goodwrench 260 or L31 vortec

[eventhorizon66]

There is one more thing that I feel is worth mentioning.  The L31 engine has about 9.5:1 static compression and a when combined with a very small cam means fairly high dynamic compression.  And while the vortec heads promote faster combustion, require less ignition advance, and are more octane friendly, that compression may still be too much for 87 octane in your application.  I cannot say for sure.  These engines only called for 87 octane in their original applications, but they also had the advantage of knock sensors and electronically controlled ignition timing to keep them safe under high load conditions.  If potentially running 89 or higher octane is an issue for you, you may wish to hear from someone who has run this particular engine on 87 successfully.

[74chev4x4]

Thanks guys really good info, I was wondering about the compression and octane gas, anyone run this motor on 87 with any problems?

[74chev4x4]

anyone have suggestions of what intake would be best for this L31 motor, matching the intake with where the motor makes its best torque powerband?  I'm looking but its a little confusing.

[eventhorizon66]

Low-rise dual-plane.

USA made: Summit Racing 226018 (summitracing.com $130), Edelbrock 2116 (flatlanderracing.com $155), Weiand 8121 (summit $166), Edelbrock 2716 (summit $185)

Chinese made: Professional Products 52007 (summit $140)

*I am fairly certain the summit intake is a rebranded Weiand intake.  Compare them and I bet that aside from the logos, you can't tell the difference.  I can't.  Call summit and confirm.  It looks like the sweetest deal.

**The Summit, Weiand, and more expensive Edelbrock manifolds are square bore to work with Holley or Edelbrock carbs only.  The other two are spreadbore, which work with Q-jets and squarebores.