If your the guy that pays a mechanic to do the work and don't have the money to do it I agree walkaway, but if your like me and many others and DIY its no dramas "That want the OPs question BTW" . Lol working on the ls is easy as, currently doing lifters in mine and a cam, just collecting parts at the current time till i get a few days off to do the job as its my daily driver and only car i have to work around the down time. Things I would do in order of needed most and on a budget. I won't include oil but will say running 50 on a ls over 200K makes a world of difference and is keeping my lifters alive till i get them done.
1 Trunnion upgrade on your rockers in case there about to drop needle bearings through your engine, also the cheapest of making the top end strong.
2. Lifters and lifter trays, 4wd Power parts does a $660 pack off trays, GM lifters not the ls1 ones (LS7 lifters are a marketing name there all the same apart from ls1's), head gasket and bolts though you need a different head gasket i think as ya bores bigger) Heads will no doubt need milling and cleaning so $300ish if your got the dod crap do the conversion to get rid of it.
3. Cam oem specs or you can get away with a under 225 without a tune might run richer do your home work there. Grab a elgin $408.50 of amazon if you want something cheap that fair in quality or a crow or vcm $495. If the cam bearings are shot there not expensive though your going to have to pull engine and grab a ls cam bearing tool though there still cheap. Though I dont know anything about the ditching the dod.
4. Oil pickup where it connects to pump new gasket and twin bolt upgrade $19 ebay just make sure its nice and snug and don't pinch o-ring.
4. Cam retainer plate, the seals are crap its a $25 ebay part or if ya can't afford that a bead of gasket over the original.
5. Valve springs and seals comes down to your cam specs if going oem specs grab some ls6 springs, If not get something that matches your cam.
6. Oil dumb bell at the back of block, buy a billet one there not that expensive or at least replace the o-ring $1
7. Timming chain, there kinda bullet proof for daily driving but at 270k just for peace of mind $200
8. Oil pressure gauge in cab
After that your going to get to a point where your going to have to rebuild in the future, rings wear and bearings. Fun part is its going to be like new again, these are all my opinions and ruff estimates and im by no means an engine builder.
