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What plugs in your 383's What plugs are you running in your high compression 383's. Are you running coldest plug possible to stay away from detination ? 12.4 -1 cr ,33 degrees total timing. 160 thermostat and what plugs? THANKS JB
07-14-2009, 10:11 PM
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I don't mean to hi-jack but I am also curious what compression ratios yeild the best results on pump gas without having to pull any timing. I was considering running -5cc flat tops with a 64cc chamber which would be an 11-1 CR in a mainly street car that occasionally sees the track oh yeah and to be relavant would tr55s gapped to .045 work out in this combo?
07-15-2009, 04:30 AM
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I don't mean to hi-jack but I am also curious what compression ratios yeild the best results on pump gas without having to pull any timing. I was considering running -5cc flat tops with a 64cc chamber which would be an 11-1 CR in a mainly street car that occasionally sees the track oh yeah and to be relavant would tr55s gapped to .045 work out in this combo?
11.0:1 compression on an LT1 can be had simply from changing head gaskets (stock compression is around 10.6:1), so that would hardly be a step up on a 383 build.
I went from a .050" gap to a .035" gap on my 383 and picked up significant MPH.
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07-15-2009, 09:20 AM
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One thing I've always done is for every 50 or so hp added I go down a plug heat range n/a it's amazing the higher rpm cylender pressure generated by just a cam change.
07-15-2009, 03:04 PM
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Unfortunately it's not that simple. Static compression ratio is a fixed ratio and means nothing during engine operation. Do a search for dynamic compression ratio, and read read read. I have a DCR of around 9.1:1 (static is around 12.5:1).
11.0:1 compression on an LT1 can be had simply from changing head gaskets (stock compression is around 10.6:1), so that would hardly be a step up on a 383 build.
I went from a .050" gap to a .035" gap on my 383 and picked up significant MPH.
11.0:1 compression on an LT1 can be had simply from changing head gaskets (stock compression is around 10.6:1), so that would hardly be a step up on a 383 build.
I went from a .050" gap to a .035" gap on my 383 and picked up significant MPH.
07-15-2009, 04:03 PM
#14
Well I just did some research and it looks like because of the small duration of my cam my DCR doesn't really fall off as much. On 11:1 static I am getting a 8.75:1 dynamic compression ratio, everything I was reading seemed like it was geared to GEN 1 small blocks W/O the reverse cooling heads and they said 8.2 was optimal. Would a higher DCR also be possible due to the lower head temps of the LT1? What is optimal for a 383 LT1? I apologize to the op for the hi-jack but I seem to be getting some good info in thread...sorry
