Agree. My 475 stroker runs 23 deg advance at idle. Temp with A/C on at idle does creep up to 205 or so but goes right back down to 185 or so once cruising speed is achieved.
Agreed on both counts. I've had serious temp issue that turned out be the fuel mixture leaning out. As an extra margin of safety, I also installed a period-correct looking aluminum radiator. -MIG
Thanks guys - I’ll check the timing and AFR at idle but its an Holley super sniper so what it does after you set it initially is anyone’s guess. The cooling system is new aluminum. I was thinking it was the mufflers too because it runs just fine and nice and cool with the mufflers removed.
Doesn't the sniper have a screen (handheld controller) with all the readouts on the system? It doesn't tell you AFR, or at least target AFR? https://www.holley.com/blog/post/deep_dive_sniper_efi_5-inch_touchscreen_digital_dash/
It sure does - I’m just not at the shop and am not the guy who has been tuning it. They have plenty of experience with Holley FI but not on BBBs and it seems odd to everyone that it runs fine with the exhaust disconnected but gets hot with the full exhaust. Our first thought was too much backpressure causing the issue but now that everyone I have spoken to has pointed at initial timing advance and tuning, we’re looking into that first.
Open exhaust--exhaust reversion causes atmospheric air (oxygen) to flow into the O2 sensor. Sensor reports "lean". Computer richens mixture, headers don't glow. Closed exhaust--no atmospheric air to "fool" the O2 sensor into reporting a false-lean condition, computer does not enrich the mixture, headers glow. Is this plausible? I have no idea. I don't work with Holley systems, and I don't know where your O2 sensor is positioned in relation to the open-end of the headers. IF (big IF) this is anywhere near correct, your base tune is too lean.
https://youtube.com/shorts/nyeMTpfxy2k?si=EBP8Wmp1RYDtkVYB Idle video. Stock 455 minus a open air filter and deleted smog pump.
Anybody use the Gardner exhaust system? 2 1/2 in out of the headers and 2 1/4 in tail pipes. Has a good muscle car sound that doesn't drown out your radio's oldies & goldie's music. Lol
