Someone just told me this, is it true?

[superj]

If you change the intake a vortec v8 then it is rhe same as any other sbc? I thought the heads and cam where different also

 

[Daly]

The Vortec is a SBC. Are they the same as any other SBC? No. Every generation of SBC from the first till the last are based off the same general idea and design, but there are deferences in every variation. Simply swapping the intake doesn't make it the same as another SBC. Vortec is the head design on that generation of SBC... Most SBC parts are interchangeable...

 

[Justin S]

Ive seen many people take the older small blocks and put vortec heads on

 

[michael hurd]

It would be best to post what you want to do.

Old intake manifolds do not share the same port configuration and bolt pattern. They have vertical bolts and raised intake ports.

You can use a 96+ vortec 5.0 / 5.7L in an old vehicle with a carburetor and a stand alone large cap HEI ignition if you so desire.

You will need to change the distributor drive gear to be compatible with the steel roller camshaft that Vortec engines come with. The GM gear for roller cam applications is a 'melonized' gear.

As far as a fuel pump goes, you will have to use an electric fuel pump of an appropriate pressure for a carburetor, or a return style regulator set up.

Exhaust port flange is the same as older small block bolt patterns.

5.7L Vortec heads flow light years better than any older head out of the box, even better than the as delivered un ported bowtie race head, but are prone to cracking.

5.0 vortec head castings are not the same as 5.7 vortec heads.

Vortec heads can be modified to work with higher lift camshafts, but the stock valve spring / retainer / lock set up will crash the retainers on the top of the valve seal / valve guide at between 0.460-0.480" lift - depending on plant of manufacture, production tolerances and valve depth.

2500 and 3500 L31 cylinder heads from what I have read have Inconel valve seats and a single angle valve job, in order to combat the high exhaust temperatures from high load / pulling applications.

L31 C/K 1500 heads do not.

 

[superj]

My buddy wants to swap his 4.3 for a 5.0 or 5.7 but all w can find are vortec engines. He is not interested in tons of wiring mods to get the engine to run so he wants to try to find a regular tbi engine since his is a tbi truck.

We hit the junkyards and all the ads on craigslist with no luck. Everything is vortec. So we are wondering can he get a tbi intake from someone line edelbrock and drop the vortec in and it run like a tbi engine?

 

[michael hurd]

Swapping a 4.3 TBI for another is easy, however swapping from a V6 to V8 is more complicated. Literally everything is different.

If doing this on the cheap, you will need an ecm from a similar truck equipped with the correct engine size (5.0 or 5.7), the same transmission as the one in your friend's truck, type of drive ( 2wd or 4wd ) and the same gear ratio.

Without doing that, you are destined for fail.

Yes, you can swap a different intake onto a Vortec to accept a TBI unit with properly sized injectors, and bumped up fuel pressure at the regulator. You also need the correct ecm, or at least a prom from a V8. ( someone correct me if I am wrong )

The roller cam and better flowing heads are going to require more fuel.

I am not certain of the 4.3 TBI injector flow rating ( # per hour @ XX psi ) but they are a different part number than the 5.0L, which is also a different part number than the 5.7.

You can not take your 4.3 TBI and jam it on a V8 with a random intake and expect it to run.

 

[superj]

i guess he is going to try and do this as cheaply as possible. i told him just pull the head on the passenger side of hte 4.3 and get it checked and redo the head gasket and his truck will be back to fine but he wants to do a v8 since he already has to put the truck down to get it running properly

 

[livelifewideopen]

edelbrock makes a carb intake that bolts to vortex heads. then you need to get an adapter for a carb intake to a TBI intake which they make as well. then you need an ECU out of a TBI v8 (which then needs a chip installed for your set-up, TBIChips.com is a great source for custom chips), an upgraded fuel pump, and an adjustable fuel pressure regulator in the throttle body. Or you can run the carb intake for vortex heads, and rip all the old computers out of the truck, and pick up an easy Tunable EFi system Like you would run when swapping over a carbed engine, but the second option should be the more expensive route.

 

[michael hurd]

Or, you could fix the V6 and drive it. Put the couple of grand that you would throw towards putting a V8 in the truck and save up for a newer truck.

 

[Justin S]

I did A 6 to an 8 swap and I loved having the v8 over the 6. Much better sound!