What do I need to complete this swap?

[PlayingWithTBI]

FYI - This bored out 46mm Throttle Body flows 650 CFM which will support a 350 turning up to 6,000RPM. I'm running this with an 18LB spring set to 20LBs

https://www.ebay.com/itm/46mm-PORTE...837306?hash=item3d963196ba:g:mpwAAOSw2xRYWVJj

And these heads flow better than the Vortec ones.
https://www.summitracing.com/parts/sum-162108/make/chevrolet

 

[JayMB]

If you want to use your vortec heads you can use a manifold intended to put a carb onto a vortec engine (these can be found on some boats) and then get an adapter to put your TBI onto the carb flange. That'll be cheaper than the tbi-to-vortec GM piece. But won't support EGR (not sure if that matters where you live - probably not if you're thinking about slapping carbs on stuff).

 

[Lgarretto]

Those heads are nice. So is the bored out throttle body. But they are way too expensive. If I had the money for 1100 dollar heads I wouldn't be wasting my time with rusty old vortecs.
But the adapter may help. Thank you.

I am gunna probably price everything out before I continue much further. If I have to spend more than about 2000 I won't bother with it. I can toss in an lq4 with a cam and make more power for that much.

 

[Erik the Awful]

https://www.gmt400.com/threads/how-to-put-a-vortec-motor-in-a-tbi-truck.49463/
Lots of stuff I learned the hard way. Hopefully it helps.

 

[CrustyJunker]

If you can, look at your Vortec heads closely if they're used - many of them have cracks in them. Usually they are mostly asymptomatic on running engines aside of disappearing coolant. Not trying to scare you, but look carefully before you invest in valvetrain, etc.

 

[LC2NLS6]

As a stick truck, carb is the way to go for cheap. Get a cheap us cast manifold, brawler carb. Sell the engine you have as a core. Have the vortec torn down, cleaned up, dingle ball hone the cylinders if rust isn't too bad, reuse bearings if ok, slap it back together. Pull valve springs and check for rust in head runners/seats. Don't go crazy with cam since stock vrotecs can't take a lot of lift or spring.

 

[Lgarretto]

I did read that article. I am not going to be using the vortec block. I am going to use my 89 tbi block and just switch the cam and put the vortec heads on. Along with a vortec specific intake manifold of course. And I am going to keep the cam flat tappet. I'm not going to use a roller cam. I will use the rockers from the stock vortec heads. I was originally going to use a carb, but I've been told to stick with tbi. Looks like that is a cheaper option anyway since a carb will need the fuel pump modified or restricted and will need a different distributor as well. But I know nothing about tbi so I've been trying to learn that before I actually buy the parts

 

[Dravec]

Curious as to why you're sticking flat tappet. From what I've always read, and in my (very) limited experience, roller is worth between 5 and 10 degrees of cam. TBI block should have the bosses for the spider, at minimum. I've seen several that were already drilled and tapped from factory.
And I definitely second avoiding a carb. I may love my Quadra-puke, but even TBI is superior. And crazy reliable. No need to tune it every year.

 

[Erik the Awful]

I did read that article. I am not going to be using the vortec block. I am going to use my 89 tbi block and just switch the cam and put the vortec heads on.

I'm running a TBI(?) block with Vortec heads, and that thread was written with experience learned from exactly where you're heading.

It's definitely not a given that a TBI block has the roller cam bosses, but if your block has 'em, do it. Junkyard roller cam stuff is just too dirt cheap to not do it. Sure, I went flat-tappet in the spare engine I'm building right now, but it didn't have the roller cam bosses.

Vortec heads absolutely can take lift, if you use LS2/LS6 valvesprings and Comp Cams retainers. No machining required. Personally, if I'm rebuilding an engine, I want to replace the valvesprings anyways, because if a valvespring fails the valve can kiss the piston. The TBI is going to be your limiting factor. I don't have the tools to reprogram the ECU, so I went with a Holley Sniper with my .515" lift cam. Still having fits with getting it running smooth - might be an 02 sensor problem.

 

[realnorton]

If you want to use your vortec heads you can use a manifold intended to put a carb onto a vortec engine (these can be found on some boats) and then get an adapter to put your TBI onto the carb flange. That'll be cheaper than the tbi-to-vortec GM piece. But won't support EGR (not sure if that matters where you live - probably not if you're thinking about slapping carbs on stuff).