Main bearing torque on 98 Chevy 350 4 bolt main?? The main bearing caps should be torqued to 70 ft. lbs.
4 bolt main
No, different bolt pattern.
1500--2 bolt, 2500 4 bolt
no cause a 4 bolt main has 2 extra bolts on each main
The difference between a 2 bolt main and 4 bolt main is how many bolts hold the caps that hold on the crankshaft. (A 2 bolt main has 2 bolts to every cap and the 4 bolt main has 4 bolts to every cap) A 2 bolt main should be able to handle 500hp as long as you don't push it above 5500RPMs.
4 bolt their stronger better lasting
That would be a 4-bolt engine in that truck.
4
Yes an 89 350 will bolt up to original Vortec heads. However, Vortec heads have an 8 bolt inatke manifold that is different from the standard 89' intake. Its worth mentioning that the intake manifolds changed in 1986. Prior to 1986 all intake manifolds for a sbc had 12 bolts. These 12 bolts all secured the intake to the head at the same angle. In 1986, or primarily in 1987 the intakes 4 center bolts were changed to a steeper angle. With the introduction of the vortec head came a new 8 bolt intake eliminating the 4 center bolts. If you plan to use Vortec heads on any V8 be it a 305,327,350 or bigger, you will need a Vortec intake manifold as well. You can also buy an after market intake to run a carburetor on a set of Vortec heads in place of the TBI injection.
I can't answer your question but I can say that my 260 hp 350 Mercruiser has 2 bolt mains and a 4 bolt rear main. Go figure! So I take it from your question that you also have 2 bolt mains with a 4 bolt rear main.
To tell if your engine is a 2 bolt main or a 4 bolt main. Turn the engine upside down on an engine stand. Next, count the number of bolts on each main bearing cap. if there are two, then its a 2 bolt main. And if there are4, then its a 4 bolt main. This applies to the three center caps. The front and rear are always 2 bolt.