Yep, I'm going to the Dark Side. I came across a set of 062 Vortec heads, something like 38k miles, apparently something got into one of the cylinders and banged against the flat part of the head - minor dings, didn't touch the valves.

I'm thinking do the basic port/bowl clean-up (they don't need much), chamber and exhaust port polishing, valve guide narrowing, screw-in studs, cut valve guides & spring pockets, new springs, new rockers (haven't decided yet whether to go SA or guideplates). Not sure but will probably use the stock valves.

Put them on Berlinetta #1 with a spreadbore intake (limits choices a little, no Performer RPM spreadbore Vortec available, for example), and, you know, see what happens. . .

 

Sweet. I've read some posts of spring options that allow you to go above 0.5 on lift without any head work for the vortecs that would be a less expensive option than cutting the heads. I've been meaning to follow up on it but haven't had the time.

When you compare the size of the runners on the Vortec Performer to the regular Performer you won't feel as disappointed. They're taller to match the heads and I wouldn't expect as much of a diff between the VP/VPRPM as there is between the standard P/RPM.

I've got a second set of 062s in the garage that I couldn't pass up on last Fall. They'll probably go in my TA to replace the LG4 with a mild 350 next Winter. Will be a roller, maybe a LT1 type stockish cam-keep the mileage up.

 

kid, I've done literally dozens of these when I had access to a new SuperFlow 1020 flowbench, I promise, you don't want to touch the intake bowls or ports. Just get new 1.94" stainless swirl-polished valves with undercut stems and a 30 degree back-cut. That's it, the intakes are done. On the exhaust side, have them cut for 1.60" valves, 45 degree seats, with a 5 angle valve job including a 75 degree bowl hog, set to cut as deep as possible, until the 60 degree cut is the same width as the 45 degree cut. Then LIGHTLY blend the 75 degree cut into the ports. Do taper the exhaust guides, then lightly remove that ridge across the exhaust port "floor" (as installed in the engine), then completely polish all the exhaust ports. Again, use swirl-polished, undercut valves with a 30 degree back cut. I can get you flow numbers Monday.

 

Atilla

I also have a set of bone stock Vortec heads which I thinking of using on 350 or possibly 383 build. Which springs would you use for up to 0.525 lift (about 100 mills over stock Vortec's). I have seen some reports of people using LS1 springs - comments.

//RF

 

i have a complete 350 longblock vortec engine out of a 98 truck with the 062's on it. i have also heard about the ls1 springs. i have also been looking at the vortec heads that patriot performance sells that accept both late and early model intakes and valve covers.

 

It is possible to use that much lift, especially on the exhaust side, but on the intake side, I will only use COMP's Xtreme 4x4 hydraulic roller lobes, which are all ground for .474" lift w/ 1.50:1 rockers, because the vortec intake ports stall around 0.475", aln more lift, the flow is less. For up to .515 lift, you could just use competitionproducts.com 98111 springs, but past that I'd say beehives. Comp makes the 26981 (not 26918) just for SBCs to .525"

 

Monday I'll also list all the .474" hyd. roller lobes, including advertised duration at .006", duration at .050", and duration at .200"

 

i think i might take those specs you listed to a head shop when i find the right one and see if they can do them.

 

oh yay. are those specs good for a 1.6 roller rocker also????

 

if your cam gives you .474" with 1.50:1 rockers, 1.60:1 would lift the valves .506", which is not good with Vortec intake ports.

 

attila - i will be waiting for those - thanks for all that work.

 

here is a link to the 355 build that i am going to go after. not sure what the specs would be on the lift with the 1.6.

 

Here are the flowbench results I promised. These numbers will be a little lower than what the magazines post because this bench was brand new, fully electronic, freshly calibrated, and 4300 feet above sea level. All tests were at an ambient temp of 74 degrees, humidity was not checked. And I used a radius for the intakes, but no length of header pipe for the exhaust.
so,

 

intake: .100" went from 63 stock to 65 as I specified earlier, .200" 121 to 133, .300" 177 to 188, .400" 217 to 223, .475" 238 to 238. Still a good mid-lift improvement just from changing valves. The exhaust side shows much better improvement. .100" 46 to 57, .200" 98 to 114, .300" 132 to 149, .400" 140 to 167, .500" 143 to 177, .600" ??? to 181.
For Comp hyd. roller lobes, listed at .474" lift, here's the offerings:
lobe 3310: 252/200/122 duration. lobe 3324: 259/210/131. 3326: 263/214/134. 3303: 265/216/136. 3306: 269/220/138. 3307: 273/224/141. 3308: 279/230/145. 3309: 283/234/148. As compared to comp's best HF lobes, : 5085: 262/218/131 w/ .473", and 5443: 268/224/137 w/ .477". For those wanting hyd. non-roller with less duration, here are 2 good offerings for use with 1.6:1 rocker arms: 5082: 252/208/121, which with 1.6:1 gives .477", and 5441: 256/212/124, and again, 1.6:1 gives .477". There really aren't any good lobes for use as intake lobes with Vortec heads and 1.6:1 rockers, so if you want Vortec heads and hyd. roller lifters, stick with 1.5:1 rockers on the intake side.

 

Personally I'm just sticking with the ZZ4 cam and 1.5:1 rockers.

Do you have p/n's for the valves you're talking about? Manley Pro Flow, perhaps?

Are you saying to not even "air foil" the guides in the intake ports? Not looking to improve flow per se, just reduce turbulence a little.

 

The valves I use are sold by www.competitionproducts.com in sets of 16 for $80, then you hafta get a local shop to do the 30 degree back cuts. As for grinding the guides, I've tried doing only that, with the valves I recommended, and found absolutely no improvement. It makes sense to do it, that's why I did, but the SuperFlow says don't bother. The ZZ4 cam is an excellent match, be sure you verify your retainer-to-seal clearance. If you want affordable springs that can handle the .510" exhaust lift of the ZZ4 cam, I suggest the 98111 from competitionproducts. I've bought them for my ZZ4 cam, and had good results from them so far.

 

An update:

Took the heads to the engine man. He liked the idea. He cut the exhaust seats and bowl hog job, gave them back to me for the clean-up work I'm going to do. Although no problems are anticipated, he thought it wise to let me do my thing in case something turned out to be too thin. I ordered and received the valves from CP (had a deal going on where they threw in a set of valve seals). When I give him the heads back he's going to cut the guides for the seals, pop out the pull-out rocker studs and put in screw-in, and finish the valve prep and assembly. He has springs that will do the job (same thing I'm using on the Worlds now).

It'll probably be next month before all this gets done. I'm waffling on the spreadbore due to the limitation on intake choices, I do have a Holley 4779 I can put on an RPM manifold.

 

I know you're in love with the computer QJet, and I don't see why since it seems inferior to TBI, but there are aftermarket 4-barrel TBI setups you can put on an RPM AirGap. Alternately it would be possible to run an Accel SuperRam.

 

The CC q-jet is a very adaptable system. I didn't make any changes from the tuning made to the stock 305 to the hopped-up 305 to the current 350. Can't say that about any speed density system.

Besides, I don't have any TBI hardware. I'd have to go pick it up, adapt/install it in the car, upgrade pieces (like injectors, TB), do PROM tuning (for which I have no equipment), etc.

I also have all of the non-CC carb hardware needed except the Vortec intake manifold. I'll probably have to mod an air cleaner to clear the Holley float adjustment nuts or get an open element (might even have one of those stashed somewhere). Much easier and less hassle and expense than going to find a TBI system, or buying a stand-alone aftermarket EFI system.

 

hmmmm....... okay, that's all valid. Still, better driveability and mileage and engine life with a computer adjusting the fuel on the fly, as they say.

 

Did I mention the option of having the GM EGR dual-plane Extrude-Honed? That should get it close to a Performer RPM, but with the universal flange that accepts QJs

 

Yes, you mentioned extrude hone in a different thread.

The CC q-jet adjusts on the fly except under WOT, just like EFI.

 

Just like EFI, but slower (I got an autoxray last Summer)

 

but only the primaries, right?

 

Correct, which is why I said "except under WOT".

Carb still needs the venturi flow to draw the fuel in and vaporize it. EFI squirts the fuel into the air stream without aid of the air stream, and going from high to low pressure tends to vaporize the fuel more readily in the air stream.

I'm not saying CC carb is as good as EFI; what I am saying is the break-even point doesn't make it worth it to me to switch to EFI.

 

oh. okay, thanks.