LS engines without variable valve timing
looking into an LS build for a 70 Nova project, I'm told I should stay away from the newer engines with variable valve timing. I'm hoping to locate an LS 6 ltr. Can anyone help out with when these engines changed over to that technology. Also from the limited knowledge I've gained thus far I can find 6's in 2500 or bigger chevy and GM trucks and vans, the GTO, Pont G8, Camaro 03 and before. Any other models I should be looking for? I'm. hoping to buy a totaled salvage w/good drive train
Any input or advice welcome
Thanks