Can I put 2.02 & 1.60 valves in Vortec heads? I've heard that 2.00 & 1.55 is as large as you can go, but don't even remember where I heard that at know. I'm building a 388ci motor and want to use the Vortecs but fill they need more flow than the 1.94 & 1.50 valves will allow. If I can't use the Vortecs I guess I'll be saving for quite a while to get the AFR 190cc intake angle plug heads, I know that these will flow like I want but damn $2500 is a lot to give fulley CNC ported or not. Would really like to get by with some P&Ped Vortecs with larger valves if posable. If anyone knows please let me know. Thanks, Bobby

 

You can install bigger valves in those heads, but I dont know if the gains in power would warrant the cost. I have heard, and read to many times that it really doesn't help. With the added CI, maybe it would help you out.

 

do an ebay search on vortec heads. there's a guy on there (amperformanceheads, i think) who sells vortes with 2.02/1.60s. he has a lot of feedbacks and they're close to 100% positive, so i think you can buy from him with confidence.

i wonder about that, though. i thought the whole benefit of vortecs was velocity. would larger valves affect that?

 

If you go buy a book called

"How to build Max Power Chevy Small Blocks on a Budget" by David Vizard, you'll see that they're not real happy with bigger valves.

He ran 2.05" intake valves and pocket ported them. The result was so minimal that he couldn't even plot the line on the graph because the there wasn't enough difference to be able to see. The two lines on the graph would have looked like one fat line.

The only way he got a noticable improvement was from fully porting the heads.

The exhaust was a little different. It responded a little better to pocket porting with 1.6" valves. Not a huge difference, but at least enough to show on the graph.

He had to do a full port job on the exhaust port also in order to see a noticable improvement.

So as you can see, unless you're going all out with a port job, don't bother with larger valves in Vortec heads.

Here's a link on what to do if you're interested in porting them.
http://www.carcraft.com/techarticles...ort/index.html

 

Yeah, bigger valves won't really help, you're better off spending money elsewhere in the motor. Vortecs are nice heads, but the AFR's blow them out of the water. I've had both and the AFR's are my first choice. They may be exspensive, but they're worth it IMO.

 

Get some Pro topline 200cc Iron Lightning heads.

AFR flow on a Vortec budget.

www.protopline.com

 

if you're going to use vortec heads until you get the money for afr's, i'd stay with the stock vavle sizes. you'll have enough airflow and at the cost of the valve swap, even with porting, i wouldn't expect enough airflow gain for even a 20hp difference. i'd just recomend having them machined for the clearance issue, port them, and run them as is.

 

I copied this from that other post you were asking about it, so instead of retyping my response here it is:
I will tell you from personal experience about Vortecs with bigger valves and a crazy port job. I bought mine and they were originally set-up for a .600 roller. I was using a smaller soild flat tappet so they machined the spring seats for a double spring good for .575 lift and while they were at it installed 2.02/1.60's plus a super, super job on port work to the naked eye. These heads looked great but I then took them to my local shop to get checked out before I installed them a a different mill. They ended up flowing a best of 199.4 @28" at .550 lift. on the intake and 180.3 @28" at .550 and .600 lift on the exhaust using the SF-600 flow bench. now compare these numbers to what these heads flow out of the box untouched and you be the judge. I ended up selling the whole top end I had just bought and got some AFR 210's instead which just got dropped off yesterday for checking and flow testing. The biger valves even with the port work just made the velocity go to helll in a hand basket and realy hurt performance in a big way. So if you have vortecs do some porting of the exhaust side since in stock form this benefit but do not install bigger then factory valves since you'll hurt instead of improve. Scoggy Dickens sells Vortecs for $625 set-up for a .550 lift which is a super deal if any are thinking about it.

Oh, here's a link to head flow charts if you have'nt already seen it, take my specs and compare them to the vortec flow rate in the link and you'll see first hand how bad of a deal it is. http://www.chevyhiperformance.com/te...98/index4.html

 

if you search the TPI board (or was it the Aftermarket Product Review board????) you'll find a thread that got pretty extensively into this a couple weeks ago where a guy asked for opinions, then argued with our replies. Within that process though, a lot of useful information cropped up that is worth reading.

 

Vortecs need additional port work if you go 2.02/1.60. Without it they will flow WORSE than stock. I would go with the shelf 190cc fully assembled AFR's for $1400 and do port work later as your budget allows. They are probably close to what you need right out of the box. They are are pretty amazing right out of the box. Not to mention the weight saving over the Vortecs. Vortecs are great heads for their application such as a TPI motor. They flow the perfect rpm range for a modified TPI motor where the upper range is 5000. Beyond that is where AFR's add gobs more HP.