What do I need to complete this swap?

[Lgarretto]

Hi guys. I'm sure all this has been covered at one time or another. But I would like to put it up here incase I've chosen some dumb part that won't work or is gunna screw me. Also I apologize for the long post. I am gunna try to be thorough

So I have an 89 swb with a 350. And a stick. All stock. But the engine is burning a bit of oil (I think it's the valve guides) and I'd like to make a bit more power anyway.
So I bought a complete 1996 vortec 350 a few days ago. Has 150k on it. It's supposed to run but was already out of the truck. It looks good. I am looking at cleaning up this engine and putting it in my truck.
I am planning to swap to a carburetor instead of tbi and I'm going to put the chevy performance cam from the 330/380 vortec crate engine in it. I know I can swap to the beehive springs and use something like comps 268 cam and make more power for not much more money. But I don't have the funds to swap to a t56 or something right now that will actually hold that kinda power. Besides. This is my daily.
I can surface the heads (I am a machinist with access to cncs) but I am not an engine machinist and I don't have the facilities to bore and deck the block or anything. If that needs done I will take it somewhere but I'd like to get away with just surfacing the heads lightly.
As for a parts list, other than that cam and the vortec heads I am looking at a rebuild kit, maybe with pistons, from somewhere like summit or jegs. A mechanical fuel pump (I am not sure if that or regulating the one I have is the better option though). An intake manifold for a carb and of course the carb. Looking at one with a mech secondary that flows 600cfm. And an hei distributor. I happen to have a set of headers I found at a swap meet.

Again I apologize for the long post. Just wanted to toss this out to yall and see if I'm screwing myself or what. I appreciate any input you guys have for me. Thanks

 

[Schurkey]

The carb swap is a huge mistake. A true mechanical secondary (Holley or clone?) is a worse mistake; unless you mean a mechanical secondary controlled by an air valve like a Q-jet; which would still be a mistake--just not as bad. Reconsider.

Will your block accept an engine-driven fuel pump? Most Vortec blocks will not. Using the standard electric pump will require some re-wiring because the pump is supposed to be controlled by the ECM, and you won't be doing that with a carb-and-HEI distributor. The electric pump will have to be regulated down to 5--6--7 psi instead of the 17-ish it's capable of.

What water pump are you using? You will likely need to use a Vortec pump with the Vortec bypass, the block is probably not equipped for the older, TBI-and-previous bypass system. Some Vortec blocks do have the old style bypass holes drilled in them. They tend to be the same ones that have a fuel-pump provision, and generally have 4-bolt mains as well.

Verify the compression height (AND the compression RATIO, they're not the same thing) of any pistons you buy. Many common pistons are deliberately built "too short"; they cheat you out of compression pressure and they rob you of proper quench distance. Makes for a slow, lazy burn needing too much spark advance and leads to detonation. Ideally, you'd have at least .030 but not more than .045 quench distance. Expect to deck the block; and consider using a thinner-than-typical head gasket. Having the pistons at "zero deck" and then using a .040 head gasket is common; as is having the pistons .010 down in the bores, then using a .028 head gasket. These engines were designed for pistons .025 in the hole, and a .015--.020 head gasket; but that may not be feasible any more--steel shim head gaskets are LONG out of style, even if they're still available for some Chevys.

The last Vortec short-block I built, I had to cut the deck .025. If I'd been thinking clearer, I'd have cut the deck .015 and used a thinner head gasket.

 

[Lgarretto]

I was going to use a quick fuel brawler. I have used one before on a family members Pontiac. His is a 63 though. I have read that the tbi system won't support the power I would expect to be close to after the cam. Why is a carb swap a bad idea?

I will have to check on the fuel pump. I have read on how you can rewire the stock one with a regulator so I can do that if needed. I did not know the vortec blocks won't accommodate an engine driven pump.

I planned to use the stock water pump. Or an oe replacement. Since I'd either use the one I have or buy one for a vortec it should work no?

I will keep that in mind for pistons. I haven't removed the heads yet. I don't know what condition the stock ones are in. I would expect to need to hone the cylinders lightly and install new rings at least. I would like to get away with not having to replace lower end parts if I don't have to though.

I will have to check the cylinders. If they aren't too bad and I can just replace the rings would you still suggest decking the block and possibly using a thicker head gasket to compensate? Or just clean it and leave it? I will keep in mind that I need a. 03-.045 quench


Also, thank you

 

[Lgarretto]

Also I planned to use the vortec block and heads and keep my block in the truck in the meantime. If needed I can use the 89 block I have. Although I'd like the extra power the cam and vortec heads will give

 

[b454rat]

Use the TBI. I built a pretty healthy 406 with all 100% stock TBI system. I used the Comp Cams Exreme 268 with regular lifters, it had a sweet idle, and it pulled like a freight train on nitrous. For a driver i wouldn't worry bout the trans, I ran a stock 700 with that 406 lol...


Also, just tear the vortec apart to inspect it. No need to rebuild it if it doesn't need it. I have a 98 Tahoe with 203k on the clock and runs like it has 3k.

 

[Lgarretto]

OK so I can just use my tbi? I kept reading that it will only support like 260 horse. I'll need to get it tuned won't I?
Also if I keep the tbi would I be better off putting the vortec heads on my old block in place of the swirl port heads? Or using the entire vortec block? Assuming for arguments sake they are both in the same condition. Just which would be simpler?

 

[Schurkey]

Vortec will be roller-cam. TBI will have a flat-tappet cam, but MIGHT be roller-cam compatible.

When it was me, I used a Vortec short-block, then put aluminum aftermarket heads and intake on it, with the stock throttle body and distributor on top.

All on the stock PROM. Runs great except when cold. I think I need to jack the fuel pressure up.

 

[Lgarretto]

I believe I read somewhere that most blocks made after I think 87 have roller cam capabilities. OK. I'll just have to open it up at this point and see how much I overpaid for this engine haha. Thanks

 

[Schurkey]

I believe I read somewhere that most blocks made after I think 87 have roller cam capabilities. OK. I'll just have to open it up at this point and see how much I overpaid for this engine haha. Thanks

Most small-blocks new enough for a one-piece rear main seal also have roller-cam capacity. Not all, and the truck TBI may have a suitable block, but will be missing all the actual parts--the roller cam, the thrust plate, the special timing set, the roller lifters, the dogbones, spider, and the short pushrods.

Not having the short pushrods is no great loss if you're using heads that have pushrod guideplates, as the guideplates will destroy the OEM pushrods. But if you're using stock Vortec heads with the self-aligning rocker arms, the OEM pushrods could be entirely suitable.

 

[Lgarretto]

Well I pulled the heads last night. The block has been sitting maybe a bit longer than the guy said. It isn't locked, but it is dang tight. And the cylinders are a bit rusty. So I may get the heads cleaned and surfaced and just plop them onto my swirl port block. I found chevy part number 12496821 which is a manifold that fits vortec heads that will also fit the tbi. It's the only one I found. 550 bucks is expensive for a manifold. But if the tbi off my truck will support the power it's easier than swapping to a carb. If my block can use a roller cam I may look at how expensive that will be. Otherwise I can use a flat tappet.
Thank you guys