- Joined
- Feb 28, 2025
- Posts
- 419
- Reaction score
- 590
- Location
- Rosemark TN
- First Name
- Jeff
- Truck Year
- 1985
- Truck Model
- C10 swb
- Engine Size
- 4.3L
Based on my Vortec 350 4wd 1t dually, the L31 is basically useless.
Needs:
Aluminum heads that can support a higher lift cam. It has torque, but no real top end power. If you have a flat tappet cam, good luck…
Desperately needs a 4bbl, on a real intake, with normal gaskets. The factory 2pc intake is fragile, and does not fit several of the aftermarket mpfi upgrades available. An industrial (2bbl) 350/SM465 in a C50/C60 will outpull a stock L31/NV4500.
The factory ignition system is terrible. Replacement sensors are delicate Chinesium junk. As are the alternators and replacement distributors. Buy a normal coil in cap hei distributor, good sparkplugs and good plug wires. Most aftermarket distributors will work with flat tappet or roller cams.
For the cost of upgrading the L31 into an actual work truck engine? I’d put in any medium duty tall deck, an RV 454, or if 2wd a Buick (only) 350-455 or big real Caddilac 425/472/500 and its matching Th400. Even an “ancient” GMC 302-6 or Chevy 292-6 is a better truck engine than an L31.
Needs:
Aluminum heads that can support a higher lift cam. It has torque, but no real top end power. If you have a flat tappet cam, good luck…
Desperately needs a 4bbl, on a real intake, with normal gaskets. The factory 2pc intake is fragile, and does not fit several of the aftermarket mpfi upgrades available. An industrial (2bbl) 350/SM465 in a C50/C60 will outpull a stock L31/NV4500.
The factory ignition system is terrible. Replacement sensors are delicate Chinesium junk. As are the alternators and replacement distributors. Buy a normal coil in cap hei distributor, good sparkplugs and good plug wires. Most aftermarket distributors will work with flat tappet or roller cams.
For the cost of upgrading the L31 into an actual work truck engine? I’d put in any medium duty tall deck, an RV 454, or if 2wd a Buick (only) 350-455 or big real Caddilac 425/472/500 and its matching Th400. Even an “ancient” GMC 302-6 or Chevy 292-6 is a better truck engine than an L31.
