Well we finally have this truck running quite decently, probably the best I can do with what we have to work with. Some might find this interesting or of some value. I'll just recap briefly what we have:
1974 Datsun 620 pickup.
1991 5.0L HO.
Edelbrock Performer RPM intake manifold.
Quick Fuel Slayer 600 CFM carburetor.
MSD 8598 mechanical advance only distributor, 6AL control box, and Blaster2 coil.
Ford C6 automatic transmission with B&M Slapstick shifter.
Toyota limited slip differential, 4.10:1 gears.
If anyone is interested in more history and photos check out our thread in General Automotive Forums “FlexPlate and Starter Issues”.
I don't know what the original builder had in mind when he put together this package, but the combination of the C6, high ratio final drive and mechanical advance distributor, makes it pretty tough to make it a good street machine, other that itis different and it is cool. Anyway, my challenge was to get it running as good as I could with what they have without sinking a bunch more money into it. Here are the final tuning results:
Re-curved distributor for ~33 degrees total advance at ~3000 RPM, ~11 degrees initial (2 light blue springs, blue stop bushing)
No changes to factory carb jetting. Set secondary throttle stop just under 1/4 turn from closed
Idle mixture screws out ~1 turn
Idles at ~700 RPM, ~17" manifold vacuum ~13.2:1 AFR in neutral (engine seems happiest here)
Idles at ~550 RPM, ~15" manifold vacuum ~12.9:1 AFR in neutral (engine seems happiest here)
Cruise, level ground, ~80 KPH, ~3100RPM, ~20" manifold vacuum ~15.1:1 AFR
WOT, up hill, ~80 KPH, ~3100 RPM, ~5" manifold vacuum, ~13.1:1 AFR (hill wasn't long or steep enough to put a good load on it)
I hope this may of interest to someone.
1974 Datsun 620 pickup.
1991 5.0L HO.
Edelbrock Performer RPM intake manifold.
Quick Fuel Slayer 600 CFM carburetor.
MSD 8598 mechanical advance only distributor, 6AL control box, and Blaster2 coil.
Ford C6 automatic transmission with B&M Slapstick shifter.
Toyota limited slip differential, 4.10:1 gears.
If anyone is interested in more history and photos check out our thread in General Automotive Forums “FlexPlate and Starter Issues”.
I don't know what the original builder had in mind when he put together this package, but the combination of the C6, high ratio final drive and mechanical advance distributor, makes it pretty tough to make it a good street machine, other that itis different and it is cool. Anyway, my challenge was to get it running as good as I could with what they have without sinking a bunch more money into it. Here are the final tuning results:
Re-curved distributor for ~33 degrees total advance at ~3000 RPM, ~11 degrees initial (2 light blue springs, blue stop bushing)
No changes to factory carb jetting. Set secondary throttle stop just under 1/4 turn from closed
Idle mixture screws out ~1 turn
Idles at ~700 RPM, ~17" manifold vacuum ~13.2:1 AFR in neutral (engine seems happiest here)
Idles at ~550 RPM, ~15" manifold vacuum ~12.9:1 AFR in neutral (engine seems happiest here)
Cruise, level ground, ~80 KPH, ~3100RPM, ~20" manifold vacuum ~15.1:1 AFR
WOT, up hill, ~80 KPH, ~3100 RPM, ~5" manifold vacuum, ~13.1:1 AFR (hill wasn't long or steep enough to put a good load on it)
I hope this may of interest to someone.