I have heard that the chevy vortec heads have a max lift of .475 on each side (correct me if im misinformed). I was just wondering what would need to be done to run a bigger cam under it? And since Im rebuilding my engine for the 3rd time, i was hoping to get some advice on geting my rings to seat... The last two times they havent sealed and i would burn oil like a qt. every 100 miles. How long should it take, mileage wise? Also, can anyone tell me a good brand of piston to get? I was hoping for some of the hypertuenic type which will give me 10-10.5 to 1 CR. any thoughts would be awesome.

On a different note, Does anyone know of a website like this for hondas??? You guys have been super helpful when i needed to find out what was wrong with my car, and now i have a honda so I was hoping to find its equivalent... thanks

 

Hi. I'm a professional automotive machinist, and here's my 2 cents worth.
As for the heads, I myself have run just over .500 lift on unmachined vortecs just by changing springs/retainers/locks. But it's best to cut down the guides a bit. SD sells these heads this way for a lot extra, or you could take your heads to your local automotive machine shop. However, I've had plenty of these on a new, freshly-calibrated SuperFlow 1020 flowbench, and there's good reason to not exceed .480" lift on the intake side. The exhaust ports really need help.
As to your rings not seating, spending a bit more for moly rings will help, and you need to let your machinist know what rings you want him to hone for.
Most vortecs actually cc at 62 cc, not 64, so a flat-top piston, plus getting your piston-to-head clearance to 0.035-0.045" will give you about 10.4:1 on a 0.030"-overbored 350. For a 383, look for a 12 cc dish, such as from Speed
Pro or Keith Black. Good luck with your project.

 

Hey thanks that was really helpful. I heard the moly rings dont seat as well as the standard ones? Is there any truth in that? Just wondering.

Also, would you happen to know the stock bore diam. and rod length of a pre-86 350? Those seem to be the defining measurements when picking out pistons.

One more thing, Does honing really take away enough material to need to be accounted for with the rings?

 

4.00" bore
3.48" stroke
5.70' rod

You need a piston with 1.5XX compression height (CH ) for stock 350 configuration

 

I routinely hone 350s for customers 0.001" over what's called for, and have never had even one problem from it. If you go like 0.004" over, you'll get some piston slap, and it's not good. At that point, get another block or bore it to the next oversize. My experience with moly rings is that they seat faster. Plasma-moly rings seem to depend on the brand, but entry-level, single-moly rings, like for you a SpeedPro E251K, should be fine to 450 HP/6500 rpm, without any power adder.

 

I used a Crane 10309 spring/retainer kit on my stock Vortec heads to run the ZZ4 cam. With this kit you can run up to .550 lift (depending on whether or not you shim the springs to adjust seat pressure) without machining.