Greetings, GM EFI – This time, I’m requesting spark advance tuning advice from the assembled intelligensia. In my one-owner ’85 Camaro IROCZ28, I’ve a FT-cam’d, LM1 350ci block sporting a pair of ZZ4 aluminum heads to which an L98 intake manifold is bolted. The TPI intake and fuel injection are stock to the ’85. The ‘85 ECM is the stock ‘6870 and the mask is $1F_updated. While the engine builder installed a Hypertech Thermomaster 155332 PROM, there’s room for improvement IMO. In pouring over various threads in fora on spark advance – cast iron heads vs aluminum heads, I’ve compared the SA tables between the 85 Camaro (HLK bin) and the 85 Corvette (HLH bin), both sporting CI heads at the time (delta #s in red signify higher SA in the Corvette) – please see the 1st attachment.
In a similar fashion, I’ve compared the SA tables between the same FT-cam’d ’85 305 (HLK bin) and a rocker-cam’d ’88 350 (ABTT bin) Corvette – please see the 2nd attachment.
In both cases, the SA tables in the HLH and ABTT bins are higher than a CI head-equipped 305. While I get that Al heads can handle more SA over CI heads, it appears that AI heads over a rocker cam can handle even more SA that Al heads over an FT cam – does my understanding make sense?
Questions:
a) Since I’ve ZZ4 Al heads over an FT cam and I figure the Hypertech PROM’s SA table to be not much different than the stock HLK bin, would it be reasonable to import the HLH SA table as a 1st step to increase power in the mid-range?
b) Since I’ve a ‘6870 ECM and the $1F_updated mask does not make available knock counts in the datastream, would I be wasting my time on this exercise?
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