Actally those are a good block for a cheap builder yours is a mix year with the 6 bolt cover and non roller, you can use a older style gen 4 roller cam in it just buy a new stock timing chain cover for a gen 5 (not 4 it wont fit pan rail) bolt it on with the 6 that you have 2 you will have to open up in the cover a bit and just drill and tap the other holes to 1/4-20 in the block, you dont have to use retro fit tall lifters you can just use gen 4 roller lifters You can now buy 1 pc stroker cranks for the same price but if you get a used stroker crank for 2pc seal just use a rear main seal adaptor about 40 bucks, I have taken the later gen 4 and 5 truck blocks to 4.500 no problem you can build a cheap 2xlong rod 540 or 572 no problem it is a 4 bolt block as well good builder on a budget have fun with it

o yea dont even think about putting gen 4 heads on it water water water, if you actually build it and need cheap heads I still have about 20 sets of gen 5 rectangle port gm heads