Hey guys...

I finally got a car!

Now, the question is - I've got a 96 vortec 350 motor, that I'd love to pull the heads and intake from and swap onto this 305. The vortec heads are completely stock, and have no porting done. I already have a squarebore Edelbrock intake that properly mates to the heads, and a adapter plate to get the TBI mounted correctly.

I'll be doing an EGR delete along the way too, anything to worry about other than the occasional SES light?

Finally, I'm looking for some guidelines on how to best port/polish the vortec heads. There are 1 3/4 mac headers, custom y-pipe, and 3.25" pipe thru a random tech hi-flow cat, down to a mac cat back system with 3" tail pipes. I think the heads will reallly have room to breath on this car. I also plan to do the ultimate TBI work as well. Free power is good power!

Any help is greatly appreciated.

-Dan

 

I believe David Vizard has a book out on porting Vortecs, but that's not 100%. Check on amazon and see if you come across anything.

You're gonna need a lot of tuning, so if you burn a chip or take a shot in the dark with a mail order (I do not recommend this) just disable egr and you wont have any problems with SES lights. Good luck on the vortec swap, if you have any quesitons let me know.

 

I'm sure someone else will chime in, I'm surely no expert here, but I've read that the Vortec intake port is already about optimal, or better than you're going to make it. I think you can port the exhaust side tho, and for that I would recommend reading Sitting Bull's write-up on how to port the 416 heads.

 

If you swap Vortec heads from 350 on to a 305 won't you lose a lot of commpression because of the larger cumbustion chamber?

I am asking this as a ? because I really don,t Know the CC of the 305 or 350 Vortec chamber. -Rod-

 

Darn good point on the compression issue.... I wonder what that will do too... 305 has 64cc chambers, right?

Here are the specs for the heads I have:

10239906...96-up...350.........."Vortec 5700", "L31", 64cc chamber,170cc intake port, 1.94"/1.5" valves

I haven't had the valve covers off the Z yet... heck, I haven't even taken delivery of the car yet! I leave for RI on Monday to pick it up and drive back home same day. Should be a fun drive.

-Dan

 

You can keep the compression up be just dropping the whole 350 in there. As far as porting the heads read part one of the vortec head swap article in the may or june issue of chevy hi performance where they put vortec heads on a 91rs 305 tbi.

Steve

 

Have the heads milled .020 and then run the FPP-1094 gasket which is .015" compressed. This will allow you to use the intake without having it machined because of the new height of the heads, and you'll keep most of your compression.

But a good point was brought up, if you have the 350 why dont you just use that?

 

Thought I'd chime in and say nice color!! Hugger Orange?
Anymore pics of the car?

 

Ive heard from so many people that porting a vortec head will only make them flow worse. Ive also heard that stock vortecs outflow the junk world products S/R heads

 

So since we have some vortec knowledgeable peeps up in here...
Is saying from CHP about the 906 casting vortecs not flowing well is false?

http://www.chevyhiperformance.com/howto/97458/

 

Yes, the 906 versus 061 casting statement is false. CHP later went on to correct that.


No, porting vortecs does not make them flow worse, at least, not if you do it properly. They are nice port designs, yes, but they aren't perfect. Get in touch with F-BIRD'88. I believe he has Vortecs that flow upwards of 245cfm.

I third the notion of using the 350.

 

Also remeber, flow is not everything. what really makes the vortec design shine, is its combustion chambers. That coupled with porting them, to give them some steller flow numbers, makes for a great combo.

Case in point. Look at the HP numbers being put down by mills with FastBurn alum. heads on them. Given the 'not so hot' flow numbers people keep saying they have, they put down great power numbers.

 

All good points.. I'm not sure which casting I have, but I do believe that the heads I have are sawtooth pattern vortecs.

As for just swapping motors... you might actually have something there... Just much more work than simply swapping heads... esp since I have a 5spd behind the 305. I wonder what the power difference is? 1996 vortec vs. 1990 305 TBI? I'll imagine its significant enough to notice!

-Dan

 

Best cam to use for a 350 vortec motor? I've got the Edelbrock 2116 L31 intake (idle-5500 or 600CFM). I'm uncertain if the heads have been machined for additional lift... matter of fact, I'd rather assume they are stock.

What cam should I use if I slap in the whole 350 as a complete package? Would a L98 cam serve ok? How much would an LT4 hot cam cost? Where can I purchase one?

Thanks guys... I can't wait to work on this thing!

-Dan

 

The hot cam would be a great choice for that motor, but do not there will be alot of computer work needed to get it to run well.

in the cars with the hotcam and fastburns that combo will make 385hp+

 

Keep in mind, the true fast burn alum. heads also cost ~1200 for a pair. I'd save the extra 300 or so and get AFR.

 

i was comparing a set of ported vortecs to the fastburns. the fastburns are basicly alum. vortecs, with a little more flow. ported vortecs should produce at least the same power levels.

 

Will an ultimate TBI be able to feed a 385HP motor with the stock injectors after burning a new chip? (anyone out there have a prom burning KIT for sale? )

Secondly, assuming my vortec heads are STOCK (not machined for 500+ lift cams), will I be able to just install the LT4 hot cam and run without spring bind?

Thx guys!
-Dan

 

no it won't.

IF it is doable, it would take a 670cfm unit, with the 90pph injectors. and lots of tuning.

 

Whats the GM P/N for the "90pph" injectors? Thanks for helping me out Dewey!

-Dan

 

I dont' have the part number. I would just get the holley TBI kit, with the 670cfm TBI unit, and then get the 454 application, it will have the large injectors.

 

That is a good point. Plus with the AFRs, you can remain smog legal (if thats a concern) AND you dont have to use a vortec specific manifold.

 

I would suggest dropping the Vortec 350 in bone stock. Get it running well with the stock TBI. Then upgrade. Too many changes will likely result in frustration and carburation.

Why? There is a steep learning curve for prom tuning which is fairly essential to making it run right. One step at a time.

 

Brent-

I've used WINALDL for monitoring before, and I have light burning knowledge. I'm a computer guy by trade... can it really be that hard? Question is... will the car be driveable with the 350 vortec and the LT4 cam running on the stock 305 TBI PROM?

-Dan

 

doubtful.

with a 206/216 .450 lift cam, in a stock headed 305, it would hardly run at all, and was not drivable, it took quite a bit of tuning.

 

Its not hard. The learning curve is steep because the information is not contained in one book. Much searching and reading must be done. It will be much easier to start off with a stock engine and TBI.

Question is... will the car be driveable with the 350 vortec and the LT4 cam running on the stock 305 TBI PROM?

LT4 Hot cam? No.

 

Ok, point taken. Now, if I leave the hot cam out and begin learning how to tune on the stock 350 vortec motor... will it run on the 305 TBI chip then? If not, can I just hit a local yard and pull a 350 TBI chip from a early 90's truck to get by on until I have all the chip burning hardware?

Thanks guys... I really appreciate the help.

-Dan

 

Chapter 9

 

Amazon will deliver that book to my door next Tuesday! Thanks for the info. Its pretty cheap too at ~$14.

-Dan

 

Car Craft, July 2003, had a good article on porting Vortecs. An extremely short summary would be to leave the intake alone, reduce the face of the exhaust valveguide and have the valves cut with a 30 degree back cut.

 

http://www.carcraft.com/techarticles...ort/index.html

It's been proven time and time again....

Don't mess with the intake ports on Vortec heads. As you'll see in that article, the guy is an expert who's been doing this for years, and even he didn't gain very much CFM.

The exhaust side is where it's at.

 

I don't think anybody read the first article on the vortec head swap on the tbi camaro. They were able to gain at least 20cfm on the intake ports and much more on the exhuast. Is it worth it on a 305? Maybe, maybe not but at the very least clan up the bowl area under the valves.

Steve

 

dont port vortec heads!!!!! they have very sensitive combustion chambers....FAst BURN..if you port them you will ruin them.

 

I don't think anybody mentioned anything about modifiying the combustion chambers. Just read the first artical about the tbi camaro in CHP and you'll see what I was talking about.

Steve

 

I think any worries over chamber size on Vortecs is largely unnecessary. The books say they are 64cc but I've read elsewhere that they are actually more like 61cc, which is not worth worrying about compared to a 305's 58cc chambers.

But I'd just swap the entire 350 in as well. Perhaps you can make the 96's computer work on the Camaro?

The guys on the TBI forum will probably be able to give you even better info than we can here.