oldeerslayer· Been there Done it
Block casting number 10243880's were used from 95-00 Could be from a 95 C/K or van with TBI. That would explain the smog era heads.Well you tell me the engine code is 10243880
That block was also used during the late 90's for almost all GM 5.7 crate motors. Including replacement engines for trucks dating back to 86. It was about the only 5.7 block made from 95-00. On the plus side it was also used for ZZ4 crate motors. But those had TPI aluminum or fast burn GMPP heads.
Take our collective word for it, that's not a Vortec L31. Between the 3 primary responders we probably have over 100 years of experience with S10's and first gen SBC engines. At first glance we all said it's not a Vortec. There reaches a point when you got to let an idea go. Whoever told you it was a Vortec obviously doesn't know Chevy V8's. Doesn't matter if the intake was added later. Everything else about the engine is all wrong. Particularly the heads, the parts that makes a Vortec better than earlier heads, which were designed for purely keeping EPA and CARB happy.
If you really want to build a good engine get some AFR or Dart heads. Way better than Vortecs. Which were the go to street head 25 years ago. Problem is they aren't any good above 5500. Today if it isn't making 600 HP at 6500-7000 it's a grocery getter. Built LS engines go 8000 no problem. Where the heads in the pic would be hard pressed to ever reach 5K or 300 HP.