I've got a new set of vortec heads on the way for my 350 rebuild. I've covered all the bases when using these heads (intake, valve covers, gaskets,ect.) but I'm still worried about my cam having to much lift. Everything I've read said .470 is the maximum lift while using the stock spring setup. Quoting an article from Customclassictrucks.com The maximum amount of valve lift before the spring retainer hits the valve guide seal is 0.530 inches. It is generally accepted that 0.060 clearance needs to be maintained between the retainer and seal (.530 - .060 = .470 max lift). My cam is Comp Cams X4 262H gross valve lift intake .462 and exhaust .480. Will the springs handle the extra .010 inch? My head man said I'm OK as long as I don't go over .500 lift. Do any of you have any experience with this? I hate to spend any more money I'm already well over my budget. This rebuild started out as a simple cam swap!

They measure 520-550 acceptable lift withOUT the valve seal depending on the head. I measured a set of 305 58cc vortec heads and they were 420 with the valve seal{450 total}. the valve seals are .100" tall
You need to measure them without the springs first. a general rule is a paperclip between the ratainer and the seal, and again the width of a paper clip with the springs on and cam at max lift.

I was in the same boat as you, with a head swap,I bit the bullet and had the machine work done. If you have to wait ,its worth it.

This is from Sallee Chevrolet's site.....

"Max. Valve Lift: 0.420” which allows 0.030” retainer-to-seal"

When I get the heads in I'll check them myself and reply as to what I find.

Vortec heads have a large diameter valve guide boss. You cannot put a Z-28 type spring on it without removing the innner damper. There are drop in springs for these heads made by comp and probably others, but are pretty pricey. Your best bet is to disassemble the heads and have the boss machined down in height to eliminate the possiblity of retainer to seal interference, and also have the diameter reduced so you can use a simple Z-28 type spring and retain the factory damper.

http://www.chevyhiperformance.com/h...7458/index.html

every thing you need to know about vortec heads
there real good info on value clearance

Just machine the guide down and get a much better spring kit from Competiton Products- the whole kit and the machining will cost you less than $125 total for improved vavletrain stability, better vavles easls, and no worries. Seems like a Benny well spent.

This thread is 4 years old.

Thanks for pointing that out, I almost responded.......anyways, I wonder if he had any problems

Respond anyway, people are still buying and using Vortec heads everyday.

What I recommend with Vortecs on a street motor is to cut the valve guide diameter down to take a 0.530" seal. Then the Z28 springs with damper will fit. You can buy the tools to do this yourself for less than 50 bucks. It takes a guide cutter and arbor. Then, you're set up to do subsequent heads for others and get your money back for the tooling.

Scoggin Dickey sells the springs, retainers and keepers under part number SD1004, good to 0.525" lift. It's $66.98 in my last year's catalog. Maybe a little more by now.
www.sdparts.com

I'm one of the guys using Vortec heads. I did all the machining myself. I believe the stock retainer to seal clearance was around .520-.530. I machined them to accept a cam with .550 lift (I have around .630 clearance). These are the 906 factory castings. I had a set of good springs laying around so I put them to use. I kept the dampers in them so it was necessary to machine the base of the guide boss to accommodate the damper. Seat pressure is 115-125lbs and the installed height is 1.725".

These heads sit on a Chevy 350 with a hydraulic flat tappet that is too big in my opinion. I have a lazy Erson grind (292/292 230/230 .480/.512....1.6 rockers on exhaust). The bottom end is essentially stock with .040 over cheap Federal Mogul hyper pistons. Compression is 10.45:1 (running 93 octane). On top is a PP dual plane air gap intake with a modified Holley 700 DP sitting on a 2" open spacer.

Here's the kicker. The engine is in my 1650lb dragster. I run 6.0's @ 110MPH in the 1/8 mile. It has gone 9.75 @ 133MPH in the 1/4 in some crappy air.

In a properly setup 3500lb car, I wouldn't see why low 12s couldn't be had with this combo. If the price is right, and your skills are average, these heads can really wake up a 350 at a price that won't kill the bank account.

I agree Digger. Best value there is in a cylinder head.

They are a great factory head but the aftermarket prices are coming down and the quality is going up- closing the gap.

That is true. But if you can score a set of Vortecs for dirt cheap (mine were $50) and you have some skills and tools, you can make a cost effective head. When machine work has to be farmed out, a new set ready to run (whatever brand it is) will probably be the better choice and will outperform the factory Vortec (not always, but most times).