[thor1022]

i am building a 350 out of a 94 Chevy k1500. It came with the old spiral flow heads which suck. I have all the parts i need im just on the search for vortec heads now. i was able to get my hands on a set of 305 vortec heads off a 97 truck. they have a 1.85 intake and 1.5 exhaust valves. my question is will these heads flow better than the old spiral flow or should i keep searching around for a set of 350 vortec heads?

[cobalt327]

Originally Posted by thor1022

my question is will these heads flow better than the old spiral flow or should i keep searching around for a set of 350 Vortec heads?

Keep looking, IMO. The 305 (5L) Vortec heads are not just smaller valved 350 (5.7L) Vortec heads. The combustion chamber has a smaller volume, and I've heard the ports don't flow anywhere near as well as the 5.7L Vortec heads, and have a smaller port volume as well.

The 5L Vortecs may flow as good or even better than your current TBI heads, but the 5.7L Vortec's are where the payoff is. The 5.7L Vortec heads are readily available- look on craigs for either just the heads or an entire 5.7L Vortec engine.

Good luck.

[American Muscle]

ebay has those babies all day(350 vortec heads). Just be reader to be at your computer like your at barret jackson, bidding and winning is tough

[HOT ROD TWAN]

Will the 5.7 LT1 heads fit on a 80s block ??

[cobalt327]

Originally Posted by HOT ROD TWAN

Will the 5.7 LT1 heads fit on a 80s block ??

The Gen II SBC heads can be made to work- do a search here for several threads on this.

But the bottom line is the LT1 heads do nothing that the Vortec heads can't do as good or better- except for the Vortec's being made of cast iron instead of the 'Vette and F-body LT1 heads being made of aluminum.

[HOT ROD TWAN]

The heads I have are the vortex ones off a 94 chevy camaro . Will they work on a older block ???

[spinn]

Vortec heads gave me the fever. The only precription is cow bell.

305 are good but 906 are better.

Vortec heads on a 305 mini mouse teamed with a performer cam, springs, vortec performer intake, QJet, 3.73 gears with 28" tire , gave my C10 a kick in the pants. The stroke of the 305 is what keeps that boat anchor festive. My vortec heads are full size valve, umbrella sealed with no inner spring. Just the 3100V6/ LS6 beehive spring bids a little more lift clearance. THe 3.73 gear keeps the truck near its power band and always multiplies enough torque on tap. Never a saggy moment with the high velocity intake, carb, and head runners. Q jet hits like fuel injection. Trans mods included tuning governor for automatic 5,000 rpm 1-2 shifts with TCI kit. It takes 15 minutes.

Headers are about to be installed on her with Walker Quietflow muffs.

The vortec heads are the best bang for your deal. My Vortec heads spring and retainers were $250 +190 machine work + 80 for a intake. The results are incredible even with a stock cam. Upgrade is said to give 55 hp and 15# heads alone. My estimate is that is a fair assumtpion, depending what you start with. Biggest single acceleration gain from a mod is the vortec heads, then 2nd was the 2.73 gear to 3.73 swap. Headers and a dual side dump exhaust should be a winner too.

[DoubleVision]

Cobalt already answered your question. The LT1 heads will bolt on, but none of the coolant passages will line up. The LT1 is reverse flow cooled, meaning the heads are cooled first. Generation 1 sbcs`s cool the block first. This is why the passages don`t line up. To make them work on a older SBC you would have to weld them up then redrill them. Why do all this work when you can get a set of L31 Vortec heads bolt them on and go? The Vortec head was designed after the LT1 head, so it`s pretty much equal as far as performance goes. So to finalize your question No, they won`t "work" without a lot of work and fabrication skills.

[cobalt327]

Originally Posted by HOT ROD TWAN

The heads I have are the vortex ones off a 94 chevy camaro . Will they work on a older block ???

I shouldn't have eluded to the idea that they can be made to work, without also adding that the process to get them to work right on the 80's (Gen I) SBC block will cost far more than a set of L31 Vortec heads would cost.

Listen to what DV has said- and you'll be fine.

[Hippie]

Originally Posted by cobalt327

Keep looking, IMO. The 305 (5L) Vortec heads are not just smaller valved 350 (5.7L) Vortec heads. The combustion chamber has a smaller volume, and I've heard the ports don't flow anywhere near as well as the 5.7L Vortec heads, and have a smaller port volume as well.

The 5L Vortecs may flow as good or even better than your current TBI heads, but the 5.7L Vortec's are where the payoff is. The 5.7L Vortec heads are readily available- look on craigs for either just the heads or an entire 5.7L Vortec engine.

Good luck.

I realize this is an old response but thought I'd add a couple comments in case someone doing a search for info on L30 heads comes across it. It's true the L30 305 Vortec heads do not flow as well as the L31 Vortecs and they do not have the heart shaped chambers. However, they do flow considerably better than most earlier production line factory iron SBC heads, especially the TBI swirl port heads. If you can get a set cheap enough they are worth taking a look at for a mild build. Problem is most sellers think they're made of gold and ask the same price as L31 heads. I got mine off a core I bought to get the roller cam hardware. I was going to gut them for parts for a set of '416 HO heads until I started looking at the runners. I did some research and found flow numbers posted by someone I know from some of the Chevy forums. I put the '416 heads under the bench and hauled the L30's off to the machine shop instead. I had the guides machined down for more lift when I had them rebuilt. The machine shop has done hundreds of Vortecs and said many they have done actually experience interference at .440 to .450" valve lift.

I'm presently collecting pieces to build a 355 for my '88 C1500. I have the fresh set of '520 L30 Vortec heads, NOS TRW L-2441 21.7cc D-cup pistons, a stock Vortec roller cam and the '395 Ramjet roller cam (still undecided on which one) and a GMPP Vortec TBI intake manifold. Compression will be about 9.2 to 1 depending on final deck height. I'm also switching out my 2.73 gears for 3.23's and a posi. I still need to pickup some upgrade pieces for my fuel and ignition systems and headers with the Vortec EGR fitting. I'm going to upgrade my ECM with an add on package that will allow me to reprogram without burning chips.

Things are slow at work right now so I'm holding off until I know if I'll have a job later this year or not.............

[DoubleVision]

Sounds good Hip. Tell me more about the add on program, I`m curious about it, that sounds like something I may look into for my 4.3 TBI.

[the nitro man]

there is a post over on a z/28 forum about these heads. they said they flowed almost as good as the 062/906 heads. the flow numbers was there too. they are a much better head than the 601/416/434 heads.