Guys...i have the chance to get my hands on some Vortec heads which I would be interested in putting them onto my L03. I am intersted to see what sort of 1/4 mile and HP numbers I would see out the following combo.

Stock L03 with the exception of a L98 cam, headers, exhaust, Intake (well would have to be a new vortec intake if the vortec's went on), 355 (I think) posi rear, stock 700R4 and stock converter.

What do you guys think???

Dave

 

I'd grab em up...
They're good heads...

keep in mind you are going to have to do some tuning.....

 

Make sure you're ready to spend money on extras.

You'll need a chip to bypass EGR, or hardware to make factory EGR work.

You'll see a drop in compression from the larger combustion chambers (64 over 58). You may be able to overcome this by using a thinner head gasket, but the matting surfaces have to be completely flat.

I'd upgrade the factory springs also. The L98 cam is OK for the lift, but those factory springs are just plain WEAK!!! Plus there's no spring damper in them. Both things that hurt upper RPM power.

Other than that it should work rather well.

 

Thanks guys....its even better that these things are FREE!!! ya needless to say I have a great buddy.

As for the tuning etc...I already have to do that after my L98 cam swap so that was something I was going to do in the spring anyways....

.....extras....what sort of extras other than the better springs???? and what do you guys think these extras will run me.

Also should I get much work done on them before putting them on...ie porting etc????

Thanks,
Dave

 

Do you plan on using these for a 350 down the road. If you do I would save them for now. If however you want them for your 305 because you are keepong it I would have the heads milled to achieve the correct chamber size as well as having the spring seats machined to accept a larger cam down the road. there are a variety of high performace springs that are really cheap that you can use. I would focus on what you want these heads to go on perminately. ERG will be a major factor to consider as mentioned above. My buddy runs these on his 305 with machined seats, milled .020 (I think) with a thinner head gasket and EGR delet in his chip. They are great heads and he can always put a cam larger than the LT1 that he is running now.

 

Go for that right now!
I usually use the Comp Cams springs #981-16 to replace the stock Vortec springs.
While there are alternatives available, I went with the GM Performance Parts TBI-Vortec Manifold. This allowed me to pipe in exhaust for EGR to retain emmisions compliance.
The increased flow of these heads will go along way, particulary with the headers and cam.
Some datalogging and tuning and you'll notice a huge difference.
Best of luck-
S-D

 

You pulled the damper out, or did you have the guide bosses cut down?

 

ShiftyCapone---> you are right on the money regarding the 305 / 350 debate. I was hoping that I could toss them on my 305 for now and then down the road when i do build a 350/383 toss them on there. But that is probably going to be like 2/3 years before I actually get around to doing up an engine at the rate that I work....lol....

 

Since they are free I would spend a little money now and prep them for your 305. Down the road you may want something better than the vortecs for your 350/383. Also, down the road, if you have the vortecs prepped for your 305 the smaller chambers may be to small for your 350 or 383 rendering the heads useless on anything but a 305 or a 350 with special low compression pistons. Than again you could always buy a new set of vortec's for a woppin' 500.

 

Yes- on the advice of the Comp Cams tech person, pulled out the damper springs. Have had no trouble- but a good thing to bring up- I forgot.
Thanks,
S-D

 

dave, better get a move on, I dyno'd at 178 HP last dyno day

and I still have stock cast log manifolds, stock intake, cam and heads to go

I'm gunning for 200 HP with still stock cam, intake, heads.

Oh yeah, I still gotta drop off those axles at your house, may pass by today, gonna be around, can chit chat about who's car is more purple lol

 

That is a great excuse to go out and buy headers right now. Full exhaust and you will see 200 no problem. Right now a pair of headers is saying "Slade buy me buy me"

 

rovic......geez.....long time no see/talk.....how are things man????

Ha ha.....ya sort of made up my mind last night I am just going to grab them and hold on to them until I build-up by 350/383.....its a much better long term strategy etc....

Ya Rovic....I should be sort of "in and out" this weekend if you know what I mean....drop by if you are in the area and If I am home we will chit/chat and if not just toss them on my driveway by the garage...

Thanks.....good to hear from ya again!

 

how did you pipe in the exhaust for the egr?

 

Like this-

I bought the ss braided out of a McMaster Carr catalog (about $30). The rest of the fittings came from the hardware store.
System works fine. I get no SES lights or anything.
S-D

 

so, you're taking the A.I.R. from the driver's side and using it for the egr, and using the passenger side A.I.R. for the cat?

i'm in the process of installing dual cats ... wonder if i could split the passenger side A.I.R. to both cats and get enough exhaust gas?

 

My original 305 had AIR into both exhaust manifolds and the cat. The new setup takes exhaust from the Drivers Side and puts it into the EGR. The AIR pump still feeds into the Passenger side exhaust header and into the cat.
I do not know if the AIR pump would supply enough AIR for two cats.
I wonder if cars that came stock with 2 cats had a higher volume AIR pump.
Anyone?
S-D

 

how are you plumbing the egr valve into the intake?

 

Got pics?

 

The intake has an EGR port cast into it. The exhaust gas goes intot he drivers side front, the EGR valve is on the Passenger side front. The exhaust then routes through the intake to just under the TBI. I only have a picutre of the EGR valve location.
Thanks,
S-D

 

what intake are you using?

 

That is the standard GM Performance Parts Vortec TBI manifold PN 12496821.
SD