final prep for vortec head swap

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guitarfreak235

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Well I finally have the 350 running straight and decided to take the plunge and do a vortec head swap! ive done a ton of research and am excited to see the results. i have just a few questions as i prepare

The 350 is a 4 bolt main early-mid 70s ls9 code. came from a 75 but valve covers said 73. unsure if it was the original engine.

right now its stock cam'd with true dual exhaust/headers, and the 86 quadrajet.

I just bought a donor engine from a 97 1500. 5.7 vortec 906 castings.

For the intake manifold, I got an aluminum high rise, single plane manifold for cheap off craigslist. Its square bore and obviously the q-jet is spreadbore. In terms of adapters does anyone have experience with using an edelbrock 2693 offset adapter or something like it? the carb is offset slightly to the rear to help, supposedly, with mixture distribution on single plane, square manifolds fitted with spread bore carbs. I know its a long shot but just curious if anyone knows.

For clearance and access purposes, I have an edelbrock foam style breather. The triangular shaped one called pro-flo.


Lastly, my torque will probably be a bit much for the 700r4, even with the stock cam. This in addition to the fact that I dont haul anything, makes me want to be sure the trans is safe. I may want to get a new cam but do not want monster torque to blow the tranny.

Im looking for as much power as possible in the mid-upper range, while not over torquing the tranny, and not sacrificing drivability/cruising. Its my DD so I want it to be strong without sacrificing good cruising manners.
As of now, I have the stock 73~5 cam in. I was wondering if the engine would be better with the old cam, or the vortec cam.

Is the vortec cam flat tappet? can it be used in my motor?

With that being said, I am about ready to get this show on the road. It doesnt seem that we have a vortec head swap how-to, so I figured I would document the process and make a potential sticky for those who want to try it. Seems like plently of people ask about this.

:cheers:
 

bucket

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There's not much to it really, just have to keep less than .475 lift at the valve unless the heads have been cut for more lift. Then you also have to run the correct intake meant for use with Vortec heads.

A stock Vortec cam is a roller cam BTW.
 

bucket

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Oh, and self-aligning style rockers are needed too, along with centerbolt style valve covers. But both of those were put in use clear back in '87.
 

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Roller cam, roller lifters.
 

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Oh, and self-aligning style rockers are needed too, along with centerbolt style valve covers. But both of those were put in use clear back in '87.

yea ive done all my research, I can tell you all about vortec motors, 906 vs 062 castings blah blah blah. In terms of theory I am more than prepared for the swap, Its just my first time going deeper than the manifolds/headers and The only questions I have really concern the spacer/adapter for spreadbore to single plane squarebore manifolds and which cam to use...

having said that i just looked it up and found out about the rollers. at this point should i ditch the 350 short block and use the vortec block?

9.5 compression ratio compared to 9 on the vortec heads on the old school block plus the rollers....

ill double check to see if the vortec has mehanical fuel pump provisions...
 

bucket

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I've got a Vortec block out in the garage, I don't remember it having fuel pump provisions. I know I've had TBI blocks that didn't... the mounting boss was there, just no hole for the pushrod.
 

guitarfreak235

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I've got a Vortec block out in the garage, I don't remember it having fuel pump provisions. I know I've had TBI blocks that didn't... the mounting boss was there, just no hole for the pushrod.

read somewhere that some do, some dont. one way to find out, ill be back in the morning
 

guitarfreak235

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checked the engine and it does have fuel pump provisions. even the ones that did have them did not all have the hole for the pump rod so i checked that and everythings good.

the oil is also much cleaner than the 73 motors, so now im pretty sure ill just drop in the whole vortec.

i can just prep the vortec motor for now and do the swap when I have the time.

so now Im wondering, should i just stick with everything on the vortec as is, and only swap the intake to accept my carb? or should I keep the existing accesories on the truck for the swap?

lasty, what increments can I retard the stock cam, and how do I do so? I know you can turn it 1 tooth but dont know how much timing this would result in. I want to move the torque curve up slightly, partly for the sake of the transmission, partly for performance. i never tow anyway.
 

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Don't use the single plane intake , it's way too wrong for your setup. I bought my performer vortec for $60 + shipping off of Ebay, and that's what you need also !

Unless you have a degree wheel to set your cam timing with you'd be best to leave the cam be. If you want more mid-range & top-end then please just buy a new cam.
 

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the high rise single plain intake is a really bad choice for a street engine bud hunts the reason it was sold for cheap. look up the specs for it and ask yourself. do i plan to continuously drive in that rpm range like a circle track guy? the trans isn't add weak as it is make it to be. sure it could use a little tweak to beef it up, but unless your gonna beat on it it'll be ok. i see your young, so I figure you'll be doing plenty burn outs. word of advice burn outs on a slippery surface do less damage then smoke shows in the street. with the same wow factor.

Sent from the dust in front of you!
 

bucket

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Check the vortec cam to see if it has the lobe to push the fuel pump rod.

And you adjust cam timing with an adjustable timing set. There will be a keyway for a few degrees advanced, another keyway for retarded, and of course one for straight up. Going a full tooth is too far.
 

guitarfreak235

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Don't use the single plane intake , it's way too wrong for your setup. I bought my performer vortec for $60 + shipping off of Ebay, and that's what you need also !

Unless you have a degree wheel to set your cam timing with you'd be best to leave the cam be. If you want more mid-range & top-end then please just buy a new cam.

i realize its not good for it but I got it for 70 bucks... dang though 60 for a performer? I didnt care too much as i really have no use for monster torque anyway. I wont be off roading with this anymore or towing anything. Honestly I would prefer as much mid-upper performance as possible without bad cruising/drivability.

I plan on the cam swap anyway, thinking about something like the lt4 cam or even the hot lt4 but thatll require work on the heads. Just toying around with the idea of changing the cam timing just to see what it does. Just wondering if someone knows how much each tooth is offhand. Its more of just experimenting than anything
 

guitarfreak235

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the high rise single plain intake is a really bad choice for a street engine bud hunts the reason it was sold for cheap. look up the specs for it and ask yourself. do i plan to continuously drive in that rpm range like a circle track guy? the trans isn't add weak as it is make it to be. sure it could use a little tweak to beef it up, but unless your gonna beat on it it'll be ok. i see your young, so I figure you'll be doing plenty burn outs. word of advice burn outs on a slippery surface do less damage then smoke shows in the street. with the same wow factor.

Sent from the dust in front of you!

I know about the differences in intakes, but it was the cheapest I could find, plus like i said, dont need a ton of torque. it should be more than What I have now anyway right? correct me if Im wrong but wouldnt the single plane not be able to offset the gains in torque from the vortec?

The guy actually sold it because it wouldnt fit his NON VORTEC old school heads. (go figure)

lastly, I envision converting this truck to manual someday, i hate automatics. thatd help with drivability
 

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Hey it's your money bud. I'm just trying to help. .. just know idle and driving under 1500rpm will not be so good:( idle mainly.
anyhoo best off luck to ya bud.

Sent from the dust in front of you!
 

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