Sorry this isn’t an Olds swap question. I’m not active on any Chevy forums. I’m buying a running high miles Vortec 5.7 off sone kind of a ‘98 truck to put in my ‘80 K30 replacing LT9 SBC that’s in there now (spun bearing). Will be a budget carb swap. Will need to get the install done and truck running while I’m home on leave for holidays, so a bit of a time crunch. Want to line up parts now. Can anyone forward links to necessary parts lists?

Don’t intend to get into the long block for now (unless it is necessary/recommended).

Trans is factory TH400, don’t know converter. What flywheel do I need? Any fill tube/cooler line fitment challenges?

Assume old starter will fit on new motor? Might be getting the L31 starter with the new motor.

I’m not decided on carb, will either be a 750 cfm QJet or a 600 cfm Holley vac secondary square bore (I have both on hand). Electric choke both. Recommendations welcome. Any intake gasket concerns?

Will go with HEI, is that specific to Vortec, or will any early Gen SBC HEI fit? Also, believe I need some kind of soft gear?

Electric fuel pump that I can set to 6 psi (unless block happens to be machined). Currently only one fuel tank, but if two in future any pump considerations?

Was going to do long tubes (15/8 primary, D ports, I think?) if someone can recommend a cheap set that fits well.

Believe there is a plastic timing gear cover on the L31 that could be swapped?

Truck has hydroboost, so I was hoping I could swap pulleys/belts from old motor to replace serpentine set up? Is this straightforward?

Not sure of water pump/fan arrangement. Im getting the rad/fan from the L31, so could try and make that fit. Will go with easiest solution.

Not sure about alternator, hoping old brackets bolt up to new motor.

No AC at present.

Any other new parts I need?

Any other things to consider for the swap?

Finally, I got the fuel injection, harness, and ECM for possible future installation (also possible future 4L80E swap). Are there any other bits I should scavenge off the donor truck? Relays, junctions, fuse block, controllers, brackets, etc?

Thanks, and apologies again for non-olds questions - mark

 

You'll need a new intake. The old school SBC intake will not bolt onto the vortec heads.

All the accessories will interchange between the two motors. The water pump will swap between the two motors, just know that the serpentine pump on the vortec probably spins reverse of the v-belt pump.

Use the vortec flywheel as the old two piece seal flywheel won't fit the vortec.

no need to fuss with the plastic cover, leave it alone..

other than that it should be easy.

the hei will swap right in, there is nothing special required there.

 

Here is another forum that may be able to help as well. Good luck.
https://www.silveradosierra.com/

 

You need thew new style 1pc rear main flywheel & corresponding starter.... not sure what size flywheels are available.
Your truck likely had a 168 tooth flywheel & many are smaller 153 tooth with matching starter.

Get an aftermarket intake & carb.
You can reuse the early distributor.

Timing cover does not matter unless you want to run EFI.

Vortec heads flow well & will make good power.
If you swap the cam, be aware the Vortec heads have a tall valve guide & will limit max cam lift without guide modification\.

 

Thanks for the replies. So, definitely get the flex plate and starter.

Any thoughts on carb? I’ve read that 600 cfm is appropriate for the 5.7, but I’m pretty familiar with QJet and feel it could be easily tuned for a stock Vortec. Obviously, intake manifold will be determined by that choice.