I've been following your thread for some time. I think it's great. A couple of things, however:

1. In your thread, you listed your cost at 612.00 Canadian and said that worked out to be about 390 U.S. That is a difference of 65.00 from the 455.00 I calculated. However, at the current exchange rate of 0.763825, 612 Canadian works out to be 467.46 U.S., 12.46 MORE than what I calculated, and I still believe you are way low on the initial cost of your heads .

http://www.x-rates.com/calculator.html

2. You cost your heads out at 25.00. That may be the case in Canada, but you forget "the rust rule". The further north you go, the harder the climate tends to be on cars' bodies. Therefore, you end up with a greater supply of available engines and engine parts. The further south you go, the easier the climate is on bodies, so cars tend to be driven longer, leaving less available engines and parts, but more available good bodies and body parts. Supply drives demand and price, so engines and parts tend to be cheaper in the north and bodies and body parts tend to be cheaper in the south.

When I was in college at the University of South Carolina, I had a gearhead housemate from Detroit. We were both broke and were always looking for ways to pick up an extra buck. After learning complete salvage yard engines sold for three times as much in Columbia as they did in Detroit, he started bringing two Chevy small blocks back from Detroit every time he drove his ratty pickup home for a visit. We'd then hunt around for a good cheap Chevy car with a bad engine, drop in one of the V8s sitting under a tarp in our backyard (the neighbors hated that!) and sell it. Paid for a lot of beer that way.

I still say if the average third-gen guy wanted to duplicate your heads, the initial cost would average out at 100.00. Even if it didn't though, your way would still cost more than mine in U.S. dollars, and that's using your figures.

3. Unless you didn't put it in your posts, you've never flowed the heads or put the car on the dyno. FBird 88 posted some impressive flow numbers for his heads, but he only gave the max numbers and didn't state what lift those numbers came from.

Max lift flow numbers are only relevant when you are at full throttle and in your upper rpm range. On a street car, the critical numbers are the mid-flow (.250" - .400") lift. Without them and dyno numbers, there's no way to compare the ported heads to the Vortecs.

This is especially true because you've gone to bigger exhaust valves. There's a reason exhaust valves are smaller than intake valves. When you change that ratio, you could be negatively affecting velocity. As an example, there's a head rebuilder on Ebay who sells remanufactured Vortecs with 2.02/1.6 valves. My buddy's Vortecs had cracked, so he tried a pair of these, as they cost less than the sdpc2000.com upgraded Vortecs he'd originally put on his 383. We were at a local high performance shop and got in a discussion with the owner about the big valve Vortecs. The shop owner insisted the bigger valves decreased velocity and actually flowed less than the stock ones and offered to compare the two on his flowbench for free to prove it. We jumped at the opportunity.

Sure enough, he was right. While the big valve Vortecs flowed a little better at .550" and up. the mid-flow numbers were significantly lower and the .200" - .300" numbers were horrible. Plugging the flow numbers from the two heads into his desktop dyno on my buddy's 383 shortblock showed 9 more max hp, but the average was down 13, average torque was down 21 and the torque curve, broad and flat with the stock vortecs, was terrible with the 2.02/1.6 Vortecs.

Now, I don't know whether the valve changes you made would have the same effect on your heads, but I don't know that it wouldn't, either. Without flow and dyno numbers, there's no way to tell.

Again, I'm not trying to denigrate your efforts, but you can't just flatly state this is the be-all/end-all solution.

Splitting the difference between your 25.00 initial buy in and my estimate of 100.00 comes to 62.50. Adding that to your heads' U.S. cost of 467.46 comes to 529.96, so let's set the real world cost of doing the heads your way at 525.00. Also, it's important to remember that there's a risk of the used heads you start with being unrebuildable. If that happens, you're out the cost of the heads (62.50), the cost of replacing them with another set of rebuildable heads (another 62.50), and a minimum of 50 non-refundable bucks at the machine shop for the cleaning, magnafluxing and pressure testing that reveals whether the heads are rebuildable or not. That's a risk of 150.00 with probably a 1 in 4 or 1 in 5 chance of happening.

Back to the point, taking that real world 525 cost for porting the heads compared to the 600 cost of the Vortecs (including shipping and milling) leaves a variance of 75.00. Adding to that the 85.00 difference in the Vortec and non-Vortec intakes gives us a project variance of 160.00

You said your porting took 20-25 hours. Using the lower, 20 hour figure, your 160.00 savings yields a time value of 8.00 per hour.

Additionally, to save that 160.00, you must:

a) Risk losing 150.00 if the heads are bad

b) Risk screwing up the porting and ruining the heads or possibly harming your engine with mismatched ports.

c) End up with an unproven head which, even if done correctly, still may not make as much power as off-the-shelf Vortecs.

d) Put a lot of time into a dirty, uncomfortable task for a low hourly savings yield. My hands would be painfully numb for hours after I'd port and it took days for the metal/oil taste and smell to go away.

The only way this makes sense if if someone has access to the 081 heads virtually for free, has some experience or at least someone to advise them with a ton of experience, has a good place to work on them and already owns the intake they plan to use.

For the average Joe who has to hunt down the heads, has never tried anything like this before, doesn't have access to a shop or at least a garage and is planning on buying an intake, anyway, I believe porting vs. Vortecs is "penny wise and pound foolish". The potential savings just don't offset the risk and time/grief investment.

 

Well, all I can say is that you are apparently not the sort that enjoys a little challenge in your engine building. I have never found head porting to be rocket science and in my experienced opinion you are grossly overstating the difficulties. It has been my experience that any normal person, male or female, who can persevere a little bit until they get a feel for a die grinder can also turn out a nice pair of heads.

DOZENS of us on this site have already done it. Their efforts have produced good power, even if they have never flow benched the heads.

95% of the cars in the wreckers here in Canada are there because they were totalled in a wreck, not because they rusted away. Since Chevies are so common I don't understand why a set of 305 heads are such a prize in the south. $30 or $40 gets a set here.

A place to do the work can be a problem for people without any sort of facilities but that is a given that has nothing to do with the question at hand. If I didn't have a garage to do them in I would wait until the weather was nice and do them outdoors.

Anyway, I really hope you find the heads you want at the price you want to pay. As we agreed, the prices are at last coming down somewhat.

 

The cars up here crash due to the icy roads, eh!

 

Just got the latest issue, there making some sweet hp out of that 305! 256hp at the wheels.

 

I just picked the September issue up last night. not only was it the 305 TBI part II update, but Kandied was featured in the issue as well!!! I'm fired up now... out to the garage to work on go fast parts!!!!

:lala:

 

330 HP 378 TQ at the crank according to them (CHP) seems kind of high seeing how the 350 HO has about the same figures.

 

I beieve them. They are running a huge cam and they did port work on their vortec castings. The HO 330 could be so much better with a bigger cam and slightly worked heads.

 

Yep...I think so too

 

Since we have a new sticky I am gonna let this one go. It iwll be linked in the "new to TBI" thread at the top of the page. I was going to clean up some of the posts that weren't relavent to the topic at hand but since we are not going to keep this a stand alone sticky it is not needed. Thank you for all those that replied and participated.

 

you know, one thing that is potentially misleading about that article is the porting they did to those vortecs. they kinda downplayed it and didn't give a lot of details, but, if you compare the before and after flow numbers, they got MAJOR flow improvements out of those heads, and that takes MAJOR port work. I've called and emailed the guy they said did the work, but haven't gotten a response. i don't think someone bolting on the same parts they did without the head porting is going to see anywhere near the hp increase they did.

just once, i'd like to see a magazine do a buildup with out of the box parts, which is the way most of their readership is going to have to go. if they want to go back later and modify those parts, then show the additional power that got, all the better, but i guarantee you there are a lot of people reading those articles who skipped over the head porting and chip tuning, and it's because the article was written in such a way as to be conducive to that.

 

Good point. We all know that you can doulbe the flow rates on the exahust side of the vortecs with port work. The intake is pretty much set as it sits but the exhaust can really be worked over.

 

Super Chevy has a segimant thats been going on for about a year or so that is called danger mouse where they build a 350 with different parts everyweek. Each part they use is completely out of the box. The articles they are doing now are a little over the top(like 600hp tunnel ram setups), but the first articles they did were very simular to most mild 350's you see on this site. I doubt anyone will ever do it with a 305 though.

 

i LOVE danger mouse. So many different combinations, all tried in a controlled environment. i believe that and the goodwrench quest offer more good info for everyday joes than all the other engine buildups put together.

 

Sorry for the oversight if someone had posted it...
http://www.chevyhiperformance.com/te...ion/index.html stew

 

Back from the dead!

 

Just some info on Pro Topline, they did go under bought out and are now called RHS (Racing head service) www.racinghead.com

 

Racing Head Service was a big-time player back in the 80's and 90's.

With the NEW GM vortecs out, though, I don't think Pro-Toplines are the way to go. The new vortec has all the improvements the Pro Toplines offered, and they flow better, too. The price is low as well.

 

sean, what new GM Vortecs are these you speak of? I hadn't heard anything about that yet, what's the casting number on them? What applications? Thanks.

Jim

 

No applications, except maybe Mercruiser or Volvo Penta. They are sold under GMPP.

 

Are you talking about the bowtie version of the vortecs?

 

Yep, it is only speculation, but why would they not be used for a marine engine. They already have all the good stuff.

 

They did a story on them in December, 2005 issue of Super Chevy.

http://www.superchevy-web.com/techni...tec/index.html

The only potential issue I see is the 2.00" intake valves. Depending on how far apart the intake and exhaust valves are set in the heads, there may be shrouding, or even actual valve clearance issues on an L03.

I spoke with one of the engineers at Dart last summer concerning their new, 56cc small port heads. He said they wouldn't work on a 305 because aftermarket heads set the valves further apart from each other in the chamber than factory heads do. It's going to depend on where GM set these valves in the chamber.

The flow numbers are awesome, though.

The only reasonably-priced aftermarket head I know of with comparable numbers are Edelbrock Etec 170s, and they cost 400.00 more.

 

Yeah, although they also have two port sizes, which is nice. You can pick one that nicely fits your engine.

 

hmmmmmmmmmm .... the article said complete heads for around 700.00. Can't find 'em for that though.


sdpc: 489.95 ea.

http://www.sdpc2000.com/catalog/3129...inder-Head.htm


crate engine depot.com: 478.10 ea.

http://www.crateenginedepot.com/stor...21-P898C0.aspx



At that price, I'd absolutely shell out the additional 1-200 bucks for the Edelbrock Etec 170s.


Summit: 529.50

http://store.summitracing.com/defaul...h.asp&N=400065


Doug Herbert: 539.99

http://www.dougherbert.com/etec-alum...facturers_id=8

 

Both the Bow-Tie Vortecs and Edelbrock E-tecs come in two port sizes. I believe the bigger, 200cc+ port sizes on either head would make less power below 6000 rpm and considerably less torque across the entire powerband on a 350 or smaller. I would go with them in a second on a 400; the question is, which on a 383? I'm leaning towards the smaller ports, as i tend to prefer big cube engines that make best power under 6000 rpm.

That Etec 170 is an amazing head. They blew the Super Chevy guys away when they put a set of them on Danger Mouse. they said it was the best set of heads they tested on the engine; bar none.

 

the port size will depend on lots of things. Partialy the cam and motor. Considering the small ports flow almost exactly the same as the larger one, until .500 lift, you would need a pretty potent combination to really take advantage of them. If you are running a large lift cam, on a big motor spinning some RPM, it really makes sense to go with the large ones. I'm really supprised at the numbers the small port version put out. I was not expecting to see that kind of flow out of the small port version.

 

Well, as I understand it, the advantage of the LTI design (which all of these heads use), is that it uses velocity, not port size, to flow a lot of air, leaving you with the torque and throttle response inherent in small port heads, but flowing as much air as heads with much larger ports.

 

yup, that is why the raised runner design is so nice.

 

Damn, way to bring a thread back from the cyber grave yard. I almost forgot what a hot issue this was when it first came out.

 

To keep a thread alive!! IT"S ALIVE!!!

Did CHP ever comeout with that september 04 issue and explain what all they had to do to get the numbers they did?

 

They didn't do anything extra to get those numbers, however they did finally come out and say that the TBI swtup was not optimal. Then they used Turbo City to dyno it along with 350 TBI injectors to fuel it.

 

awesome info here

 

need 350 injectors?... anything to do this but stick with the 305 injectors? i was looking into going vortec but i dont know what i really need...

 

I honestly think that they could have gotten an honest 275hp 300tq out of that motor with a better intake and headers. I really don't think they truely thought about getting the absolute most out of that motor.