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| Cam suitability https://slantsix.org/forum/viewtopic.php?t=67593 |
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| Author: | 63slant [ Wed Jan 17, 2024 6:35 am ] |
| Post subject: | Cam suitability |
Hi all, I am looking for some advice from anyone who has a cam similar to the following specs. Just trying to rule out the cam as my source of tuning issues etc, so if anyone can tell me this combo should work I’ll keep chasing if not I will change the cam. Cam specs from engine builder 208@.050 110 lobe separation .450 valve lift. Engine is 9.0 compression with no headwork, HEI ignition, 350 holley, extractors and 2-1/4 single exhaust. 3 speed manual with 3.23 gears. 98 octane fuel in Australia. Thanks for reading. |
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| Author: | Greg Ondayko [ Wed Jan 17, 2024 6:40 am ] |
| Post subject: | Re: Cam suitability |
I would suggest some headwork to help that cam out. Larger valves at least 1.70" / 1.44" and some basic work on the runners and bowls. What is your installed intake lobe centerline? Greg |
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| Author: | 63slant [ Wed Jan 17, 2024 7:18 am ] |
| Post subject: | Re: Cam suitability |
Thanks, I am not sure but I can ask the engine builder, do you know what it should be? |
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| Author: | Dart270 [ Wed Jan 17, 2024 8:36 am ] |
| Post subject: | Re: Cam suitability |
Yes, the installed centerline can make all the difference. I would install that cam at 104 - 107 deg intake centerline. That is a pretty "tight" cam for 9.0:1 static compression ratio, so you will want to probably run mid or high octane fuel. It may ping some on low octane fuel. Having stock valves will not cause weird tuning issues, it will just not perform as well across the whole RPM range (as it would with bigger valves and some porting. Lou |
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| Author: | Rick Covalt [ Wed Jan 17, 2024 9:43 am ] |
| Post subject: | Re: Cam suitability |
What are the tuning issues? |
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| Author: | 63slant [ Wed Jan 17, 2024 1:35 pm ] |
| Post subject: | Re: Cam suitability |
Mainly pinging, I have put it down to my amateur skill level for the most part but that is wearing thin. Changed to a colder plug has seemed to help but still pings under load at the prescribed timing of 16 initial and 34 total at 3100 rpm. Going to keep retarding till it doesn’t ping anymore then play with the vacuum advance. |
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| Author: | slantzilla [ Wed Jan 17, 2024 2:11 pm ] |
| Post subject: | Re: Cam suitability |
Time to start filling/welding in the slots in the mechanical advance so you can keep a lot of initial and take out some total. |
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| Author: | Rick Covalt [ Wed Jan 17, 2024 2:22 pm ] |
| Post subject: | Re: Cam suitability |
16 is a lot of initial timing for a street car? Back it down to 10-12 and 28-30 mechanical and you should be real close. Then adjust you vacuum canister to fine tune. |
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| Author: | volaredon [ Wed Jan 17, 2024 3:59 pm ] |
| Post subject: | Re: Cam suitability |
Trying to make heads or tails out of cam specs makes my head spin |
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| Author: | Greg Ondayko [ Fri Jan 19, 2024 4:04 pm ] |
| Post subject: | Re: Cam suitability |
Yep, try setting initial timing at 12⁰ with the vacuum advance disconnected. |
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| Author: | Patrick [ Fri Jan 19, 2024 5:22 pm ] |
| Post subject: | Re: Cam suitability |
https://www.bulletcams.com/Masters/FClobes.htm https://www.bulletcams.com/Masters/FFlobes.htm anyone ever look at Bullet Cams to custom grind or regrind a factory cam? I was extremely happy with the reground hydraulic roller they did for me on a 318 magnum about 15 years ago. I was thinking of using them when I eventually start playing with my duster's slant....looking at something mild/streetable with a 0-5000 RPM range, so probably on the smaller side.... |
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