LT1 swap carbed please help.
03-11-2017, 06:09 PM
#1
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Join Date: Nov 2014
Posts: 4
LT1 swap carbed please help.
Needing some info, im from the uk and getting parts here is a knightmare and also very expensive, which is why i have to work with what i have.
I have a 1984 z28 with a carbed 350 sbc in it, with terrible smog heads that u have been trying to replace. but cant get any decent vortecs or otherwise over here.
I have been given an LT1 from a 1997 camaro, and im hoping to replace my SBC with it. I cant get the pcm or wiring so was hoping to carb it with what i have.
hoping you guys can point me in the right direction.
1. I dont have aircon in my car so am i right in saying if i get rid of the aircon compressor on the LT1 it will fit straight in? im also running a th350 will it mount straight up to this with the old SBC flex plate?
2: if i get a different intake manifold can i just fit my edelbrook carb and msd distributor?
3:can i use the exhuast manifolds from my SBC?
4: Can i leave the optispark there and will the waterpump on the LT1 plumb up to my radiator etc.
5; can i bolt my harmonic balancer to the LT1 and if so how do i reference the timing.
6: can i fit my sbc power steering pump and alternator to the LT1.
7: i need an electric pump or is there a provision to fit fit the manual pump from the SBC.
Thankyou for your time, i know it would be alot easier to keep the fuel injection etc but its just not possible to get the parts here.
I have a 1984 z28 with a carbed 350 sbc in it, with terrible smog heads that u have been trying to replace. but cant get any decent vortecs or otherwise over here.
I have been given an LT1 from a 1997 camaro, and im hoping to replace my SBC with it. I cant get the pcm or wiring so was hoping to carb it with what i have.
hoping you guys can point me in the right direction.
1. I dont have aircon in my car so am i right in saying if i get rid of the aircon compressor on the LT1 it will fit straight in? im also running a th350 will it mount straight up to this with the old SBC flex plate?
2: if i get a different intake manifold can i just fit my edelbrook carb and msd distributor?
3:can i use the exhuast manifolds from my SBC?
4: Can i leave the optispark there and will the waterpump on the LT1 plumb up to my radiator etc.
5; can i bolt my harmonic balancer to the LT1 and if so how do i reference the timing.
6: can i fit my sbc power steering pump and alternator to the LT1.
7: i need an electric pump or is there a provision to fit fit the manual pump from the SBC.
Thankyou for your time, i know it would be alot easier to keep the fuel injection etc but its just not possible to get the parts here.
Last edited by draven666; 03-11-2017 at 06:16 PM.
03-11-2017, 08:47 PM
#2
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
re: LT1 swap carbed please help.
1: A/C see below w/ reference to "delete idler pulley". Not sure about the TH350. Why do you want to keep a non-overdrive trans? A 700R4 / 4L60 would be a lot more street friendly. I run a TH400 and couldn't live with the high RPM at freeway speed, so I added a Gear Vendors overdrive unit). Is your current Gen 1 SBC a 1-piece or 2-piece rear main seal? That may affect the choice of flexplate. The LT1 is a 1-piece RMS. And the flexplate has the balance weight required to balance the LT1 engine. The damper on the LT1 is simply a torsional damper, neutral balanced.
2: The LT1 heads have a different bolt pattern for the intake manifold. GMPP (GM Performance Products) makes a dual-plane 4 BBL intake manifold for the LT1. Includes a hole for a Chevy small block distributor. If you want to use a Gen 1 SBC (pre-LT1) intake on the LT1 heads, you will need to have the two center holes on each side of the manifold relocated, old holes filled. The make angled shims to place under all the bolt heads because the angle of the bolts is different on the LT1.
3: The LT1 heads have D-port exhaust ports. Might have a problem getting Gen 1 ports to seal on the D-port shape.
4: GMPP sells a blanking plate for the Opti cavity. Otherwise you can leave the Opti there, but it's just another potential source for an oil leak. And eventually the bearing is going to fail.
The LT1 has a unique "reverse flow" cooling system. Here's the flow diagram:
http://shbox.com/1/95-97_hoses.jpg
5: You need to use the LT1 damper. It has a 3-arm hub that is unique. The LT1 crank hub is not keyed to the crank. The crank has a keyway, but the hub does not. You will need to have a keyway cut in the hub. Then you would have to mark the degrees on the damper. Alternatively, buy an ATI Super Damper - hub is correctly keyed and perimeter of damper is marked 360-degrees. You have to fabricate a pointer.
6: Might be able to adapt the alternator, but not likely the PS pump. The LT1 PS pump has a remote reservoir. Does the LT1 not have the accessories included? Does it have the stock front accessory bracket? If so, seems like getting an LT1 pump, LT1 alternator, an LT1 A/C delete idler pulley, keeping the LT1 damper and running the serpentine belt would be a lot easier.
7: Assuming you mean fuel pump, you need an electric pump. There is no provision for a traditional mechanical pump on the LT1 block.
I'm going to post this, and proof-read it in the morning, on my PC. iPad is not as friendly for editing.
2: The LT1 heads have a different bolt pattern for the intake manifold. GMPP (GM Performance Products) makes a dual-plane 4 BBL intake manifold for the LT1. Includes a hole for a Chevy small block distributor. If you want to use a Gen 1 SBC (pre-LT1) intake on the LT1 heads, you will need to have the two center holes on each side of the manifold relocated, old holes filled. The make angled shims to place under all the bolt heads because the angle of the bolts is different on the LT1.
3: The LT1 heads have D-port exhaust ports. Might have a problem getting Gen 1 ports to seal on the D-port shape.
4: GMPP sells a blanking plate for the Opti cavity. Otherwise you can leave the Opti there, but it's just another potential source for an oil leak. And eventually the bearing is going to fail.
The LT1 has a unique "reverse flow" cooling system. Here's the flow diagram:
http://shbox.com/1/95-97_hoses.jpg
5: You need to use the LT1 damper. It has a 3-arm hub that is unique. The LT1 crank hub is not keyed to the crank. The crank has a keyway, but the hub does not. You will need to have a keyway cut in the hub. Then you would have to mark the degrees on the damper. Alternatively, buy an ATI Super Damper - hub is correctly keyed and perimeter of damper is marked 360-degrees. You have to fabricate a pointer.
6: Might be able to adapt the alternator, but not likely the PS pump. The LT1 PS pump has a remote reservoir. Does the LT1 not have the accessories included? Does it have the stock front accessory bracket? If so, seems like getting an LT1 pump, LT1 alternator, an LT1 A/C delete idler pulley, keeping the LT1 damper and running the serpentine belt would be a lot easier.
7: Assuming you mean fuel pump, you need an electric pump. There is no provision for a traditional mechanical pump on the LT1 block.
I'm going to post this, and proof-read it in the morning, on my PC. iPad is not as friendly for editing.
Last edited by Injuneer; 03-11-2017 at 08:49 PM.
03-12-2017, 06:29 AM
#3
Registered User
Thread Starter
Join Date: Nov 2014
Posts: 4
re: LT1 swap carbed please help.
1: A/C see below w/ reference to "delete idler pulley". Not sure about the TH350. Why do you want to keep a non-overdrive trans? A 700R4 / 4L60 would be a lot more street friendly. I run a TH400 and couldn't live with the high RPM at freeway speed, so I added a Gear Vendors overdrive unit). Is your current Gen 1 SBC a 1-piece or 2-piece rear main seal? That may affect the choice of flexplate. The LT1 is a 1-piece RMS. And the flexplate has the balance weight required to balance the LT1 engine. The damper on the LT1 is simply a torsional damper, neutral balanced.
2: The LT1 heads have a different bolt pattern for the intake manifold. GMPP (GM Performance Products) makes a dual-plane 4 BBL intake manifold for the LT1. Includes a hole for a Chevy small block distributor. If you want to use a Gen 1 SBC (pre-LT1) intake on the LT1 heads, you will need to have the two center holes on each side of the manifold relocated, old holes filled. The make angled shims to place under all the bolt heads because the angle of the bolts is different on the LT1.
3: The LT1 heads have D-port exhaust ports. Might have a problem getting Gen 1 ports to seal on the D-port shape.
4: GMPP sells a blanking plate for the Opti cavity. Otherwise you can leave the Opti there, but it's just another potential source for an oil leak. And eventually the bearing is going to fail.
The LT1 has a unique "reverse flow" cooling system. Here's the flow diagram:
http://shbox.com/1/95-97_hoses.jpg
5: You need to use the LT1 damper. It has a 3-arm hub that is unique. The LT1 crank hub is not keyed to the crank. The crank has a keyway, but the hub does not. You will need to have a keyway cut in the hub. Then you would have to mark the degrees on the damper. Alternatively, buy an ATI Super Damper - hub is correctly keyed and perimeter of damper is marked 360-degrees. You have to fabricate a pointer.
6: Might be able to adapt the alternator, but not likely the PS pump. The LT1 PS pump has a remote reservoir. Does the LT1 not have the accessories included? Does it have the stock front accessory bracket? If so, seems like getting an LT1 pump, LT1 alternator, an LT1 A/C delete idler pulley, keeping the LT1 damper and running the serpentine belt would be a lot easier.
7: Assuming you mean fuel pump, you need an electric pump. There is no provision for a traditional mechanical pump on the LT1 block.
I'm going to post this, and proof-read it in the morning, on my PC. iPad is not as friendly for editing.
2: The LT1 heads have a different bolt pattern for the intake manifold. GMPP (GM Performance Products) makes a dual-plane 4 BBL intake manifold for the LT1. Includes a hole for a Chevy small block distributor. If you want to use a Gen 1 SBC (pre-LT1) intake on the LT1 heads, you will need to have the two center holes on each side of the manifold relocated, old holes filled. The make angled shims to place under all the bolt heads because the angle of the bolts is different on the LT1.
3: The LT1 heads have D-port exhaust ports. Might have a problem getting Gen 1 ports to seal on the D-port shape.
4: GMPP sells a blanking plate for the Opti cavity. Otherwise you can leave the Opti there, but it's just another potential source for an oil leak. And eventually the bearing is going to fail.
The LT1 has a unique "reverse flow" cooling system. Here's the flow diagram:
http://shbox.com/1/95-97_hoses.jpg
5: You need to use the LT1 damper. It has a 3-arm hub that is unique. The LT1 crank hub is not keyed to the crank. The crank has a keyway, but the hub does not. You will need to have a keyway cut in the hub. Then you would have to mark the degrees on the damper. Alternatively, buy an ATI Super Damper - hub is correctly keyed and perimeter of damper is marked 360-degrees. You have to fabricate a pointer.
6: Might be able to adapt the alternator, but not likely the PS pump. The LT1 PS pump has a remote reservoir. Does the LT1 not have the accessories included? Does it have the stock front accessory bracket? If so, seems like getting an LT1 pump, LT1 alternator, an LT1 A/C delete idler pulley, keeping the LT1 damper and running the serpentine belt would be a lot easier.
7: Assuming you mean fuel pump, you need an electric pump. There is no provision for a traditional mechanical pump on the LT1 block.
I'm going to post this, and proof-read it in the morning, on my PC. iPad is not as friendly for editing.
i should of said earlier that i was hoping to drill my intake but if not i know i will have to buy a new one.
so with the reverse waterflow following the diagram i should be able to use my existing radiator, extending pipes and plumbing correctly?
I get what your saying with the damper and crank hub set up, i havent collected the engine yet and assumed it wouldnt have accessories but hopefully it will.
will the lt1 accept my motor mounts or will i need the lt1 mounts?
03-12-2017, 04:47 PM
#4
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: LT1 swap carbed please help.
The back end of the crank should be the same if they are both 1-piece RMS. Next question is whether your flexplate has the correct balance weight on it for an LT1. The LT1 rotating assembly is lighter, due to the light weight hypereutectic pistons.
I don't know if connecting the LT1 pump to the earlier radiator will make any difference. Note also that there is a connection on the LT1 radiator for the coolant that the "steam tube" returns from the back of the heads. It's shown in the diagram, passes through the throttle body on the EFI LT1 (95-97 only), but you will will need a place to connect it. The connection on the LT1 radiator has a liquid/vapor separator on it. Others should be able to tell you where to connect it, because it's a fairly common question - just one that I have never had reason to address. You need to keep the steam tube, because that allows air and steam bubbles to escape from the back of the heads, reducing hot spots.
Don't know the answer to the motor mount question.
I don't know if connecting the LT1 pump to the earlier radiator will make any difference. Note also that there is a connection on the LT1 radiator for the coolant that the "steam tube" returns from the back of the heads. It's shown in the diagram, passes through the throttle body on the EFI LT1 (95-97 only), but you will will need a place to connect it. The connection on the LT1 radiator has a liquid/vapor separator on it. Others should be able to tell you where to connect it, because it's a fairly common question - just one that I have never had reason to address. You need to keep the steam tube, because that allows air and steam bubbles to escape from the back of the heads, reducing hot spots.
Don't know the answer to the motor mount question.
03-17-2017, 11:39 AM
#5
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Join Date: Jun 2003
Posts: 1,083
Re: LT1 swap carbed please help.
The GM Opti block off plate does have a timing pointer on it. I would get a ATI damper. Has 360 degree timing marks and is a keyed hub. Get the LT1 specific one for the body type & year of the donor LT1 (B,Y or F) accessory bracket. The hub depth is different between the 3 and on your 97 donor motor it is OBD2 with a crank position wheel so get the ATI for that 96 or 97 year. Hub depth is different from 94-95 years
The GM carb intake manifold would be the way to go vs drilling & filling the SBC manifold, IMHO.
It would be easier to use the alternator, power steering and water pump from the donor car with the LT1 accessory bracket.
As mentioned the LT1 is a reverse flow cooling (heads 1st then block) and uses a external from radiator reservoir that also has a hose to connect to the steam pipe specific to LT1 heads. On stock routing this hose connects to the throttle body and out the other side connects to steam pipe. You can bypass the throttle body and connect it direct to steam pipe and just use 3/8" rubber plugs to cap off TB in/out (or just leave open as it is just a seperate water passage in the TB body) You may likely need different shape/length radiator hoses to connect the LT 1 WP to your existing radiator
The GM carb intake manifold would be the way to go vs drilling & filling the SBC manifold, IMHO.
It would be easier to use the alternator, power steering and water pump from the donor car with the LT1 accessory bracket.
As mentioned the LT1 is a reverse flow cooling (heads 1st then block) and uses a external from radiator reservoir that also has a hose to connect to the steam pipe specific to LT1 heads. On stock routing this hose connects to the throttle body and out the other side connects to steam pipe. You can bypass the throttle body and connect it direct to steam pipe and just use 3/8" rubber plugs to cap off TB in/out (or just leave open as it is just a seperate water passage in the TB body) You may likely need different shape/length radiator hoses to connect the LT 1 WP to your existing radiator
Last edited by Chimera96; 03-17-2017 at 11:56 AM.
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