Rich Idle $12p 304

[Wade]

28 is nothing unusual, a larger cam than stock can be anywhere from 24-32 deg from what I have seen and experienced, especially with stock or lower comp than the cam actually wants, results in even higher timing.

If it wants 28, give it 28. Brindo has a point, the timing could be offset due to the dizzy or something. Not uncommon on any engine that runs a dizzy for EFI, but still, 28 is not crazy by any means.

Pretty sure my brothers 304 was getting best vacuum at idle with 28 degrees and stock cam.

[seanlivingstone]

Have you set kinjflow for the 42lb injectors and are they genuine its very hard to find genuine ones

This could definitely be the issue, they look genuine but can’t confirm it unfortunately, I am pretty sure kinjflow and dead times are all set correctly! Thanks for all the help guys, this one’s killing me haha

[brindo]

There’s also the min BPW, particularly if its too rich at idle. But this is part of the dead time settings.

28 degrees may well be where best vacuum is, but if it is stalling at anything lower there’s something else at play. Getting the AFR right at idle may well solve this.
Those injectors are also quite big for what it is. Changing the whole map to single fire would be a simple no cost option to try and see if you get an improvement. I had 42lb Bosch Motorsport green tops in that 355 with a slightly larger cam, and found a big improvement moving to single fire. Duty cycle was only around 30% so moved to a smaller injector. You have the newer 42lb green tops, but as Delco says could be fakes.

[vlad01]

28 is nothing unusual, a larger cam than stock can be anywhere from 24-32 deg from what I have seen and experienced, especially with stock or lower comp than the cam actually wants, results in even higher timing.

If it wants 28, give it 28. Brindo has a point, the timing could be offset due to the dizzy or something. Not uncommon on any engine that runs a dizzy for EFI, but still, 28 is not crazy by any means.

Pretty sure my brothers 304 was getting best vacuum at idle with 28 degrees and stock cam.

Not a 304, but a crow stg 3 cam in an otherwise stock VR 6 engine. Factory is around 20 deg, which is the same at the v8 iirc, and although the crow stg 3 cam is pretty mild, less than the OPs one, it still wanted this. Similar LSA too.

You can actually compare a 304 and 3800 roughly enough with stuff like this because the per cylinder volume and comp is basically the same and that is all that pretty much matters when it comes to the base specs and cam of any engine.

Screenshot from 2026-09-09 09-05-12.png

[VK_3800]

I had to enable single fire to get reliable low rpm/idle fuel delivery with the 60lb Dekas, could be borderline? Your injector settings will need to be spot on to transition between the two nicely

[seanlivingstone]

I had to enable single fire to get reliable low rpm/idle fuel delivery with the 60lb Dekas, could be borderline? Your injector settings will need to be spot on to transition between the two nicely

Thanks again all! I’ll give this a shot next time I’m next to the car, yeah the injectors are too big for what it is, if it doesn’t work going to single fire I might convince him to put a set of ls1 injectors in it and go from there!

[delcowizzid]

Yeah set it to single fire at low pulsewidths and let it switch back once rpm is up and pulsewidth gets wider.also done set idle spark at the highest you can ti get vacuum or idle spark control won't be able to add timing to help with idle control.you want it to be able to add upto 10 degrees