Converting Big Block to Coil per Plug

[ohcbird]

First off,what EFI are you going to use? most of them can be made to drive the CNP setup, or are already able to do so. If you don't mind the extra wiring & work to mount/hide them, they'll be worth the trouble. Look at DSE's customer site to see how they hid the wires on Billy Chandler's 55, you could do something like this:

http://www.detroitspeed.com/projectp...andler-sub.htm

Here's a few more good reasons to run them:

1. Since you'll have 8 coils, the average heat produced by each coil can be shed quicker than one coil firing 8 cylinders. This adds longevity to the life of the coil.
2. The spark will be more controllable & predictable across the whole range.
3. The odds of all 8 failing & leaving you starnded is much lower than one coil dying & you being stuck somewhere.
4. Most of the EFIs can pickup the coil feedback signal & detect a bad coil.
5. No messing around at the back of the engine for timing (one the sync is set). Sit in your seat & adjust till the cows come home.

As J2 said, don't waste your time on the MSDs. The factory truck coils are the way to go.

[gmorris]

Originally Posted by ohcbird

First off,what EFI are you going to use? most of them can be made to drive the CNP setup, or are already able to do so.

As I said in the first post, I'm planning on trying the new Holley HP EFI setup which has the ability to drive seperate coils itself.

I keep waffling between just staying with the current MSD/single coil for now and then maybe doing DIS later or just going for it all now. Either way I will likely install the crank wheel this winter since I'm going to have the front accessories off to swap cams anyway. Getting rid of the distributor is appealing but I'm not convinced there is enough benefit to offset the cost/hassle since I get the ease of timing adjustment either way. Not having to mess with my distributor any more will be great.

Good to know the MSD coils aren't worth it. I was leaning toward the truck coils anyway.

[64duece]

I did the exact swap your referring about. MSD/FAST Dual Sync/HVC Coil over to the Holley DIS setup using 60-2 trigger, Holley wastespark coils and the 1x Cam Sync from EFI Connection.

The benefits I've seen so far: reduced spark scatter, slightly cleaner looking plugs and the obvious appearance advantage as all my components are mounted out of sight.

Having a 55 Chevy, I was able to mount my coils on the "splash pan" behind the front tire and route the plug wires accordingly. With the wastespark, it does make the plug wire routing abit cumbersome. There are a few good pics on Mike's site for coil mounting ideas.

http://www.eficonnection.com/24x/24x_CoilMount.htm

If you decide to use a distributor, I would recommend using it for the cam sync and running the 60-2 crank trigger to gain the spark accuracy advantage. You can always add coils at another time with this configuration.

[gmorris]

Originally Posted by 64duece

If you decide to use a distributor, I would recommend using it for the cam sync and running the 60-2 crank trigger to gain the spark accuracy advantage. You can always add coils at another time with this configuration.

That's what I was thinking...especially since I'll have all the accessories off this winter anyway mounting the wheel is easy. Is the crank trigger setup expected to be released around the same time as the efi systems? Do you mean use a specific cam sync distributor (like an accel dual sync) or can you just use the msd pickup as a cam sync? Did you gain any idle/low rpm improvement going to the DIS?

[64duece]

Originally Posted by gmorris

That's what I was thinking...especially since I'll have all the accessories off this winter anyway mounting the wheel is easy. Is the crank trigger setup expected to be released around the same time as the efi systems? Do you mean use a specific cam sync distributor (like an accel dual sync) or can you just use the msd pickup as a cam sync? Did you gain any idle/low rpm improvement going to the DIS?

That release of the DIS componenets shouldn't be far out from the initial release of the EFI. I prefer a hall effect pickup vs a modified mag pickup due to the possibility of injecting noise into the circuit and losing sync. I've done this with FAST XFI without issue but, haven't tested it with the Holley EFI. I can let you know on this.

My car is cammed mild so, it already idled very well with 15" of vac. I'm pretty picky when it comes to idle so, I'd say a small improvement has been made in respect to idle hysterisis.

[gmorris]

I've read that there can be issues when removing 7 teeth from the reluctor of a standard distributor to use as a cam sync due to algnment and phasing issues. I suppose that should be effectively adjustable by just turning the distributor as if adjusting timing?

[jmac]

Hey KennyD, are you sure its Granatelli that makes those valve covers? I've been searching their site and cant find them. You have a link or some pics? Maybe its another manufacturer?

[Efi69Cam]

Originally Posted by gmorris

I've read that there can be issues when removing 7 teeth from the reluctor of a standard distributor to use as a cam sync due to algnment and phasing issues. I suppose that should be effectively adjustable by just turning the distributor as if adjusting timing?

The distributor from a vortec 350 makes a good cam sensor. It has the correct 180' reluctor.