I had the same problem with my 99 2 door 4x4 Tahoe and couldn't figure it out. I had replaced the fuel pump when it went out months before. Turns out that aftermarket fuel pumps are not a good Idea. After going back to a genuine GM fuel pump, I had no more pump noise and start up is instant and purs like a kitten.
vortec is a brand name Chevy started using on 4.3l motors in 1986.
the vortec block and heads were introduced in late 1995 but actual vortec motor started coming in vehicles in 1996
if you are talking about the popular heads everyone wants. it started in 1996.
Probably about 240 or close. Move to a 96 and it's a lot more. The Vortec started in 96 with the 350 (5.7) and 454 (7.4). I understand the Vortec 5.7 had a little more power than the non-Vortec 7.4, and the Vortec 5.7 has 250 horsepower.
Apparently, there is none. They started using them in 1996.
Because a true 350 vortec I think relies on the vortec intake in order for the pressure to stay correct. I just remember i had my vortec box off of my truck one time I started it and It died just put the old vortec air intake back on and it should be fine. sounds like you have vacumn leaks around the intake manifold, this can be checked with a can of carb spray,
Vortec
My brother-in-law has interchanged the same flywheel before. He said it worked o.k.
Regardless of the block, you have to use Vortec heads to use a Vortec intake.
There are 4 different Vortec engines for that year. Stock horsepower at the crank are: The 4.3L (262ci) Vortec V6 has 190hp The 5.0L (305ci) Vortec V8 has 230hp The 5.7L (350ci) Vortec V8 has 255hp The 7.4L (454ci) Vortec V8 has 290hp
"Vortec did not come out until 96, yours was probably built late in the model year when they started changing the production line over. Unless you have fuel injection, the 95 uses a throttle body, similar to a csrb." Not entirely correct. Vortec came out in 1986 not 1996. See: http://en.wikipedia.org/wiki/GM_Vortec_engine Vortec is a trademarked name for a line of piston engines for General Motors trucks. The name first appeared in 1986 on a 4.3 L V6.http://en.wikipedia.org/wiki/GM_Vortec_engine
when did Chevy vortec come out