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-   -   Initial Timing on Blown Pump Gas SBC? (https://www.racingjunk.com/forums/showthread.php?t=17246)

alscoupe 05-12-2007 10:15 PM

Initial Timing on Blown Pump Gas SBC?
 
I guess I'm getting CRS or something.

Anybody remember the best place to start?

Solid 355 small block with 2.02/1.60 cast iron fuelie heads. 12% underdriven 6/71 with dual 650's. MSD 6AL series. Got a retard box on the way. Best initial time set? Degrees retard per pound?

Thanx.

billhendren 05-14-2007 06:34 AM

Whats your comp ratio and what fuel? Bill

margaritaman 05-14-2007 12:49 PM

Here is where I'm at just for comparison:
19 initial / 37 total. 1 degree per pound of boost retard.

383 / 8.5 static / aluminum heads 2.05/1.60 / 1:1 for 12 lbs on a 6-71 large bore / Demon 750s all on 111 octane. One step colder plugs.

My Demons love initial advance, more so than a comparable Holley.

Give the crew some more specifics and I'll bet you get some answers.

MM

billhendren 05-14-2007 02:10 PM


Originally Posted by margaritaman
Here is where I'm at just for comparison:
19 initial / 37 total. 1 degree per pound of boost retard.

383 / 8.5 static / aluminum heads 2.05/1.60 / 1:1 for 12 lbs on a 6-71 large bore / Demon 750s all on 111 octane. One step colder plugs.

My Demons love initial advance, more so than a comparable Holley.

Give the crew some more specifics and I'll bet you get some answers.

MM

You may want to lock your advance in the dist and set the timing at 36 deg,with 8.5-1 comp you shouldn't have any problems starting the engine and the 36 deg at idle and low rpm really cleans up the engine.keep your same 1 deg per lb.Bill

alscoupe 05-15-2007 04:30 AM

Thanx guys.

9:1 on 91oct.

What I figured, planned on bringing in 28degs by 2500rpm total, then backing down 1deg/lb up to 7-8lbs boost, puts it back on the bottom of the 28 to 34 total range at " on the f'n floor mode.

mcracecars 05-15-2007 07:25 AM

I have to agree with bill here, lock out the advance. These things go over 2500 rpm in an instant anyway so why fool with it. What I had on my old camaro... man I miss that thing.... put a switch to the ignition, get the motor spinning good, hit the switch, start everytime. Wheather or not it ran on all cylinders was another story. :shock:
Just my opinion, but I would go with about 32* total with the pump gas available these days.
If you go racing mix some race gas and sneek up on the timing, watch the plugs for signs of detonation.
Just me, but I dont put any faith in those retard boxes. Just something else to go wrong on race day. I would get rid of it myself, for the street, good pump gas, less timing, low boost. For racing, use race gas, more timing more boost.


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