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Discussion Starter · #1 · (Edited)
Need some advice on this one guys. I just bought a new 6al ignition with mechanical advance distributor. Here is what I have

355, 12:1, roller rockers 1.5 intake 1.6 exhaust, RPM airgap intake with proform 750 center section and 650 metering blocks, 3800 stall with powerglide 1.76 1st gear, transbrake and 4:10 in the rear, Dougs headers with 2.5 V Force Mufflers

Cam is a solid lifter:
Operating Range: 4000-7500 RPM
Duration Advertised: 290° Intake / 298° Exhaust
Duration @ .050'' Lift: 252° Intake / 260° Exhaust
Valve Lift w/1.5 Rockers: .536'' Intake / .554'' Exhaust
Lobe Separation Angle: 112°

My question is which curve would you start out with given my current engine setup? I figured I'd start out with 12-14 degrees initial and have a total of 37.
At what RPM would I want it all in by? Is it true if I have it all in by 2500 or so it will help my ET? I know thats probably not the best for street driving but I can always change the springs and bushing when I'm not at the track.
 

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I run mine locked out with 36° all the time. I never worry if I have the right curve!
BTW, Have you tried the rockers switched the other way? 1.6 on intakes/1.5 on exhaust.
 

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Discussion Starter · #3 ·
I run mine locked out with 36° all the time. I never worry if I have the right curve!
BTW, Have you tried the rockers switched the other way? 1.6 on intakes/1.5 on exhaust.
I guess that's one option. I wonder how hard mine would start when its hot and timing locked out at 37 degrees? I do have a high torque starter which should be able to do it. Or I could buy a timing retard box.
No I haven't tried the rockers the other way, what would I benefit from it?
 

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ignition switch

run a separate switch to turn the ignition on after the engine is cranking over, works like a champ. I tried it locked out once and just had hard starting issues but not starter cranking issues with an HEI distributor, then switched back to old set up
 

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It typically makes a bit more power. It's a lot harder to get in there than get it out.:yes:

As for the advance curve, try the Black bushing and one of the lightest springs and one of the next stronger springs. The reason for not using both of the lightest springs is because they are too weak and tend to let the advance mechanism "Bounce around" a bit.

The black bushing will allow you to set it up with 19* of initial and 37* total (18* of mechanical advance) and the spring combination should have it "All in" around 3000 RPM. With a 3000+ converter, "All in" @ 2500 or 3000 won't matter.:no: But the timing bouncing around with a lean tune and nitrous WILL!!!:devil:
 

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I wonder how hard mine would start when its hot and timing locked out at 37 degrees?
I've run the same set-up in a 14.5-1 comp. 414", a stock 350", a slightly modified 350", a 10-1 comp. 383", a 13.9-1 comp 391", a 12-1 comp 410".........With the GM permanent magnet style starter that I'm using, it starts just fine--with my old stock starter I would spin it before turning on the ignition. Even in Phoenix at 117° it wasn't a big deal.
 
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