Timing help

Would like some input. Running a blown alky chevy w/ whipple and bac-man heads 557 inches. Last year w/ 45 lbs of boost and 9:1 compression I ran 33 degress of timing, I have bumped compression this year to 10.8 and not sure where to start w/ timing. Thinking maybe 25 degrees btdc. Any thoughts on that?

 

MSD 44 requires less lead than Mallory super Mag-
Cylinder pres. is the key. MSD will fire under higher cyl pres conditions.

 

Ok let me throw a monkey wrench into the works. ignition is a MSD 10 electronic igntition.

 

I've had others tell me that, but the MSD-10 puts out 700 mj spark @ 14.4 volts and i run a 16 volt setup on mine. Hasn't failed to fire yet. We'll see with the increased compression.

 

just another point make sure you have enough fuel with that much of a compression change.

 

We run a 372 inch 5 second chevy at 10.8 but with a PSI at 50lbs The msd 10 is no good for us as they lose cylinders. we run 20s which are just fine. We run 30 deg lead, Keep an eye on the bearings and make sure it has enough fuel, A racepak or similar is one essential item.

 

Thanks for all the input guys. I'm taking her out tonite for some shakedowns. I've already increased the fuel and will be checking the egt's for dead cylinders.

 

I have been running a chevy with big chief heads and a msd mag 20 with 11.3 to 1 compression and i can tell you that 33 is to much for my set up . Toward the end of last year we bent push rods and wrist pins . Didn't run enough to figure it out last year but we will try 26 or 28 in a couple of weeks when we go out for the first time . Let us know what happens .

 

MOST FUEL + LEAST ADVANCE = GOOD!

 

Well i have good news. thanks again for the input, qualified #1 w/ a 4.73 @ 154 had the field covered by a full tenth, but went up in smoke first round, came back and twaeked a little and went a 4.64 @ 162 mph on 10.5's. Not bad considering the record is a 4.61. and that was with only a 1.22 60 ft. (normal 1.14-1.16) ran 28 degrees and wound up running the same fuel tune as last year, guess we were still pretty fat last year, but the lower compression let us slide by. the msd 10 still seems to be hitting on all 8. should be able to bust into the 4.50's this friday. we'll see.

 

I have been watching this with Great Interest.

I have a Blown BBC 509 with a 14/71 billet SSI

Run 30 lbs of boost and run a front drive dist with a programmable MSD 7 box with boost control.

I was told it could not be done. The car is 2470 lbs runs 106 60ft and 4.40 1/8 163 mph 6.70’s at 204+ it is power glide car.

This is the scoop I know.

The HVC II coil is a true 2amps to the plugs, MSD claims the 44 mag is only 1.75 amps the 20 is like 7/8 of an amp and the 4 mag is only like 450 JH.

This is the big deal right here. the Mags fire about 10 deg longer than an Elec Ing. This will let it burn more fuel in some cases. I run 30 deg of timing and have not tried to use the boost curve yet and to date had no problems.

I did learn you must run an electrode that is not a cut back type.

What plug and heat range have you guys been running.

I have been runing the Autolite 3932 I think it is way to cold.

Thanks

Todd Martin

 

MSD 7 & the blown vette
We did a lot of dyno pulls on our blower set up and early on tried the msd 7 ignition for several pulls using new and used boxes as we thought it could work. We found more power and torque with a mag.

 

Was it the new Digital Programmable 7 box?
Part # 7535? Any hints on a plug selection on a blown chevy. Thanks for the info.

 

No not the same MSD # It was a while ago that we did the dyno pulls and was so unsuccesfull that we stuck with the mags and now run a MSD 20 We have run a best of 5.83 in Malta at legal weight on a bad bad track at 90% humidity & 100F . On the plug part # :: In Europe the part numbers are different from US so can't help you there, if I give you our numbers it could screw you up and cost you a lot of $$$