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bt2
10-04-2006, 03:02 PM
ive got the msd 8934 digital e curve. i want 36* total. i have locked the dist. out and set it at 36* per the instructions an set the 25* curve i want but when i restart it will show 36* total but i try to let the motor idle down the timing go down to 11 or 12 but it wont run way to much retard. it will only run decent with 30* initial if i retard it any lower it wont run rightless than 20* and major exhaust temps. its a 350 60 over with rhs vortec heads comp cam xe274h weiand 8121 intake and 600 edelbrock carb i was gonna change the carb to my holley 750 double pumper once i get the timing where i want it. thanks by the way i have a 1959 corvette this motor is in and it has a 4 speed with 3.36 gears just trying to get it back together so i can get 1 last cruise in before snow flys.

68Formula
10-13-2006, 07:54 AM
That is a huge cam for that size engine! Even if you're compression ratio is decent you still might have a similar problem to what I do (did you get my pm?)

Start here:

Verify your balancer correctly indicated TDC by turning it by hand and seeing if the piston reaches the top when the mark lines up.
Check your cranking pressure. I'd guess you're 140 or less right now.
Also verify your manifold vacuum at idle (at desired initial timing or as close as you can get it). For a street car it's good to have at least 14".
If the balancer reads true and you're cranking compression is that low and low manifold vacuum, here's what I would do:


First redegree your cam to make sure it's not off. You might even give Comp a call and ask them for your combination if they recommend it to be (advanced?) degreed different than straight up. I forget at the moment which way it goes, but you can advance or retard a cam depending on where you want best torque and sounds like you need better cylinder fill at the low end. Comp ownes RHS so they should know what's best.

Second if you still don't get the improvement you want, try using curve M with about 22 degrees intial and curve 1 for vacuum, hooked to full manifold vacuum port.

Please let me know how it turns out.