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#1011756 - 09/05/14 07:11 PM L31 vortec 350 engine swap details?  
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Chevy Runs Deep Offline
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Chevy Runs Deep  Offline
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Atlanta, Ga
Greetings everyone.
Just a few questions regarding swapping in an l31 long block that would be carbed. Questions about reusing v belt accessories, heater bypass, how the stock cam responds to a carb, header fitment on vortec exhaust ports, fuel system options whether in tank or inline. The motors seem to be pretty cheap and common, just small details to swap it in.
Thanks!
Bernard


1983 Chevy Monte Carlo...ss clone
...... In Progress ...... Vortec headed 350 hyd roller etc
2013 Chevy Silverado Z71....dd....TRADED
2005 Chevy Equinox....wife's dd
2015 Chevy Camaro SS....LS3 M6
#1011808 - 09/06/14 03:02 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
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87ChooChoo Offline
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87ChooChoo  Offline
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las Vegas, NV
Pretty much everything will swap over, except fuel pump. Distributor may need a Roller Cam gear ( melonized). In line Electric Pump will be OK for carb'd application. Keep it to 7 PSI or less ( may need regulator). No EGR capability in the heads, so if you need EGR, you will have to track down an EGR install kit. Special bolts available for the Vortec Intake Manifold ( designed to not crush the vortec gaskets. I would swap the heater bypass for one from a '96 truck. It allows the heads to get some flow while warming up. If going into your '83, you will need a different flexplate. Need a way to block off the crank sensor on the timing cover.


85 El Camino Choo Choo with L31 350 Crate, TPI, Serp, TES Headers, GN 200-4r, 3.73 8.5 GN Posi, Acura Buckets, '04 GP Console, Electric Mirrors, Electronic HVAC, ZQ8 wheels, Blazer front brakes, LS1 rear brakes, and more....
https://sites.google.com/site/darbyselky/home
#1011834 - 09/07/14 01:28 AM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Mar 2011
Posts: 32
Chevy Runs Deep Offline
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Chevy Runs Deep  Offline
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Joined: Mar 2011
Posts: 32
Atlanta, Ga
Thanks 87 Choo Choo. Yes going in the 83. So reuse all vbelt front end accessories. Use flexplate and starter from l31. Reuse th350. Reuse hooker longtubes. No emissions. Need vortec intake, gaskets, and bolts. Heater bypass from truck.

I would prefer an intank fuel pump for the carb rather than inline since it's a street car. Maybe someone can elaborate on their setup. I'm familiar with factory style repairs vs modifications. What's needed for an intank electric fuel system for a carb?
Am I missing anything?
Thanks.


1983 Chevy Monte Carlo...ss clone
...... In Progress ...... Vortec headed 350 hyd roller etc
2013 Chevy Silverado Z71....dd....TRADED
2005 Chevy Equinox....wife's dd
2015 Chevy Camaro SS....LS3 M6
#1011836 - 09/07/14 03:10 AM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
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Fred SS Offline
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Fred SS  Offline
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Glassboro, NJ
Is it possible Bernard could use a TBI fuel pump assembly and tank along with a fuel pressure regulator? The TBI pumps have less pressure than the typical fuel injection application but more than carbs. A regulator could possibly reduce it enough for the carb without having allot of fuel being routed back to the tank. This would be a more oem looking install. Comments?


87 SS, Harwood cowl induction hood, UMI trailing arms. Edelbrock TES Headers (Jet Hot Coated). Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, Bilsteins, TCI 2400 stall converter, Ramcharger fans, Denny's 3.5" Driveshaft, GBodyParts GNX Wheels.
#1011892 - 09/07/14 09:49 PM Re: L31 vortec 350 engine swap details? [Re: Fred SS]  
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87ChooChoo Offline
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87ChooChoo  Offline
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las Vegas, NV
Originally Posted By: Fred SS
Is it possible Bernard could use a TBI fuel pump assembly and tank along with a fuel pressure regulator? The TBI pumps have less pressure than the typical fuel injection application but more than carbs. A regulator could possibly reduce it enough for the carb without having allot of fuel being routed back to the tank. This would be a more oem looking install. Comments?


Should work fine. Locating a used one can be tricky, but new senders are available, as well as TPI pumps. Just need to regulate it down to 7psi from 15. If you keep the tanke 1/4 full or greater, no issues with starving the fuel pump. If you can find a TBI fuel tank it should have some baffles that will help with this issue, but not necessary.


85 El Camino Choo Choo with L31 350 Crate, TPI, Serp, TES Headers, GN 200-4r, 3.73 8.5 GN Posi, Acura Buckets, '04 GP Console, Electric Mirrors, Electronic HVAC, ZQ8 wheels, Blazer front brakes, LS1 rear brakes, and more....
https://sites.google.com/site/darbyselky/home
#1011966 - 09/08/14 09:50 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
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Chevy Runs Deep Offline
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Chevy Runs Deep  Offline
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Atlanta, Ga
Would a Buick Grand National sending unit work? Seems easier to find online than a 4.3 tbi sender. I suppose a tbi pump would be easier for the fuel pair regulator to work properly. Then somehow add a return line to the carbed tank. Anyone know what fittings, line, would be required for converting to basically an efi fuel setup but still using a carb... minus the baffled tank I wouldn't need as the fuel vowels should hold enough fuel to make it through a fast corner. Please excuse my rambling


1983 Chevy Monte Carlo...ss clone
...... In Progress ...... Vortec headed 350 hyd roller etc
2013 Chevy Silverado Z71....dd....TRADED
2005 Chevy Equinox....wife's dd
2015 Chevy Camaro SS....LS3 M6
#1011967 - 09/08/14 10:26 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Oct 2003
Posts: 1,479
87ChooChoo Offline
10+ Year
87ChooChoo  Offline
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Joined: Oct 2003
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las Vegas, NV
GN Sender will work fine. Same as the monte sender. Use a TBI pump, and you are golden. I used the "Vent" line as my return line, and then added a 5/16" fuel hose for the vent to the charcoal cannister. Some Montes had the return line as stock off the stock fuel pump- I think it just depends on the year.

I would change all of the rubber fuel line on the pressure side to FI capable fuel line- it won't take much- maybe 6' of 3/8" line. Buy a box of FI Hose clamps on Ebay. I double clamped all of mine, but I run a higher pressure. at 15 PSI, single clamps will be OK. Add an inline filter ( I used Fuel Filter G6332 Autozone ( FF4506)(G3870 ?). If you use the vent line for your return, be sure to put it onto the return port of the sender. The vent port at the sender has a restriction in it.


85 El Camino Choo Choo with L31 350 Crate, TPI, Serp, TES Headers, GN 200-4r, 3.73 8.5 GN Posi, Acura Buckets, '04 GP Console, Electric Mirrors, Electronic HVAC, ZQ8 wheels, Blazer front brakes, LS1 rear brakes, and more....
https://sites.google.com/site/darbyselky/home
#1011998 - 09/09/14 12:36 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Mar 2011
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Chevy Runs Deep Offline
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Chevy Runs Deep  Offline
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Atlanta, Ga
Short recap... Reuse feed line to fuel pressure regulator, return line from regulator back to sender if mounted near tank, fuel filter to feed line to carb. Or, feed line to engine compartment mounted regulator, reuse vent line back to sender. New vent line to charcoal canister. Will use fuel injecting hose to replace all old rubber fuel line.


1983 Chevy Monte Carlo...ss clone
...... In Progress ...... Vortec headed 350 hyd roller etc
2013 Chevy Silverado Z71....dd....TRADED
2005 Chevy Equinox....wife's dd
2015 Chevy Camaro SS....LS3 M6
#1012005 - 09/09/14 02:48 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Oct 2003
Posts: 1,479
87ChooChoo Offline
10+ Year
87ChooChoo  Offline
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Joined: Oct 2003
Posts: 1,479
las Vegas, NV
Originally Posted By: Chevy Runs Deep
Short recap... Reuse feed line to fuel pressure regulator, return line from regulator back to sender if mounted near tank, fuel filter to feed line to carb. Or, feed line to engine compartment mounted regulator, reuse vent line back to sender. New vent line to charcoal canister. Will use fuel injecting hose to replace all old rubber fuel line.


Sounds good. Mounting the regulator near the tank would be easy, but not convenient for adjusting pressures. Depending on your regulator, might consider a FP Gauge or a connection for one in the engine compartment, for adjujstment.


85 El Camino Choo Choo with L31 350 Crate, TPI, Serp, TES Headers, GN 200-4r, 3.73 8.5 GN Posi, Acura Buckets, '04 GP Console, Electric Mirrors, Electronic HVAC, ZQ8 wheels, Blazer front brakes, LS1 rear brakes, and more....
https://sites.google.com/site/darbyselky/home
#1012015 - 09/09/14 04:43 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Mar 2011
Posts: 32
Chevy Runs Deep Offline
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Chevy Runs Deep  Offline
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Joined: Mar 2011
Posts: 32
Atlanta, Ga
Thanks for the help 87 Choo Choo! I'll update the thread in a week or so with progress after a trip down to Summit Racing.


1983 Chevy Monte Carlo...ss clone
...... In Progress ...... Vortec headed 350 hyd roller etc
2013 Chevy Silverado Z71....dd....TRADED
2005 Chevy Equinox....wife's dd
2015 Chevy Camaro SS....LS3 M6
#1012233 - 09/12/14 01:31 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Oct 2000
Posts: 1,148
WaSSted Offline
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WaSSted  Offline
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Kennewick
Not sure what you mean I'm reguards to heater bypass so I'll reply anyway. I do know you will want a heater valve from a 97 pickup if you plan on using the heater, the original will not work. Otherwise bypass it with a hose, which I'm sure were your initial intentions.


Kirk Herres
86' SC/SS, 350 Vortec, Rpm intake & Cam, 750cfm Edlebrock Carb, 3" True Duals w/Flowmasters and DR. Gas X pipe, All Autometer Gauges, B&M Hammer Shifter, Accel wires & ign., and 3.73 Posi.
#1012238 - 09/12/14 03:50 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Mar 2011
Posts: 32
Chevy Runs Deep Offline
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Chevy Runs Deep  Offline
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Joined: Mar 2011
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Atlanta, Ga
WaSSted,
I've read somewhere about vortec engines needing external bypass or overheating can occur. HVAC components are all here but I don't plan on running them with this being a fair weather cruiser. Since you're running a vortec engine could you elaborate on your setup. Another question I had was if the serpentine drive from the truck would fit in the monte without the actual compressor and using a shorter belt. What did you do for fuel? Basically looking for a bare bones swap to get her running as im anticipating a move soon. Thanks for all the help.


1983 Chevy Monte Carlo...ss clone
...... In Progress ...... Vortec headed 350 hyd roller etc
2013 Chevy Silverado Z71....dd....TRADED
2005 Chevy Equinox....wife's dd
2015 Chevy Camaro SS....LS3 M6
#1012242 - 09/12/14 04:24 PM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
Joined: Oct 2003
Posts: 1,479
87ChooChoo Offline
10+ Year
87ChooChoo  Offline
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Member

Joined: Oct 2003
Posts: 1,479
las Vegas, NV
This is the Heater bypass valve for the Vortec engines. Allows some flow of water through the heads/intake before the thermostat opens up.

http://www.oreillyauto.com/site/c/detail/MRY0/74781/02708.oap?year=1997&make=Chevrolet&model=C1500%2BPickup%2BRWD&vi=1031555&ck=Search_02708_1031555_-1&pt=02708&ppt=C0331

You should be able to use the truck serpentine setup, but you would have to change the water pump, get an AC delete pulley, and possibly a different length belt.

I usually run 91, but I think you should be able to run on less- the compression is not that high. I've run 89 with no issue- haven't tried '87 yet, but the ECM should compensate for it anyway.


85 El Camino Choo Choo with L31 350 Crate, TPI, Serp, TES Headers, GN 200-4r, 3.73 8.5 GN Posi, Acura Buckets, '04 GP Console, Electric Mirrors, Electronic HVAC, ZQ8 wheels, Blazer front brakes, LS1 rear brakes, and more....
https://sites.google.com/site/darbyselky/home
#1012308 - 09/14/14 12:08 AM Re: L31 vortec 350 engine swap details? [Re: 87ChooChoo]  
Joined: Jan 2007
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rons87mcss Offline
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PA
FWIW, a stock L31 engine runs just fine on 87 octane. I never ran anything else in my 1998 Z71 when I had it with the ridiculous prices of fuel today.

#1012316 - 09/14/14 02:28 AM Re: L31 vortec 350 engine swap details? [Re: rons87mcss]  
Joined: Nov 2008
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jmireles Offline
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jmireles  Offline
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El Paso, Tx
Originally Posted By: rons87mcss
FWIW, a stock L31 engine runs just fine on 87 octane. I never ran anything else in my 1998 Z71 when I had it with the ridiculous prices of fuel today.


We used to have 87 octane...86 now. I noticed pinging on loads, so I used premium two weeks ago. Wow, quite a difference! I'm breaking about even now that fuel prices have come down. I love the acceleration and response on my '97 Z71. Not to mention I'm getting slightly better mileage.


-'87 Monte SS LS 2/4L65e Quick Perf. 9" w/disk brakes
-'89 Iroc Z28 Stock 5.7 Edelb. TES headers, Borla Exhaust90K
-'77 Trans Am 468(Stroked) Doug's Headers Flowmaster catback
B & M shift Kit 400 Turbo trans. Edel brock Performer
RPM Intake Sean Murphy built Rochester Carb. Restored
in '08. 3K
#1012548 - 09/17/14 04:52 AM Re: L31 vortec 350 engine swap details? [Re: Chevy Runs Deep]  
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WaSSted Offline
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WaSSted  Offline
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Kennewick
Coolant must always be flowing between the intake port and pump or engine will over heat. Just run a heater hose from the intake to the water pump and you will be fine. If you decide you want heat you need a two way control valve.
I'm using an edelbrock mech fuel pump.
From my research the pickup serp will hit the steering box. You need a setup from an f body or an s10.


Kirk Herres
86' SC/SS, 350 Vortec, Rpm intake & Cam, 750cfm Edlebrock Carb, 3" True Duals w/Flowmasters and DR. Gas X pipe, All Autometer Gauges, B&M Hammer Shifter, Accel wires & ign., and 3.73 Posi.

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