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Jegs ATK Vortec 350

General engine tech -- Drag Racing to Circle Track

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Jegs ATK Vortec 350

Post by BOOT » Sat Dec 14, 2019 6:08 pm

Ok So I bought this crate engine off ebay and the more I go into it I'm not liking what I see. I mean I'm not an engine builder or machinist, maybe I'm being too picky but....





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Re: Jegs ATK Vortec 350

Post by rebelyell » Sat Dec 14, 2019 6:25 pm

For a few hundred $ more ... all Brand New 4-bolt Vortec crate
https://www.ebay.com/itm/GM-OEM-NEW-CRA ... SwTC1dUc2L

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Re: Jegs ATK Vortec 350

Post by BOOT » Sat Dec 14, 2019 6:37 pm

The Best new GM crate vortec I found at the time I bought this was bout $1950+tax. I did use a promo code so I saved bout $450-500 vs the GM. Still now I'm thinking it's not worth the savings.
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Re: Jegs ATK Vortec 350

Post by Monza355 » Sun Dec 15, 2019 1:23 pm

Interesting for sure. Aside from the markings on the bottom end and the rusty rods it looks OK. But the rusty rods are not acceptable in my book and from the looks of everything else in the bottom end they have been ugly during assembly!

If the cylinders and the lifter valley would have been fogged during the storage it would probably look better, like you mentioned.

It’s even 4 bolt mains instead of the listed 2 bolt. So that’s a plus for someone. But you probably just got lucky on that one :)

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Re: Jegs ATK Vortec 350

Post by rebelyell » Sun Dec 15, 2019 1:33 pm

Several months ago, the fleabay New crate seller (Radley Chevy Fredericksburg VA) had 'em for about $1850 ... dramatic increases since.

Like most factory reman motors, your atk is likely bored at least 0.030" if not 0.040" ... likely has plain generic 350 pistons (not the later Vortec type with desirable thin ringpack).

Decades back, I got a reman mazda rotary 12A from atk ... it's apex seals didn't last near as long as the OE motor's.

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Re: Jegs ATK Vortec 350

Post by BOOT » Sun Dec 15, 2019 7:16 pm

Monza355 wrote:
Sun Dec 15, 2019 1:23 pm
Interesting for sure. Aside from the markings on the bottom end and the rusty rods it looks OK. But the rusty rods are not acceptable in my book and from the looks of everything else in the bottom end they have been ugly during assembly!

If the cylinders and the lifter valley would have been fogged during the storage it would probably look better, like you mentioned.

It’s even 4 bolt mains instead of the listed 2 bolt. So that’s a plus for someone. But you probably just got lucky on that one :)
Yah once I saw the numbers didn't match the firing order and crusty rods I got kinda bummed out, they didn't rust that bad in the time it sat in my garage. Like you said only luck so far is 4 bolt, cause the ad says 2, almost made a caption but figured I'd bring it up in part 4, hard to get all the details when the camera is on.
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Re: Jegs ATK Vortec 350

Post by BOOT » Sun Dec 15, 2019 7:17 pm

rebelyell wrote:
Sun Dec 15, 2019 1:33 pm
Several months ago, the fleabay New crate seller (Radley Chevy Fredericksburg VA) had 'em for about $1850 ... dramatic increases since.

Like most factory reman motors, your atk is likely bored at least 0.030" if not 0.040" ... likely has plain generic 350 pistons (not the later Vortec type with desirable thin ringpack).

Decades back, I got a reman mazda rotary 12A from atk ... it's apex seals didn't last near as long as the OE motor's.
It's on my list to measure the rings, hope they are thin but prob not just like you said.
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Re: Jegs ATK Vortec 350

Post by BOOT » Sun Dec 15, 2019 7:24 pm

The rods rust/order are really what bugs me, the other little things here n there are interesting but meh. At this point since I did buy it on ebay I'm considering trying to get a return or something, they are pretty good bout any issues.
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Re: Jegs ATK Vortec 350

Post by rebelyell » Sun Dec 15, 2019 8:11 pm

You've already disassembled motor. Without sellers prior permission; right?
I'd like for you to get a do-over, but I wouldn't count on a return.
Unless you find a gross misrepresentation or poor work (corroborated by a pro), you might just as well proceed as it'll probably be ok; just not such a good value.

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Re: Jegs ATK Vortec 350

Post by BOOT » Sun Dec 15, 2019 8:51 pm

rebelyell wrote:
Sun Dec 15, 2019 8:11 pm
You've already disassembled motor. Without sellers prior permission; right?
I'd like for you to get a do-over, but I wouldn't count on a return.
Unless you find a gross misrepresentation or poor work (corroborated by a pro), you might just as well proceed as it'll probably be ok; just not such a good value.
Great point! Still I think it's perfectly reasonable someone might remove the oil pan to change it.
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Re: Jegs ATK Vortec 350

Post by BOOT » Thu Mar 19, 2020 3:25 pm

Part 4

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Re: Jegs ATK Vortec 350

Post by rebelyell » Thu Mar 19, 2020 8:34 pm

Nowadays w/ cheap valves being even cheaper, the cheapest way to fix worn out guides is simply ream them for OS valves and that's what you got for ATK. FYI the head without the ex insert has a hardened seat; Induction hardened same way GM has done for decades. If worried about valve mass; have shop install liners to fit LS/8mm stems.

Suggest fix whatever is truly wrong w/ atk bottom, don't port vortecs except for LIGHT cleanup; install some good seals & cheap springs (Z28 minus dampers) and cam to make .500 - .525 lift and it'll likely make about 400 reliable HP . Get it into your C3. Suggest put the camera down & focus on the job; then execute.

And please, suggest don't subject us to video in order to elicit a response.

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Re: Jegs ATK Vortec 350

Post by BOOT » Thu Mar 19, 2020 9:03 pm

I wouldn't put more $ into these heads for even 11/32 liners as I said in the vid, nor 8mm not that there is anything wrong with that. Thought the deal with vortecs was the HD trucks had a exh seat insert and it left a ridge that hurt flow. Still I'm no head or vortec expert.

Check out my vortec basic port video if you wanna see what I'm gonna do to them port wise. I prefer LS beehive springs and comp retainers. C3 already has a shortlbock in it with a .450 cam

You can suggest all day but I enjoy making vids as much as I do modding parts so GL with that LOL If you don't wanna watch don't click on em! Even better just put me on the foe list for speedtalk and you won't see my post! Thx for your feedback :)
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Re: Jegs ATK Vortec 350

Post by ProPower engines » Thu Mar 19, 2020 10:07 pm

I feel for ya it is painful to see thats for sure. But reality is the rebuilding of an engine in todays high volume shops
that is really what you see. Deck heights all over the place. Most likely because of a crank they saved and off set ground a journal to save it.
The thicker head gaskets drive me nuts as well. the stock gasket is .028 compressed why use a .045 thick gasket?
They get them in bulk like the other gaskets.\
the head thing with 2 different numbers is just wrong to have 1 head with hard seats and 1 without.
The pitting on the cam well its a re-grind that happens and while it looks bad on the base circle it may never cause any issues but it goes to show what they want to save to keep em cheap. The timing set is just a cheapo silent set good for about 30K till it needs changing again.

But after its All said and done you really got a $1995.00 engine. The only difference between the ATK and a from GM engine
is there may not be any rust inside.Or will there.

Its cost that drives this market and buyers look at the dealer cost and other options and this is the end result.
The parts they used may be fine their tolerance level is the same as the factory from all those I have dealt with.

Hope it works out for you :D
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Re: Jegs ATK Vortec 350

Post by SupStk » Thu Mar 19, 2020 10:14 pm

Just do a google search on ATK on read the feedback. It companies like that who keep me in business.
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