a friend bought a 1998 Z71 with a blown engine . since I had just installed a L31 Vortec in my Camaro he asked a few things about Vortec's . I looked at it and said sure enough it's a 350 Vortec . well yesterday got old engine pulled , scrapped crud away found engine was a 5.0 (305) . I said WTF , all outward appearance (heads) say Vortec . today I pulled a valve cover to look at numbers . cylinder head number 12552520 . put replacement eng. (from a newer J/Y truck) in today . newer 5.7 eng. has 906 heads as does my L31 GM crate . all I mean ALL , outward appearance on both engines are identical . oh yes , blown eng. (305) also has an 8" harmonic balancer . my question is WTF is the old engine . was there a 305 Vortec ???

 

Yes there was

 

Yeah, and it wasn't anywhere near as good as it's 350 Vortec big brother.

But just think how happy you're going to be when you step through on 45ci more displacement fed by the far-superior 350 Votec heads (that are radically better than the 305 Vortec heads)!

 

Yep made them in '96-98 IIRC, used only in trucks/vans/suvs. L30 was the RPO code.

It's a "vortec" 305. 9.1:1 compression, roller cam, "vortec" heads, but nothing like the L31 350 vortec heads. The 305s was more of a swirl port type head.

They also had 4.3L v6 vortec engines in that same time frame used in the blazers/jimmys

 

In defense of the 305 Vortec it was rated at 230 HP though..A lil stronger than the Lg4,Lo3,L69,and most LB9s.

 

Yeah, "it wasn't anywhere near as good as it's 350 Vortec big brother" is a bit misleading. It went from 170HP as an L03 to 220HP as an L30...a very nice jump. Just as the L05 went from 190/210 to 255. So as an upgrade, the Vortec treatment on the 305 was just as effective.

 

I can tell you right now having driven trucks and fullsize vans with the 305 vs 350 vortec, you really can't tell the difference between them. The 350 has a little more off-idle grunt but its not something you really feel seat of the pants in a 4,500-6,000 lbs vehicle.

The 305 heads on a 305 are just as good as the 350 heads on a 350 and probably better than the 350 heads would be on a 305.

 

well the results of my question surprised me . I can only assume that many people who think they have 350's in fact have 305's in trucks and vans . well your never too old to learn (I'm really old) . so an old phart like me learned a lot . thanks ................

 

You can tell on the trucks/vans/suburbans and what not pretty easily. On the 1996-2002 vortec years if it is factory a "M" in the 8th digit of the vin is a 305. A "R" in the 8th digit is a 350. The factory 305s came with a Y pipe and a single catalytic converter. The 350s came with dual cats and pipes back to the muffler. My 1997 G1500 came from the factory with the "R" 350 in it. You could get a light duty G2500 with the "M" 305 in it and you could get a heavy duty G3500 with a "W" 4.3 in it. Just depends on how the option sheet was checked.

 

I can tell you my friend bought a new vortec 305 single cab pickup the first yr they came out it was either 95 or 96. It ran off and left my single cab L05 pickup I had at the time

 

305 vortec was used till 2001. I just did one at work.

 

Yes, there were real 305 Vortec heads. I had always heard that they were only found in 1 or 2 years of Pick Up Trucks.


350 Vortecs, last 3 numbers of castings = 906 and/or 062 64cc Chambers


305 Vortecs = 058 58cc Chambers


At least that is what an old guy with "halfheimers" can remember!

 

They were built through 2002 for fullsize vans. The 4.8 didn't replace the 305 until 2003 in a Van. Also the 305 vortec is built to current day for marine use.