Mechrick
Active Member
- Joined
- Jan 10, 2020
- Messages
- 101
- Reaction score
- 65
- Points
- 28
- Location
- Las Vegas
- Vehicle Year
- 1984
- Make / Model
- Bronco II
- Transmission
- Manual
The Summit 600 cfm carb was equipped with 68 jets in the primaries and 73 jets in the secondaries. Whittled those down to 65 in the primaries and 67 in the secondaries. It's close, when throttling it just before the power valve kicks in, it shows 15.4:1-ish air fuel ratio, on a cool NV day. Some tweaking left to do. One concern is I'm at 2500 ft elevation. Death Valley is an hour down the road. Current jetting will probably be too lean for the Death Valley trails.
The ignition timing needs recurved for the Ford engine. The HEI has a standard Chevy curve, with about 20 degrees of mechanical advance. Vacuum advance adds 17 degrees to that. It needs more mechanical advance, about 26 degrees, and less vacuum advance, say around 13 degrees. I haven't checked the vacuum pot to see if it adjustable (yet). For now, I've dialed in 15 degrees initial until I find time to recurve it.
Front driveshaft went in easily. I found a 1310 to 1330 big cap conversion joint for the transfer case end, and a standard 1310 for the diff end. The shaft is installed backwards to help with clearance to the radius arm crossmember. I'll have to drop the crossmember with brackets at some point, something I want to do to allow 33" tires anyway.
The ignition timing needs recurved for the Ford engine. The HEI has a standard Chevy curve, with about 20 degrees of mechanical advance. Vacuum advance adds 17 degrees to that. It needs more mechanical advance, about 26 degrees, and less vacuum advance, say around 13 degrees. I haven't checked the vacuum pot to see if it adjustable (yet). For now, I've dialed in 15 degrees initial until I find time to recurve it.
Front driveshaft went in easily. I found a 1310 to 1330 big cap conversion joint for the transfer case end, and a standard 1310 for the diff end. The shaft is installed backwards to help with clearance to the radius arm crossmember. I'll have to drop the crossmember with brackets at some point, something I want to do to allow 33" tires anyway.