question on new engine

[zappej]

So i found a good deal on a 99 5.7L on craigslist comes with heads and intake. So my question is what would be involved into retrofitting it back into a carb? and would i need to move the mounts on my 73? I figured since the vortec heads are a good upgrade for us, a fresher motor couldn't be bad either right? i tried doing a few quick searches with no luck
thanks for your time
Justin Zappe

[VileZambonie]

I'm building one now. It's a roller cam so if you upgrade the cam, you'll need a roller. You'll need a vortec intake manifold. If your using the serpentine setup you'll need the 99 waterpump. Everything else is pretty cut and dry

[eventhorizon66]

If you have a V8 now, the L31 will bolt right in.  It is still a Gen 1 SBC.  All you should need to convert to carb is an intake.

Some considerations are: type of carb (Q-jet or square bore), type of choke (you can only run electric or manual with the vortec heads), throttle cable bracket (will need to be modified if it is the style that uses the rear two most driver side intake bolts), AC bracket (will require modification if it is the style that uses the front two driver side intake bolts), water pump (if the new engine comes with a pump and you still have v-belts you need to buy a new standard rotation pump and run a bypass hose to the intake, like on a BBC).

Also, according to this site: GM replacement L31 engines do not have a mechanical fuel pump provision.  Not sure if all L31's were like this, but if so it's something to consider as it would mean a switch to electric.

[Blue 82]

Don't forget to get the Mellonized distributor gear if you are gonna the factory roller cam
I had to get one for my TBI rebuild with an L98 cam
Talk about a PITA tracking down one with a .431" ID
The standard HEI is larger
I have both part numbers if you need them.