I'm considering a quick fix on my car. I have the heads pulled off and I'm considering putting the Vortec heads on there that I have lying around. I don't want to have them milled and I don't want to change the cam. I just want to put the thing back on the road ASAP. What would be the performance result of having the stock cam and Vortec heads with the 64cc chambers?

The machine work for the heads would be $125 to mill the Vortecs, or $335 for the stockers (they need a valve job, badly). Would this quick fix be better, worse or the same as the stock set up?

Before the discussion starts, the cost to reinstall the stock heads would be $457 and to install the Vortecs would be $623 with machine work or $498 without the machine work (includes cost of manifold and EGR equipment).

 

At 64cc a 305 will run like crap. I only paid 60 bucks to get my two Vortecs milled. But if you run the Vortecs you'll need the intake to match.

 

Man thats a lot to mill. For .020 my local shop is like $30 / head. You might look around. Run the FPP-1094 gasket too, its only .017 compressed so that'll give you some more compression back if you dont have them milled. Id still throw an LT1 cam in it, for $35 you cant beat it. Like 89 said though, vortec manifolds get pricey. I think I paid $180 for mine over the summer, the regular performer is a little cheaper.

 

I'm hard up for money right now. Plus, every day I spend waiting for a cam to come in the mail is another day that I have to borrow transportation.

Here's a question, though, is it ok to have the roller lifters cleaned by the machine shop along with the push rods and valve covers? I wouldn't want to place the dirty lifters on top of the new (used) cam. I'm telling you guys, this engine was not well maintained. That's one reason I don't want to pour much into it, I'd rather just get it running so that I can start building an engine on a stand.

 

you can clean the lifters your self very easily. 99% of the gopp on them should be external and whatever small amount that may have gotten inside will be difficult to clean out anyway. wipe them off really well using a degreaser. make sure you get all teh degreaser residue off teh lifter when you are done. the rollers shoudl turn easily with yoru fingers. if they seem to stick or seem too tight or roll roughly then replace them, there is no need to wipe out a cam with a bad lifter. all you need are stock replacement lifters that can come from any stock roller vehicle. if you look in the classifieds on many boards you will see guys selling stock LT1 liufters(actually the same lifters we got) for very cheap.
the stock 64cc chamber will not make your car run bad at all. you will lose some power from loss of compression, but you can compensate for it by runnign more timing(lower compression can see more timing without knocking). so if you are on a tight budget it may be jsut as well to skip the milling since it sounds liek you want to replace the motor soon anyway.

later
tim

 

Thanks, NJ.

All cost options being considered I think I will go ahead and have the stock heads repaired for about $200 and put them back on. I'll hang on to the Vortecs and either put them on a 350 that I can patiently build on a stand, or sell them and start focusing on a TPI or LT1 type build.

I know that having the stock heads repaired and reinstalling them might seem ridiculous, since I have so much of the motor torn apart anyway, but it's by far the quickest and least expensive alternative. This is my daily driver and I just want to see it get back on the road. Plus, this will allow me to fix up my 3:23 posi disc brake rear that much sooner.

What I really need is a second car and a hell of a lot more money.

 

Just to let you know.....

The compression ratio will only drop to about 8.7:1

The stock is 9.3:1

That's just over 1/2 a point. That's not a big loss.

If you still have the stock ECM, you can just set the base timing a little higher (~6*) and it'll be fine. The reason is, a lower comp. ratio is less likely to detonate, which allows for more base timing.

If it's just a quick fix, don't worry about it. The increased efficiency of the Vortec heads will MORE than make up for the loss in compression. It's not like you're putting 76cc chambers on your motor.

IMO, you're gonna be throwing $200 out the window by rebuilding the stockers. Sell them for $50 and let someone else worry about them.

 

You make sense. The thing is that I have the money to repair the stockers, I don't have the money to do the Vortecs. I know it doesn't seem like a big difference, but we are talking about $300 and a guy whose just recovering from Christmas and a 3-year-old's birthday. Plus I need new tires, my homeowner's association dues are past due, I still need to pay to register the car...etc.

 

Yea I know the feeling.

I also have a 3 yr old that got a hell of a lot more for Xmas than I ever did. And I mean if you add up all the stuff I've gotten over the years, he still beat me with just the stuff he got this year.

I'm gonna have to buy another house soon so we have more room to put all his crap in.

 

Pwaaaahahahahahahaha!!!!! That's exactly what my wife and I just did, which is what led to our homeowner's association dues. We had to move from a 3 bedroom/2 bath house to a 5 bedroom/3 bath house just so that the kids (a 3-year-old boy and a 1-year-old girl) can have a "playroom". The upside for me is a huge garage and a new office.

 

For the money you will spend on the stock heads you can buy a vortec intake and an adapter plate. With the lower compression ratio I would play with the timing some, you could probably get by without running any egr. Just my .02.

Steve

 

Im glad someone posted more on vortec heads.

Im in a similar position...Im running a L03 (305 TBI on my 91 RS...its bone stock)

I have a pair of Vortec heads I can pick up for $200. First of all, is this a good price?

Secondly, before I make the purchase I've been running around the internet and various postings trying to find a part number or some information on a compatible intake for the vortec heads...it seems many refer to Edelbrock's Performer series...

-Does anyone have any part #'s for me and some results of the vortec heads/intake combos or can you suggest OTHER intakes than Edelbrock?
-Will I need to replace my valve covers to allow clearance?
-Is there anything else that I MUST replace when installing Vortec heads.....like the intake, springs and so forth?

 

$200 is a very good deal on vortecs. Very good, even if you buy them and resell. Stock valve covers are ok, and the stock springs are OK if you keep it under .460 lift on the cam. Any thing over and you'll need a better spring and seat work possibly. You'll have to get a new chip, the stocker will run ultra rich with a larger cam (heads arnt overly useful with the stock cam).

 

To bad you did not post about a week ago I just sold the long block out of my GTA for 250. It was in perfect condition with 98,000 on it. Sorry I just had to post this because I thought I was the only one that missed out on good deals. Seriously though I would scan the local junk yards and internet. You can pickup decent l98 heads for next to nothing. If you can find a set of bare heads, mediocre replace parts from autozone will produce a nice mild valvetrain for a street machine.

 

Chuck, I have a stage II chip already. So I don't really expect too much of a problem. Thanks for the input.

blain

 

i hear jon's footsteps........

 

Hmmm, not really sure where to start. You're right about the compression loss not being that big of a deal but it's still lost power. I wouldn't spend the time to install a head that lost that much in compression unless it had a power adder, whoosh .
You are way off with saying set the timing higher. Yes this is true when you lower compression but dude, we're talking about vortec heads. Not only do vortec heads require less timing to make the same power, but they don't have EGR so the ecm will add timing for that as well. Moving from like 2 to 8 degrees just because of compression loss and not taking into acount the rest of the picture is the wrong approach.
The above can also be 4 or 5 degrees off if he's running stock exhaust manifolds. Lots of weirds stuff happens when you change the heads, weirder when you change the cam, worse when everything else becomes the bottle neck.
Yeah, custom chip my ****, lol. BIG footsteps but I think I'm just going to give up that battle. Let people think what they want and spend their money where they feel it works best

 

Jon, if there was confusion..my chip isnt a custom chip but bought thru some company i dont recall their name. If thats what you mean by custom then i gotcha.

My present setup is bone-stock. all but exhaust headers, full exhaust 3", open air element on a TBI 305 in CA.

I have a set of vortec heads im picking up for $200, a matching manifold with EGR so that i may plumb from my headers.(although I havent been able to find a matching one...still need the casting #'s of my prospective heads). I plan on keeping my stock cam.

I want to know what problems I can expect from this combo as well as what power. Or should I just toss the idea in the trash seeing as I have about enough spare change to get the manifold/heads/gaskets/oil pump as im changing out my rear main seal. Perhaps I will have enough for a valve job and some springs. But I dont think i can afford the heads and headwork, manifold and the cam in the same paycheck.

Thanks Jon
blain

 

And how many times have you changed heads?

First off I said ~6*. I that could me 4* or 8*. He's just gonna have to try it and see.

Second, I don't care WHAT heads they are, dropping your compression that small amount can be made up by advancing the base timing a bit. Especially since it's something that he wants to do TEMPORARILY. He said that. What you're talking about is MAX HP. And that's true, but better said is 'the Vortec heads are less responsive from more total timing for maximum power.'

And how does not having the EGR cause the computer to advance the timing more than stock? It is true that you will get less detonation because there won't be that hot air going into the intake, but it would be no different than running 93 octane gas and not getting any detonation. The ECM still has a set limit as to how much timing it will advance, correct? It's not like it keeps going up until something breaks. It still has certain parameters it has to follow.

Granted what I'm suggesting would not hold true if he was looking for peak HP, or a drag car. But he said....
I'm just telling him how to get the quickest results for what he's trying to do.

 

My head has never been changed. I like it right where it is, between my shoulders .
You were unclear with what you had said. It sounded like you told him to advance it another 6 degrees as a temp fix. If anything, the safe side is to leave it stock. THAT is the temporary fix.
What are you talking about?
False, you will get MORE detonation because there won't be that hot air going into the intake. Oh yeah, and it's not air anymore, air is the term reserved for nitrogen and oxygen in a nice healthy life sustaining ratio. Exhaust gases don't burn hot because there isn't any oxygen to complete the combustion process. By not having as much oxygen you can run more timing to "make up for power loss" just like compression loss.
The ECM doesn't have a limit if you're changing the base timing. There is no crank or cam position sensor which is good and bad. Good because you don't need a "custom eprom" to tune your car. Bad in the sense that you could advance the dizzy so far that the car just detonates to death. Thankfully you've got a knock sensor so it won't do that UNLESS you bridge the gap of it's max spark retard. There is a limit for how much timing the ecm can use and how much it can take out when it detects knock. Lots of thresholds which should never be tested off of a test bench (unless you know what you're doing).
So by example, the ecm has a max timing of 40.1 in the stock calibration of the ANTT BCC. That's assuming you've got 0 base timing. If you advance it to 8 the ecm doesn't know that so when it's running 40.1 you're poor motor is looking at 48.1 degrees!!! You had better be running a low compression funky cam and LOTS of EGR duty cycle.
Vortec heads will want more timing in earlier to "feel right". If you want a TEMP solution and you don't have any way to monitor detonation or performance, keep it no more than 4 base. Like I said, no EGR and the ecm will advance your timing thinking there is less oxygen in the c.chamber. You can get away with more timing with aluminum heads because they're less efficient at keeping in the heat. Vortec heads are wonderful designs and going down a half point in compression isn't going to make as much of a deal as the actual head. Oh yeah, and even if you were driving around nice and light foot that's where the most timing comes in. You can get away with setting the base timing high if all you're doing is idle and WOT (guys like to run fixed timing dizzy's at the track) but high vacuum means more timing.
I guess you can take it or leave it. Do what you want but to just move the timing up 6 degrees from where it is now is the wrong approach no matter how you look at it. Good luck and don't worry about the compression so much.
Obviously set the base timing to where it feels right but check it with a scan tool. Knock counts should be no more than 20 and NOT incrementing. Maybe 1 every 10 minutes or so but that's most likely the self test that the ECM does to make sure you're knock sensor and ESC are working. Oh yeah, and monitor the spark counts/knock counts while you're driving light foot. Only a couple times punch it to see if knock goes scy high. Hopefully it won't and you're good for now.

 

See..... I don't know how to change the timing curve on a CC dissy. I've only delt with mech/vac. I imagine the same concept applies, just approached differently, correct?

But I can tell you that I've taken EGRs off of engines and replaced them with a blocker plate, and I was able to advance the base timing by 2-3* initial. Of course I had to use stiffer springs or bigger bushings on the weights to keep the total timing down, but there's my proof. As a matter of fact, I just did it last fall on my '83 1/2 ton. Maybe that only applies (works well) to carbs?

I'm aware of the knock sensor. I wish I had one on my truck. It would make stuff so much easier. Perhaps one day when I rip the TBI off my car to use a Commander 950 on the Camaro, I'll throw the TBI on my truck.

You answered my question by saying it does have a cut off as far as total advance. Since he's still going to have a knock sensor, he'll be able to advance the timing. Although I must agree that running a total of 36* would be all that's needed. 40* or more on an otherwise stock 305 would not prove well with the Vortec heads.

As I should have said..... this would be all relative to wether he's really that worried about it loosing some HP by dropping comp ratio. I should have stated that earlier.