Vortec Engine swap

[Hardcore]

I've been looking at rebuilding the bottom end on the 350 in my 1990 K5 and slapping on some vortec heads and Edlebrock TBI/vortec intake. Pricing out rebuilding my old motor and the nickel and dime stuff like new head bolts, gaskets, pushrods, etc is looking real expensive. For the cost of just the vortec heads I can get a complete low mileage vortec 350 out of the junkyard.
So my question; will there be any difference between the putting in a complete vortec 350 with the edlebrock intake and my TBI vs my old TBI block with Vortec parts? I assume the bottom end is all the same as far as motor mounts, flywheel, etc.

 

[dyeager535]

Yes there will be a difference, compression will be the big one. Nothing else really changed on the Vortec motors compared to prior small blocks mechanically except the injection setup and the heads.

The cost is going to start adding up if you haven't noticed, chip burning (required if you want it to run right) alone is going to set you back probably $200 or more.

 

[beater_k20]

So my question; will there be any difference between the putting in a complete vortec 350 with the edlebrock intake and my TBI vs my old TBI block with Vortec parts? I assume the bottom end is all the same as far as motor mounts, flywheel, etc.

yes, there will be a major difference. the roller cam... its a much better cam than the stock TBI cam, its already suited to run with the L31 engine combo, on top of being roller. otherwise, no, not much different really, everything will bolt up with the right intake.

do you have to pass emissions? if not, scrap the Edelbrock TBI intake idea and run a regular Vortec dual plane (for a carb) and an adapter. you're going to have to have a chip burned anyways, just have them disable the EGR functions and you'll be good to go. you wont have to make any mods to your exhaust if you go this route either (L31 heads require exhaust be plumbed from the exhaust manifold/header to the intake for EGR operation, L31 heads dont have the exhaust crossover that earlier heads do.)

 

[beater_k20]

Yes there will be a difference, compression will be the big one.

9:1 on the TBI vs. 9.6:1 on the Vortec, with chip tuning you're going to have to do anyways, this really doesnt matter. L31s will run just fine on cheap gas.

Nothing else really changed on the Vortec motors compared to prior small blocks mechanically except the injection setup and the heads.

the shortblock actually all of carries the same part numbers, with the exception of the pistons.

 

[JpEater]

Not all Vortecs have a roller cam. I have replaced 3 without the roller cam but have one in my garage waiting on a home that has a roller cam. Either way the cam wont matter. The most important thing will be the intake. As for the chip I know two people that have done the same swap and are more than pleased as is with no aftermarket chip.

 

[beater_k20]

Not all Vortecs have a roller cam. I have replaced 3 without the roller cam but have one in my garage waiting on a home that has a roller cam. Either way the cam wont matter. The most important thing will be the intake. As for the chip I know two people that have done the same swap and are more than pleased as is with no aftermarket chip.

yes, ALL L31s have roller cams. lets see some pics of your Vortec motor without the roller cams.

 

[JpEater]

yes, ALL L31s have roller cams. lets see some pics of your Vortec motor without the roller cams.

I am not trying to start crap here. I have replaced one 97' 350 and two 98' 350's without roller cams. I would say those are Vortec's: at least that is what the intake silencer said on it. Don't know about the L31 stuff though. There was obviously two different engines that were put in them though L31 and L??.

 

[beater_k20]

I am not trying to start crap here. I have replaced one 97' 350 and two 98' 350's without roller cams. I would say those are Vortec's: at least that is what the intake silencer said on it. Don't know about the L31 stuff though. There was obviously two different engines that were put in them though L31 and L??.

there was only one 'Vortec' 5.7 for '96+, that was the L31.


FWIW, my Vortec came out of a '96 Suburban produced late '95 (early November IIRC) so if in fact flat tappet cams were used in Vortecs, that'd be about the best chance you'd have getting one. mine is definitely roller.

i've got the entire parts breakdown around here somewhere in a notebook, with every GM Part number for both a '95 5.7 (L05?) , and the '96-99 L31. flat tappets are not even listed in the GM parts listing for the L31.

why i have this information you might ask? its slow at the dealerships in the middle of winter. i was bored in '02 and needed something to do.

 

[JpEater]

there was only one 'Vortec' 5.7 for '96+, that was the L31.


FWIW, my Vortec came out of a '96 Suburban produced late '95 (early November IIRC) so if in fact flat tappet cams were used in Vortecs, that'd be about the best chance you'd have getting one. mine is definitely roller.

i've got the entire parts breakdown around here somewhere in a notebook, with every GM Part number for both a '95 5.7 (L05?) , and the '96-99 L31. flat tappets are not even listed in the GM parts listing for the L31.

why i have this information you might ask? its slow at the dealerships in the middle of winter. i was bored in '02 and needed something to do.

I do know what I have seen. But back to the original topic good luck with the swap.

 

[sled_dog]

there was only one 'Vortec' 5.7 for '96+, that was the L31.


FWIW, my Vortec came out of a '96 Suburban produced late '95 (early November IIRC) so if in fact flat tappet cams were used in Vortecs, that'd be about the best chance you'd have getting one. mine is definitely roller.

i've got the entire parts breakdown around here somewhere in a notebook, with every GM Part number for both a '95 5.7 (L05?) , and the '96-99 L31. flat tappets are not even listed in the GM parts listing for the L31.

why i have this information you might ask? its slow at the dealerships in the middle of winter. i was bored in '02 and needed something to do.

what about the 305s? I've never seen a Vortec 305 apart. Are they flat tappet? I agree, 5.7L Vortecs were all Roller.

 

[beater_k20]

good question, however we are talking L31s, so i assumed that we were all on the same page. maybe not.

 

[Hardcore]

Good info guys. My local parts place has Vortec 350s (L31s) for a 96 chevy at a good price with a warranty. Makes it not worth the trouble going to the junkyard. Sounds like other that the vortec/TBI intake its a dirrect swap. Correct?