100 cfm more with anular and downleg boosters can't beat AFR

Mattax said
Hughes2430, [270/276advert.] 223/230@50, 504"/.515" 108 LSA
+ rhoads vmax lifters added long before the headers.
I'll have to see what the cam card says for install. Although I was there and helped on a little bit, I don't have the install notes.
What has bit me twice now is not having important build details like this and actual cc info. I will never do an engine again without cc'ing the heads.

I actually did really no retuning to speak of. When I go the car back with the headers I pretty much just used it. I had an opportunity before work really cranked up to get some datalogs, but then the LM1 flaked out (turned out to be the 9V battery connection). So that was that. it ran pretty well. I did try one step hotter spark plugs late in the year.

Since Shrinker hurts your head so much here's a thread where Shrinker was asked why the AFR showed leaner when they swapped to 1 3/4 headers.

"It didn't 'lean out the carb' The exhaust has allowed more flow through on the overlap of the cam thus depositing Oxygen into the exhaust and causing the WB to read inaccurate. And that's why its lost power now, its not as hot in the cylinder at the start of the intake stroke so vaporization is less and combustion efficiency has dropped.
Yes it will need larger jets either mains or PVCR take your pick. The reason for that is not that the carby has changed AFR, that it not possible unless your exhaust pipes managed to grab a spanner while you weren't looking and changed the jets
The reason is whenever the energy input of the cylinder is not sufficient to gas the fuel you have to put more fuel into the cylinder so that the light fraction of fuel that gasses easier, makes up a combustible mixture. Its the same thing as when your engine is cold and you have to enrich-en it with a choke. Pulling the choke on enriches the mixture so that the light HC's obtain a combustible mixture ratio with a cold environment.
A simple statement that has to be learned is" its not about the AFR of the liquid its about the AFR of the Gas". That's Gas as in the state of the fuel, not the slang gas as in gasoline."

Lots more to chew on!:lol: