1gary

A decent read.I approve of this link:

http://www.onedirt.com/tech-stories/...k-chevy-heads/

1gary

The link doesn't speak about adjust the push rod length when cutting down heads or the common machine work Vortec's need,but you guys know about that already.

1986Z28OWNER

iTrader: (1)

You sure post alot of Vortec heads... Do you use them on anything? You push the bowties on anyone that even mentions the word vortec. Do you even own a thirdgen? Why do you post here? A good read, yes, but its pretty common knowledge. Everyone is always so quick to say vortecs can be improved upon, That they dont respond to bigger valves, etc. I beg to differ, while it may not be cost effective to pour a bunch of work into stock castings They can be made into a pretty potent street head. Mine responded very well to both bigger intake and exhaust valves, However unlike alot, I spent ALOT of time on the bowls to accomodate the bigger valves, I left intake port openings complete stock, and changed nothing until the short side and showed considerable gains. 265 @ 0.500" 268 @ 0.600" (which was before I switched to a valve with a under cut and a back cut) The exhaust side was pretty typical of a small block check, but had a slightly nicer casting finish, I opened up the bowls to match the 1.60" valves, Raised the port roof approx 0.075" - 0.080" and opened them up around the valve guide area. I also completely eliminated the big bulky stock valve guide in place of some CHE bronze guides. Intake port cam in at 172cc's. far from the "Ideal" 195cc but it makes great HP and torque for what it is. Combined with a very mild camshaft and a very well thought out/light weight valve train it makes peak power at 5900, but dosnt suffer any signifigant drop until around 6500, and pulls all the way to 7000, with no issues.

1gary

Bought and sold dozens of Bowties to god I don't remember how many satisfied customers.........

Rule of thumb is .5 X CI=cc runner size.

1986Z28OWNER

iTrader: (1)

I call BS on that formula. Thats basically saying the the ideal head on a 632 ci BBC would have a 316cc intake port. We would sure have a hard time making Making 1300hp with that kind of intake port volume. Whether the actual number is bigger or smaller vs your "ideal" number I think its 95% based on the application.

five7kid

iTrader: (14)

Can we assume the formula only applies to Gen I/II SBCs?

Orr89RocZ

iTrader: (20)

Still gonna be application dependent. There are tons of rule of thumb equations out there in which you can find errors in... They are just guidelines...

vortecs can be inproved. One of the best motors i have seen was a 383 or so sbc that made 580 hp with a 230 deg hyd roller. Serious work done to heads with large valves and ported intake manifold to match. May have flowed near 280 cfm? I dont have the data saved from the forum it was posted.

redneckjoe

i thought it was a decent read.

people are always asking about vortecs on these forums.

it makes a good sticky type link.

thanx Gary.

GreggymacZ28

http://www.nastyz28.com/forum/showthread.php?t=56505

This thread answers about 98% of the questions i've seen asked on vortec heads.

skinny z

I think I've seen and read just about everything that's ever been written about Vortecs. Sort of a hobby I guess.
Having said that, perhaps the best advice to anyone interested in them and who doesn't want to spend a lot of money and time bringing them up to today’s standards is to go the aftermarket route. EQ Lightning, RHS, etc. all make newer versions that are have superior castings, fully machined and are ready to go.
Unless you're outfitted to do the requisite valve job for larger valves, porting and bowl work for increased flow, machine work for screw-in studs and new guides, up-grading springs, your dollars may be better spent on something new and up to date. How many of our forum members are equipped to do that? 86Z28OWNER (to name one) notwithstanding!
I'm not knocking the OEM Vortec in a street or race build in a mild application but if your targets are higher, then you may want to consider an alternative. I used them for decent results in one of my builds and gradually improved them until I wore them out a 2nd time. It was easy to realize about 375-400chp depending on how you interpret trap speed and dyno numbers. But spending more on them (and this doesn't include porting, home based or otherwise) didn't make sense from a dollar standpoint.