454 4 bolt main or 2 bolt main

Do any of you guys know if the 1989 suburban 3/4 ton came wiht a two bolt main or 4 bolt main

Not an expert, but the chances of being a two bolt on a 3/4 ton, if that is the original engine is very small. 3/4 ton is a work horse, my 99 454 has a four bolt with the big heads from Chevy which is their stock motor that year. You need the engine number and call a rebuilder or call your chevy dealer parts department and they should have an exploded view on their computer. I f your dealer only shows one 454 for that year they can tell you if it is a 4 verses a 2. I run a 427 blue printed at 13:1 compression in my boat on a two bolt main. So do not think it cannot do a good job being just a 2 bolt. Also on a 4 bolt down by the oil filter their usually is a cast ironplug about the size of nickle, that is usually a give away it is a 4 bolt. When I am looking at an engine that maybe a core that is the first thing I look for to see if it is a 4 bolt since you cannot see through the oil pan. Sorry for the long responce.

I dont think is the original engine but im guessing its a 4 bolt because it has alot of power and it also have big heads.

Check just above the top of the oil filter on the engine block itself, may not be easy to do, use a mirror and if you see a screw out cast iron plug between the size of nickle and a quarter its a 4 bolt, but just because it is not there does not mean it is not necessarly a 4 bolt. But if it is there it is conclusive to be a 4 bolt main.