I just bought a very cheap 84 Chevy pick-up with a 1974 oval-port 454 in it from a friend. This is my first B-Block, so I got some questions! The 454 is stock as far as I can tell, but has a non-ECM controlled HEI, and a tiny 600cfm Edelbrock/AFB carb. I stuck a light on it and found 12 degrees at 700 rpm, and +52 degrees at 2700 rpm. 52 degrees advance would be silly on a SBC, is this acceptably on a BB:confused:? This engine has No-punch, and bogs for a few seconds when the secondaries are opened. Please help this BB newbe out!
The 52* is due to the vacume advance. Disconnect it and I'd bet total advance is in the 32* to 35* range. For what it's worth, I run 18* initial and 35* total on the boat engines with no vacume on 92 octance.
Thanks for the answer; I haven’t owned a non-ECM vehicle since I sold my Firebird back in 1989! So what’s the deal, do the mech/vac advances dial in real high advance during part throttle for emissions reasons? Back in the day, I had filed weights and light springs in the HEI on my 77 Firebird. But, I don’t remember ever achieving 52 degrees advance with, or w/o the vac diaphragm hooked up! I was thinking 10 degrees @ idle, and maybe 38 total?
Truthfully I’ve only poked around under this truck’s hood for about 10 minutes:bb; maybe the HEI is the 1984 OE, ECM-controlled unit? Since All of the sensors have been 86’ed, maybe this primitive ECM is freaking out and is dialing in ridicules amounts of advance? Well I guess I’m going to have to dig in that engine bay, and see what’s really going on in there:rolleyes:!
Corvette Store
Q 's about 454, non-vette, sorry.
