To start off, I have been given the Scoggin-Dickey TPI base plate from my father for my 87 IROC Z28 305 TPI 5 Speed. I have had this car since I was 16 & the car just turned 56k original miles 2 weeks ago and has been put in my garage for winter.

I have other projects like my 70 Camaro & painting my 95 Z28 (goes 12.0 in 1/4) going on but am interested in putting some vortec heads on if the difference is really there & if people think its worth the effort. I know it is a 15 hour job at least.

I have done a lot of searching and asking around. Some folks have said its worth it while others tell me just to leave the car stock and original. It does have a 3" flowmaster cat back on it (whoopee).

I have been meaning to put a set of 1.6 roller rockers on for the hell of it for a bit more lift and relieve some valve train friction.

I have been offered a set of complete 906 heads for $200. Summit Racing heads are $317 complete.

Not planning on selling the car anytime soon but i might down the road. Paid $5000 for it when i was 16.

So is the 15 hours of work worthwhile for it? Are the vortec heads worth putting on, since I am not doing tons of other mods?

Curious to know what you all have to say.

 

http://www.popularhotrodding.com/eng...s/viewall.html

Take a look at this. With good heads and a good cam, you can reach up to 300hp

 

Would have to mill the heads to get your compression back
IIRC 305 heads are 58cc ; Vortec heads are 64cc

Read
http://www.carcraft.com/techarticles...d/viewall.html

 

Thanks for the replys and good reading. Seems all these folks did a cam swap though with the vortec heads. I was just thinking of putting the vortec heads on and leaving the "peanut cam". If the gain is only 30-40 horsepower then why bother spending the 15 hours worth of work.

 

Well if you're that far into tearing apart your block a cam swap is really no big deal from there. Take the timing cover off, lower the oil pan a bit and you are ready. Might as well make the most of it, plus you might be pleased with the results.

 

I wouldn't even think about doing all the work to change heads and not consider the cam. Throwing in an LT1 cam will really wake up that 305 ( did for my L69!). Other choices are available, but you don't want to go too radical on a 305 with the computer. Also stay below .470 lift with the stock vortecs.

 

Not worth it if leaving stock cam. Peanut cam doesnt even hit full potential in stock heads and wouldnt do any different in vortecs.

Swap cam heads intake and runners and tune it. It will wake up alot

 

Someone correct me if I'm wrong but 906 vortec heads won't fit a 305. The intake valve is to large.

 

Vortec cylinder heads will work on a 305.

http://www.popularhotrodding.com/eng...s/viewall.html

 

906 heads have 1.94 intake valves. GM never made a stock vortec head with any other size. GMPP vortec "fast burn" heads may have bigger valves, but those aren't production heads.

 

I would factor in screw in rocker studs. Then use the rockers out of and LS series motor, they are 1.7:1.

You may want to consider reinforcing the trunion, or have a new trunion shaft made to factory specs, but a tad longer with lock rings on each end.

Ls rockers are known for spitting out the needle bearings. And the above will solve this issue, for less than aprox. $200 upgrades....

The bearing retainers will work themselves loose..Info for everyone here...They are a PRESSED in unit with no lock rings, which is why they fall apart.

First pic is a trunion upgrade, second pic are stock rockers-left is upgraded right is stock.

A good cam to use is the LB9 peanut hot cam..its a roller cam 88-89 only. Same one used in the 350 corvettes (Viscious Torque band). Sealed pro has it for something $180...

Just a few cheap recommendations.

 

I did not know that.

 

If you already have a couple of other projects going quicker, I really wouldn't mess with the thirdgen unless you are serious about the car. I always get caught up in the "snowball" of modding and start spending more money than intended. (Since I'm ALREADY there I might as well....) That sort of thing.

Bottom line is I wouldn't spend the time doing a head swap without doing the cam. And if your really going to do the whole thing then I wouldnt waste time trying to stay under .470" which means there will be valve springs and headwork involved. Getting them checked, machining the pockets for more lift, screw in studs, valve job etc. That plus some better runners, headers and y-pipe, an adjustable fuel pressure regulator to take full advantage of the set up.

oh...If you do, buy the head gaskets for the 350, not the 305.

 

does anyone still sell the vortec heads drilled for the stock intake?i need to 'appear'stock in my state.

 

http://www.chevyhiperformance.com/te...e_vortec_head/

 

will this even bolt to vortec heads?

 

i realize this is the tpi section but id love to see a magazine article where someone put vortec heads on a tbi engine and what all it takes to make it run right.and i mean EVERYTHING.
.too many posts on this site leave out important information like how to make the mods work with the computer.

 

There are lots od vortec tbi builds in the tbi forum. GM used a vortec tbi config on some bans in the late 90s or early 2000s. GMPP and others sell vortec tbi intakes, as well as 4bbl adapters so you can use any 4bbl vortec intake.

 

Scroggy dickens is the only long tube tpi base that will bolt to vortec heads. They are specifically made for that application.

There's some serious differences between coolant ports, bolt hole configurations..Of which make it "Nearly" impossible without a new base.

Another thing to factor in with vortec heads, is they're not designed to flow really any better past roughly .500-.550" lift. Not any better than stock heads. vortecs "really" shine below that lift point.
If your after a streetable street car, Then you really can't beat vortecs. This is what vortecs were designed for.

 

Appearing stock may be a big issue because there's some issue with Vortecs and the heat crossover. You cant make them appear stock on a TBI car. I have a friend I tried to convince to go Vortec, and he finally figured out that he couldnt in Cali because of the crossover if I remember right.

 

I drilled my heads for old style intake while they were off, ordered heavy springs for iron head LT1 engine, Tig welded about 1/4" to top of intake runners, then matched ports to Felpro 1206 intake gaskets.
You really got to want it, because it's a lot of work.
I finally bought TIPS Miniram III which then bolted right on.
Probably way too much for 305 though. I started with complete vortec L31 350.
There's a lot of 305 Vortec engines also, but I don't know if the heads are same as 350 or not.

 

The Vortec TPI intakes that Edelbrock/Scoggins Dickey sells are CARB approved, but the issue is the Vortec Heads. They do not have the Exhaust passages for EGR. To accomodate this, the Vortec intakes have a port where exhaust gas is ported from the Exhaust Manifold on the Passenger Side. So, to be truly Emissions Legal, you would have to install the Exhaust Transfer piping to the new manifold.

http://www.gmhightechperformance.com.../photo_14.html

That being said, If you leave the EGR mounted on the new intake, along with the solenoid, but block off the port and don't install the transfer piping, I doubt any inspector will notice. Mine passed emissions here in Vegas, and they are pretty strict here.

 

I had one vortec intake I bought from eldebrock and it used the vette hookup to ezhaust. That was a few years ago.
But like you, I just had egr mounted and plumbed, but cut off in .bin file.

 

There is a kit, by who, I cannot remember. All it is, is an egr relocation kit. Which you can do by yourself one. There are two ways to do it.

You have to drill into your exhaust and tap it/weld it on, on either mod. The first is to run a pipe from the manifold/header to a seperate egr block, then make a block off plate that is tapped and run a line from that to the eger block.

the second way is to use the first header/manifold option. Drill/tap into the pre egr system (exhaust channel the runs up to the egr), and pipe a line from the manifold/header to that channel. Egr is in the original location and functions as such..Though a pita should you need to remove the valve covers. Due to temps, it has to be a metal line.

Either one, the egr will function as it should. Most areas will allow such mods, so long as it functions as it should. As a visual inspection, because of AIR tubes, they might not even notice it.

The biggest issue is passing the emmisions test.

 

I don't like that rainbow (EGR transfer tube) over the valve cover. Vincent's pictures of the TPIS solution, shown below, is a potential alternative. (Not a bolt on solution, but a good idea to replicate.)

 

Nice piece ^