Finally got around to doing the thing.

[L31MaxExpress]

I like to set my idle timing for highest vacuum/lowest IAC. In theory. in reality I don't have electronic timing control
YET! By sheer coincidence, my 455 in my firebird likes 34 degrees as well!

I went about 6° less timing than it idles at maximum vacuum at. That allows the PCM to be able to increase the timing to help raise idle speed. Stock the PCM can vary the timing around 10° up and down from the base point, which is usually about 23° on a L31. I limited the PCM to 5° up and down for idle control with this setup.

 

[Frank Enstein]

That's just cool!

 

[Scottm]

It sounds great! What is the source of the 4" maf?

 

[L31MaxExpress]

It sounds great! What is the source of the 4" maf?

Spectre 4" housing, Hitachi GM cartridge MAF for a LS7 and matching connector. MAF flow straightning screen from SaxonPC.

Just found a guy that went into details with links while trying to search up the part numbers I used.

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[L31MaxExpress]

This is what it sounded like with open headers and the startup tune.

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What it sounds like from the back of the van after bolting up the exhaust but with the cutouts open.

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Still need a little more work on the throttle follower to make it return to idle a little more quickly but it idles very stable after a throttle stab and no tendency to stall or bounce off the stall saver. I love the decel crackle pop even.

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[Scottm]

Wow cool How do you program the bigger maf into the tune?

 

[L31MaxExpress]

Wow cool How do you program the bigger maf into the tune?

Played with the IAT calibration until it read the right air temps prior to starting the engine. Then adjusted the MAF table until I nailed the fueling.

 

[L31MaxExpress]

Been playing around with the tuning and finally decided it was safe to crank up the RPM. Engine has seen 6,500 rpm with the carb. Have the fuel kill set at 6,200 now in the tune. Absolutely rips up the rpm range.

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[Ol Hubb]

This is so much cooler than an ls swap

 

[L31MaxExpress]

This is so much cooler than an ls swap

Actually have a 6.0L and had a LSA to go on it. Decided to keep the Gen1 because the LSA blown LS would have been impossible to do anything with. The Gen1 engine Express vans have the smallest engine compartment out of the 3 designs. The LS vans are wider around the engine. I actually also bought an 8.1, headers and a cam to swap into it first back in 2015 and had everything to swap it in, but chickend out on cutting the firewall and the floor.