Researching the benefits of the vortec heads on older SBC engines, I am curious if there is any difference in the vortec engines and the pre vortec ones? They are both iron blocks correct?

 

Yes both are iron block, iron head engines. No real major differences in the two.

Vortec block will not be drilled to use a mech. fuel pump.
Vortec block is setup for roller cam.
Vortec block has a plastic timing chain cover with a crank sensor in it and is missing 2 common cover bolt holes IIRC.

As I tell people, GM didn't give the trucks "much love". The trucks was way behind on the tech.

The vortec engine is just a modded gen 1 small block engine. Same basic design as all the other 1955 up gen 1 small blocks, with some improvements made.

You got to remember in the vortec years, the cars was running gen II engines, LT1 and LS1... Trucks was way behind.

Cars got roller cams in 1986, trucks didnt get the roller cam until the vortec engine in 1996.

The heads on the vortec engine is the very best thing about the engine. GM used the LT1 heads from the gen II engines to based the vortecs off of.

 

All the '87-up blocks came with the provisions for roller lifters, which aren't that helpful with Vortec heads because the intake port flow stalls above 0.475" valve lift. But the other advantage of the '87-ups is they were all EFI, so they generally don't need to be overbored. You don't need to take most of them to a machine shop. That makes them worth getting.

 

Kind of amazing that all those years, 1955 and up, the same thing worked successfully.

 

Truck blocks did not always have the spider holes drilled, nor the cam retainer plate holes drilled. I have also seen a few 88-92 truck blocks that didn't even have the lifter bores machined for the lifter retainers (dog bones)

 

That's why the sbc is the most used, most swapped engine. The year range is so wide and parts will swap back and forth, plus when they designed the sbc engine they had a great design that just plan out worked.

Sure over the years they made a bunch of little changes but overall it's the same engine as the 1st sbc made.

Added side motor mounts
added an oil filter
changed the rear main seal design 3 times
changed the valve cover mount pattern 3 times
Oil pan front seal thickness and oil pan front dip twice
Oil dipstick in 2 places
Intake bolt pattern changed 3 times
Added a PCV
mech flat tappet cam, hyd flat tappet cam, hyd roller cam
No acc. bolt holes in ends of heads, added bolt holes
4 diff spark plug designs.. The old big 13/16" wrenching plugs, the common 5/8" wrenching, longer reach plugs for the factory alum. heads, then the little longer reach plug for the vortec heads.

 

Vortec blocks have an external coolant bypass. If you are swapping to an 880 you will need to plumb that in, it is very easy. Some of the 880 blocks were machined for mec fuel pump also, non of the truck ones though.

 

I just swapped a vote in my 92 k1500 but pulleys and belt seem like they are off is that because shop didn't swap crank pulley?. Trying to deal with why I get nothing when I turn key. I had a shop install motor and they said they can't figure out what's up so I had to take it from there. We did a intake manifold to convert to carb and converted it from carb to TBI. Shop claims they had it running and set timing. I have yet to get it to run or turn over at all. It's not siezed. So question is what doesn't line up for pulleys etc? Or what should I swap this shop I used is useless.

 

If the engine doesn't turn over you have a starter / battery wiring /problem , nothing related to engine type or pulleys

 

Saw this post and to set the record straight. I have 2 different 880 blocks and a L30 305 block that were all drilled for fuel pump pushrods and came with factory block offs. They were also drilled and tapped for all the traditional timing cover bolts as well as have the bypass ports drilled for the older water pumps. One 350 came out of a 99 Tahoe, the 2nd a 97 Van and the 305 came out of a 96 van.