I'd like to know exactly how these two engines compare.

Obviously the fuel delivery is different, really I just want to know how do the long blocks compare... ie block, crank, cam, heads, pistons, etc... Anyone have any detailed information on the specs of the Vortec 350 and the L98?

 

should I take the lack of replies to mean that no one knows how these two engines vary?

 

Welcome to the General Engine board, more questions than answers and the only section where a post will get buried in less than an hour

Don

 

Cylinder heads are different. Thats about it.
Vortec has different intake manifold bolt pattern, improved swirl into the chambers, kidney shaped combustion chambers, fast burn design, all sitting on a standard chevy short block.

Cheers

Richard

 

The Vortec 350's a 4bolt main block right? Are the cranks the same? What about the pistons? would the CR be the same if you bolted L98 heads on a vortec 350 block? and what are the vortec cam specs?

Anyone know anyplace where a person can find more info on the vortec 350?

 

Vortec 350 is not necessarily a 4 bolt main. 64cc combustion chambers gives 9.8:1 compression.
I will get cam specs tonight.
L98 heads will give you 9.0:1 compression, and will basically give you a L98 with a vortec truck cam.
There is nothing special about the vortec truck engines. They are 255 hp 350's designed for torque applications in a truck. They use a strandard L31 (vortec) single piece seal motor. The pistons are cast dished (13cc dish).
This is the same short block that is in my GTA.
With the restrictions involved in the TPI system, it produces approx 240 HP (crank) and 330 lbf(crank), at around 3800, and 3500 rpm respectively.

Cheers

Richard

 

Drew,

Check out the Vortec 350 buildup that Chevy High Performance did in the October 2001 issue on pages 72 through 76. It is exactly what you are talking about and pulled 422 hp on the dyno :hail:

 

along with many other differences, the internals are also lighter. i'd go into detail, but it has no importance.

 

The L31 heads dont have internal EGR passages as far as I know.

 

So, theoretically if I picked up a Vortec 350 from the junkyard, swapped in new bearings and rings, I'd have the same basic 350 that I'd have if I took a worn down L98 and swapped the heads to vortecs, etc... So then the $800 for a Vortec 350 makes a lot more sense then the $1500 the local junkyard would rape me over for a L98...

 

?

 

Yes, you should beable to use that. if you are looking for a little boost then you should get the Vortec TPI base and run it with the vortec heads. I think the timing chain is different too. My dads old vortec 350 from his 97 tahoe is what im going to be useing to build my 355.

 

Keep in mind that the truck Vortecs are not roller motors though.