My old Accel has the square metal frame around the coil. The 8226 does not. Does this create an issue?

 

No issue at all.

Even the older MSD 8226 Coils looked like your Old Coil:

 

It is the same thing, just Plastic/Epoxy covered externally. That being said I have not had good luck with the MSD stuff other than the older 6A boxes before they went all fancy on them and the L31 Vortec Cap and Rotors. Coils and Modules have not had a good track record for me. I had the best luck with an old Accel Super Coil closely followed by the Davis Unified stuff I run now. I have had better luck with the Davis Unified coils and modules than I have with OEM GM replacements.

 

Thanks for the heads up. I seem to remember MSD being a pretty good product back in the day

 

MSD still makes good stuff. All of the brands are good.

But while there might be a technical standard for determining which ones are good, better and best, "best" is usually relative to each person's experiences with the various brands, so I look at voltage ratings, and Hypertech is the most powerful of the popular brands, by quite a bit over the next brand. I've been using it for about 17 years now, along with its cap and rotor, and it's been excellent. Huge improvement over stock.

These more-powerful-than-stock aftermarket coils allow you to run wider plug gaps too, which I do. And MSD Super Conductor wires, also among the absolute best, deliver that energy to the plugs. 3rdgen-tailored sets are available and fit perfectly. Look good too.

The minor increase in combustion = better responsiveness, power and efficiency. Far from earthshattering, but noticeable. The combination of small improvements adds up.

Hypertech = 53,000-55,000 volts
Accel Super Coil = 48,000
Davis Unified = 45,000
PerTronix = 45,000
MSD = 44,000
Street Fire (MSD) = 43,000
A Brand I can't remember = 42,000
Another Brand I can't remember = 38,000
Moroso = 32,000, which seems oddly low (might be a misprint)
Delco = in the 30,000s, IIRC

I also like Davis Unified. I read about DUI many years ago, and I really liked what I read. I'm looking forward to eventually pairing-up my Hypertech ignition coil with the DUI ignition module.

 

Taylor makes excellent plug wires as well. The Thunderbolt 8.8s are great, provided you do not put them into aged GM plastic clips which will then fail and allow the wire to fall on to the headers. Taylor will not sell a wire individually which is pretty dissapointing when you have 1 header burned wire and 7 good ones on a near $100 set of wires.

Coils are more than voltage though. What I really want to see is the mj rating as well as the resulting spark duration. Even though a coil may have less voltage it may have a higher mj rating. Atleast in theory the higher the mj delivery the longer duration the coil should be able to maintain the spark at a given secondary resistance value. So a coil with less voltage may have more total energy.

Most if not all single coils are limited in regards to charging dwell time at higher rpm. You can over saturate aka overcharge DIS/CNP setups and the magnetic field on some coils like the D585 GMs are known to collapse when the driver overheats and shuts down, giving an improperly timed spark. Have to be careful increasing the dwell on such systems even if they physically have the allowed time for increased dwell.

 

I don't have the time right now to get into this...
But like most manufactures today, some of their products are subpar and others are excellent.
MSD is like this.

In regard to Peak/ max. Coil Voltage... This is ONLY one aspect that influences ignition performance.
Coil Dwell Time, Stored Energy (in mj), the frequency that the ignition fires the same cylinder (multi-spark, as in MSD), and other aspects...
All are factors.