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JaniH 04-17-2019 12:48 PM
Max overlap with these risers
 
https://cimg7.ibsrv.net/gimg/www.off...86d56f6d68.jpg

getrdunn 04-17-2019 05:24 PM
What is your build. If your searching cams I wouldn't get anothing under 112-114 lsa. I would think try and keep overlap btwn 8-14. Those risers will revert relatively easily. Especially if you idle a lot. I've been pretty fortunate over the years with the exception of my first marine build with a 109 lsa and stock cast manifolds. I never idled much with the exception of docking. Over 1,500 rpm out the channel however my first experience with reversion. It would still suck in some water periodically and get milky oil.

Does the water dump just past the 90 at the weld or closer to the end of the tip.

JaniH 11-10-2019 06:56 AM
Originally Posted by getrdunn (Post 4682656)
What is your build. If your searching cams I wouldn't get anothing under 112-114 lsa. I would think try and keep overlap btwn 8-14. Those risers will revert relatively easily. Especially if you idle a lot. I've been pretty fortunate over the years with the exception of my first marine build with a 109 lsa and stock cast manifolds. I never idled much with the exception of docking. Over 1,500 rpm out the channel however my first experience with reversion. It would still suck in some water periodically and get milky oil.

Does the water dump just past the 90 at the weld or closer to the end of the tip.
It dumps the water to the tip, going to extend the inner pipe almost to the transom. My build is 502 with ported peanut heads. Currently looking for flat tappet cams with tight 108lobe and 224 @.050. Duration, overlap 9° @.050 and 59° advertised. Lifters are rhoads original wich will cut the overlap to 48° advertised @ idle

hogie roll 11-10-2019 03:42 PM
Originally Posted by JaniH (Post 4714387)
It dumps the water to the tip, going to extend the inner pipe almost to the transom. My build is 502 with ported peanut heads. Currently looking for flat tappet cams with tight 108lobe and 224 @.050. Duration, overlap 9° @.050 and 59° advertised. Lifters are rhoads original wich will cut the overlap to 48° advertised @ idle
How fast do you want to spin it?

JaniH 11-11-2019 01:30 AM
Originally Posted by hogie roll (Post 4714440)

How fast do you want to spin it?
I think 5000rpm and it is all done, hopefully more. Have not measured intake runner volume after porting.

JaniH 11-12-2019 05:09 PM
Here is valve timing comparison of my lunati streetmaster 275/275 hyd flat vs Crane 731 hyd roller. I thought crane 731 would be good cam to compare, because it is almost always suggested here for mild bbc builds. If i have understood right the 731 should work without reversion even with silent choice. what you guys think?

Lunati. 275/275. 225/225. 104,ICL. 108 lobe.
Advertised. IVO=33.5 btdc. IVC=61.5 abdc. EVO=69.5 bbdc. EVC=25.5 atdc.
.050. IVO=8.5 btdc. IVC=36.5 abdc. EVO=44.5 bbdc. EVC=0.5 atdc.
Overlap. Advertised= 59. .050= 9.

Above Lunati cam with rhoads lifters. 15 degree reduced duration @idle.
Advertised. IVO=26 btdc. IVC=54 abdc. EVO=62 bbdc. EVC=18 atdc.
Overlap. Advertised= 44.


Crane 731. 286/296. 226/236. 107,ICL. 112 lobe.
Advertised. IVO=37 btdc. IVC=71 abdc. EVO=86 bbdc. EVC=32 atdc.
.050. IVO=6 btdc. IVC=40 abdc. EVO=55 bbdc. EVC=1 atdc.
Overlap. Advertised= 69. .050= 7.

GPM 11-12-2019 05:37 PM
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