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-   -   SBC Timing recomendations (http://www.hotrodders.com/forum/sbc-timing-recomendations-227754.html)

prostcelica 12-30-2012 05:38 PM

SBC Timing recomendations
 
Hey Guys. I just fired my motor today for the first time and was hoping to get some timing recomendations. Motor runs really well. Right know I have my initial set at about 12 degrees with the vacuum advance plugged. I'm all in at around 3000RPM at about 35 degrees. I think I could do with some more intial but I'm really not sure. See motor specs below and send some input my way. :)
If I have missed any info please let me know. Thanks in advance. (No pun inteded)

SBC 355
Comp 274 solid roller 234/244 at 50
Edelbrock estreet heads ported and upgraded valce train
10:1
Air gap intake
Holley 670 carb (probably a touch on the small side)
MSD street fire HEI with 6AL box
4 speed saginaw(for know)
Ford 9" posi 355's
2500# car

RWENUTS 12-30-2012 06:51 PM

10 degrees more initial with 10 taken out of the mechanical will really wake up that combo!

F-BIRD'88 12-30-2012 08:53 PM

22 to 26deg base initial ........... 34 to 36deg at max advance.
A limited 10 to 12deg mech advance curve, allows this. limit the adv travel.

+ a 12deg vac advance curve max . the rate has to be found by drive testing.
ported or manifold vac is up to you.

F-BIRD'88 12-30-2012 08:54 PM

establish how much base initial timing the motor likes.

techinspector1 12-30-2012 09:40 PM

Not saying that anyone is right or wrong with their ignition timing suggestions, but maybe some of you would like input from professionals who have done their dyno time. This first chart lists crank timing suggestions for less than 220 degrees camshaft duration @0.050" tappet lift.
Demon Fuel Systems
Click on the tab titled "Performance Cam Profile" for camshaft durations from 220 to 240 @0.050".....
Click on the tab titled "Radical Cam Profile" for durations up to and over 260 @0.050"......

cobalt327 12-30-2012 10:10 PM

Quote:

Originally Posted by prostcelica (Post 1628796)
Hey Guys. I just fired my motor today for the first time and was hoping to get some timing recomendations. Motor runs really well. Right know I have my initial set at about 12 degrees with the vacuum advance plugged. I'm all in at around 3000RPM at about 35 degrees. I think I could do with some more intial but I'm really not sure. See motor specs below and send some input my way. :)
If I have missed any info please let me know. Thanks in advance. (No pun inteded)

SBC 355
Comp 274 solid roller 234/244 at 50
Edelbrock estreet heads ported and upgraded valce train
10:1
Air gap intake
Holley 670 carb (probably a touch on the small side)
MSD street fire HEI with 6AL box
4 speed saginaw(for know)
Ford 9" posi 355's
2500# car

You definately need more initial. Limit the mechanical to keep the total from being too high.

More timing info here.

Good luck.

68NovaSS 12-31-2012 12:22 AM

You wouldn't believe how many threads there are in the searchable database on timing...give the search function a try.

vinniekq2 12-31-2012 12:28 AM

I agree that 670 may not be ideal.Does your MSD have a rev limiter?when that saginaw lets go you dont want engine splatter.If your engine idles well and the advance is quick,it might be close?

prostcelica 12-31-2012 09:41 AM

Quote:

Originally Posted by vinniekq2 (Post 1628950)
I agree that 670 may not be ideal.Does your MSD have a rev limiter?when that saginaw lets go you dont want engine splatter.If your engine idles well and the advance is quick,it might be close?

My budyy has a 750DP he is going to bring the first time we go to the track so I can make a pass or 2 with both carbs. Yes, my MSD box has a rev limiter. My buddy is also going to bring his extra Richomnd 4 speed the first time out and I told him ill bring my check book :).

vinniekq2 12-31-2012 10:01 AM

pro street,Im looking forward to see how your car performs.I know its been a while that we've been watching your posts.I wouldnt repair the car at the track,either do the upgrades before or fix later,why pay monet to work on their grass?
If you race it with the saginaw,try not to hammer the shifts and see what kind of MPH the car can achieve.Also,dont launch the car too hard,,,,
If you have traction problems,put a lower RPM chip in the MSD. I have a 6k chip in my MSD for street tire use. this helps lower the tire spin issue 2 ways

oh ya,,,have fun,,,

prostcelica 12-31-2012 06:23 PM

Thanks Vin. Ill be taking it to the track (port Mcneil) for the first time in june. I'm gona Buy the trans,clutch,scatter sheild,etc from my buddy that I described in an ealier post so I can run the car all out right out off the gate. I will let you guys know how it turns out MPH, ET, etc

Thank you guys for all your help through my first engine build. I have learned a ton from you guys.

Its much appreciated.


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