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GM Vortec Heads on an Early 350.


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 My son is buying  72 Chevelle from a friend of mine. (I have a 71 myself.) It's been in storage a number of years and needs a lot of work. The 350 in there is pretty shot and needs replacement or an overhaul. Standard Chevelle with an automatic, floor shift and bucket seats. 10 bolt rear with probably 2.73 gears. 

I've heard of people running late model Vortec heads on a small block. Seems they have good flow for stock. I have a 4 bolt main 350 out of a Chevy truck and have access to a pair of heads, There are intake manifolds available for carburetors with these heads. Anyone attempted or running this? I'm thinking bore the block .030 and put in flat top pistons. Dual plane intake like an Edelbrock Performer and 600 or 650 carb. 268 or 270 range cam, find some 3.55 or 3.73 gears and maybe a little looser converter. Do these heads require different headers? I've heard both ways. The chambers are pretty small so with flat tops the compression is probably 10 to 1 or so.  I also have another set of 186 casting 1970 GM heads which is what I'm using on my car. 

Maybe should detune my engine and put it in his car and build myself a better one. ?

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I haven't done this swap myself but looked into it about 10-12 years ago.  Edelbrock offered an intake for them (I'd think they probably still do.) I think GM Performance did at one time too.

Seem to recall stock Vortecs were prone to crack and required spring upgrades.  After pricing out a bunch of different heads I ended up going with aluminum AFR Eliminators.  I'm running a roller cam in a 383.

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They were probably some of the best flowing heads for the 350’s, truck heads were the best, like 94-98 Iirc, I would get them checked for cracks before you do any work on them, great head but have limitations, rocker studs were pressed in, recommend pulling them and tapping the hole for screw in studs, Cut valve guide protruding height down for cams above certain lifts, and you could go bigger valves, this all starts to add up, depends on what your wanting to do, flat tops will give you close to 10:1 and they have a intake manifold bolt pattern and the bolts go straight down instead of angle in, don’t recall any problems with headers

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Brother in law just dealt with heads on his 98 chevy. Water pump went out and got really hot. There are two vortec heads. Pickups/Suburban's with the factory tow package have a heavier duty heads. They don't flow quite as well as the std vortec heads but are less prone to cracking.

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Fwiw

I know they make manifolds.  Virtec heads are good.  And by the time you make them a little better with screw in studs etc you can just buy a brand new pair of GM performance or AFR etc etc for less than 200 more.  Now if they are free and just need machining...   I cant at test to the needing screw in with a sub .500 cam though.  Or under 7000rpm.  Maybe just slap them on with that performer rpm package and it will never fail.  Simple smart.

More pics please.  Looks like fun dad son project

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They work well, I have a vortec headed 350 in my 1980 Buick Electra, its a TBI 350 short block (stock roller lifters), Edelbrock roller cam and Edelbrock intake, pretty much what they sell as a '602" crate for circle track racing.  They have 64cc combustion chambers, which is there biggest claim to fame and the reason they make power, they have the exact same exhaust manifold pattern as every SBC, The claims of cracking on these and any newer "lightweight" SBC cylinder heads seems to be more common on the internet then in reality, they do have a lot less cast in them than a camel hump head, but I have only seen failure in a derby application being run at very high heat, possibly some of the extremely overheated (due to lack of coolant) vortecs that I have replaced in trucks have had cracks, but the entire engine was replaced, I wouldn't be opposed to just slapping an old set of heads on if they check out, or pulling a running engine and throw an intake and cam at it, an oil pressure switch to run a rattle can fuel pump and your set!  Also the bolt pattern in the ends of the heads has a different pattern than older heads, may have to do some accessory bracket modification, the pattern is different on either end of head as well, so some mocking up before assembly can make life easier, there is a specific intake gasket to use when installing the carb intake, the original intake had a plastic/rubber gasket, it is easy to find because of there circle track use

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I remember in Car Craft & Hot Rod magazines the Vortec heads were the hot item for budget built SBC. There's lots of options available for manifolds etc.

That said, if I was building a car these days, my money would be going into a LS. 5.3's are a dime a dozen and are just a few bolt-ons away from 400hp.

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Just put my 350 back together for my boat. Rebuilt a truck 350 years ago, small chamber heads, put domed pistons in it, mild cam, full rebuild, after a year of running one of the studs stripped and it bent a valve. Pulled the motor, sat in shop for years, had head rebuilt, except they didn't replace the stud, soooo I ordered the screw in upgrades, my experience.  If your studs are pinned as some were from the factory, "don't do it" !!!  While tapping the hole, it cracked The head. I now have a very expensive boat anchor. The small chamber heads were great for compression, but not so good for flow. Get some small chamber aluminum heads and be done. Get way better flow, standard gaskets, nothing special

IMG_20210629_144910702.jpg

IMG_20210701_155225214_HDR.jpg

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3 hours ago, TroyDairy said:

Fwiw

I know they make manifolds.  Virtec heads are good.  And by the time you make them a little better with screw in studs etc you can just buy a brand new pair of GM performance or AFR etc etc for less than 200 more.  Now if they are free and just need machining...   I cant at test to the needing screw in with a sub .500 cam though.  Or under 7000rpm.  Maybe just slap them on with that performer rpm package and it will never fail.  Simple smart.

More pics please.  Looks like fun dad son project

This was where I was at when I built mine.....for a few hundred more I got new aluminum heads.  At the time the AFRs were considered excellent heads.  Haven't kept up with the hot rod crowd anymore so I don't know what is on the market now.

I think the GM Performance Fastburn head is more or less an aluminum Vortec head.  No clue on pricing or if it is even available anymore.

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The screw in studs are a must with any kind of performance cam and springs.

I taped them with the head on the motor but you need to have the manifolds off to vacuum the chips out.

In the end you are much better off just buy an aftermarket aluminum head the HP gains with them out ways the hassle of reworking the stock style cast iron heads.

The LS swap would be the way to go they make good power stock and with add on's make 500+ easily 

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How old is your son? Nice car! Hard to imagine a car with sub 3:xx gearing being very impressive. I agree with you that gearset change would be a must. What are the carrier breaks on those rear end? 

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It really depends what he wants to do, his setup was spot on for an Ok street engine, I found myself entertaining this a couple months ago as I have an old 96 4x4 with the heads as a donor and was going to try a similar combo but the engine has dished pistons and you need around 10:1 for this to start working, then i would be breaking my old rule and starting to go down the small block road when big block is so much better on all fronts except fuel economy 

Definately going to need some gear to do anything, old wrench told us when we were teens we always started at the wrong end hot rodding, could go fairly aggressive back there and use a non electronic 700R4 to get the rpms back down for highway driving 

I not a techy but the LS platform is attractive, always tuned out of a toolbox not a laptop, their numbers are impressive 

Had a 70 Malibu I bought with 31,000 original miles never should have sold it, the one that got away...

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10 hours ago, vtfireman85 said:

How old is your son? Nice car! Hard to imagine a car with sub 3:xx gearing being very impressive. I agree with you that gearset change would be a must. What are the carrier breaks on those rear end? 

He's 20. I let him drive mine a few weeks ago and when this one came along he was very interested. The 72 has an open differential so needs replaced anyway, I'm not sure if it has an 8.2 or 8.5" ring gear. I had a 72 El Camino years ago that had a 8.2" 10 bolt with 2.73 limited slip rear end. I found a 12 bolt axle out of a 69 Chevelle with 3.31 gears that I put in it and then went to 3.90. That same rear axle is in my 71 now with 4.10 gears currently. I had my car on a chassis dyno and it showed 330 HP at the rear wheels which converted to just over 400 flywheel HP. About 9.5 to 1 355 so not too bad.

This 72 he's buying has been in my same town since new, I know the original owner who got it new. Funny thing is when the current owner bought it maybe 30 or so years ago I rebuilt the transmission for him. 

 https://www.jegs.com/i/JEGS/555/62808/10002/-1

 

https://www.jegs.com/i/JEGS/555/62804/10002/-1

https://www.summitracing.com/parts/sum-730962/make/chevrolet/model/chevelle/year/1972

https://www.jegs.com/i/JEGS/555/62806K/10002/-1

 

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21 hours ago, td9inidaho said:

Just put my 350 back together for my boat. Rebuilt a truck 350 years ago, small chamber heads, put domed pistons in it, mild cam, full rebuild, after a year of running one of the studs stripped and it bent a valve. Pulled the motor, sat in shop for years, had head rebuilt, except they didn't replace the stud, soooo I ordered the screw in upgrades, my experience.  If your studs are pinned as some were from the factory, "don't do it" !!!  While tapping the hole, it cracked The head. I now have a very expensive boat anchor. The small chamber heads were great for compression, but not so good for flow. Get some small chamber aluminum heads and be done. Get way better flow, standard gaskets, nothing special

IMG_20210629_144910702.jpg

IMG_20210701_155225214_HDR.jpg

Is that a bayliner?  

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11 hours ago, vtfireman85 said:

How old is your son? Nice car! Hard to imagine a car with sub 3:xx gearing being very impressive. I agree with you that gearset change would be a must. What are the carrier breaks on those rear end? 

Good point   But a ancient told me "brute tq makes up for leverage "  ?

Some of the ls turbo 10.5 tire cars ive seen are running quite high gears.  3.08, 3.23 and even seen a guy claiming 2.73 welded up dif.  All crazy fast.  Big turbo and little tire.  Want less giddie up and more go fast.  The higher gear let them leave gentler but at the 60 ft the turbo and fuel came in and boom they went.  Diff mindset to achieve same goal.  A empty wallet

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Fun with gears if I may take it OT for a bit.

So, I had a '40 Ford with a SBC. Rear end was Chevy. Pinion bearing went out so I was lamenting that I was walking until I could fix it. A friend said "I've got a chuck you can use, I'll drop it by" and he did! I looked at the tiny pinion and asked him what they were. With a smile he said 5.38s! It was locked with square spiders and I promptly snapped an axle so learned no popping the clutch - didn't need to. I had great fun with those for a couple of weeks, driving the streets of Boston and making square corners with a blip of the throttle! I loved to watch peoples faces. They were totally impractical and a locked rear is dangerous. Even with the compression I was running I could pretty much cruise around in 3rd/4th most of the time.

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23 hours ago, td9inidaho said:

studs are pinned

So my 327 (+.060) pulled a stud. Started running like crap with a heck of a clatter and I figured it was a bent push rod but no. I put an oversized stud and drilled and pinned them all. A couple of months later, same thing, except a stud broke at the pin. Machine shop got it out and screwed a stud in but it leaked coolant from the pin hole. Pipe dope held it and I sold the car for way cheap shortly after. Seems I met a girl and my priorities changed.

Thanks for flashing me back 50 years!

Edited by New Englander
.060, not .60
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When I had my heads ported and bigger valves put in they machined the boss where the studs went and went to hex head screw in studs and guide plates. Dual valve springs were needed with this cam,  and I run stud girdles on it. Rarely set the valves. 

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"I not a techy but the LS platform is attractive, always tuned out of a toolbox not a laptop "

 

There are intake manifolds and simple ignition "boxes" that allow you to run a carb and fire the coil packs. So, for the most part, you can set up a toolbox tunable LS. 

 

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My brother is big believer in LS swaps. 5.3/6.0. 

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I didn’t bring up the LS thing because best powertrain choice was not the original question, the LS is better, in every way but the bolt in factor, many different ways to attack that swap, old transmission and carb is the easiest, fuel injected and modern transmission the best, I’m a big carb guy but my cammed 02 Silverado 4.8L and my hp tuner is pretty awesome, tons of adjustments in tuning without getting dirty or leaving the seat, makes power and still fuel efficient too

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