I searched for days. Please help (carb conversion)
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Joined: Jun 2010
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I searched for days. Please help (carb conversion) 
I know you guys probably answer these questions over and over but I have read these forums over and over and Im not finding these answers.
1. in doing an LT1 carb conversion and running an HEI distributor, do you have to switch the cam out to a regular SBC cam?
2. Now, if you dont have to switch cams, you can still use the stock water pump?
3. What modifications to a regular SBC intake need to be done to run one?
4. What mods need to happen on a vortec style intake?
5. Do vortech valve covers fit the LT1 heads?
6. Will a th350 bolt directly to an LT1 or will the bell housing need to be modified?
7. Is there any pulley systems out that replace the stock accessories setup?
I am putting a 383 LT1 (brand damn new) in a 1971 C-10 pickup.
I really want to chrome it out like you can with the SBCs but GMPP doesnt offer a shiny intake.
Also, I think it would look crappy with the stock pulley setup but I want to keep the air conditioning.
Thanks for your site and your help.
1. in doing an LT1 carb conversion and running an HEI distributor, do you have to switch the cam out to a regular SBC cam?
no, the LT1 cam is essentially the same, just a longer dowel pin for the opti.
My LT1 383 is carbed w/ HEI, and i run the comp cams XFI 292 LT1 specific cam.
2. Now, if you dont have to switch cams, you can still use the stock water pump?
yes, as long you use the LT1 timing set with the water pump gear drive teeth on it, if you switch to another type of regular SBC chain then an electri water pump becomes mandatory.
3. What modifications to a regular SBC intake need to be done to run one?
GM makes a "Dual Plane" carbed intake for the LT1, anytihng other then that and you need to: redrill some holes, get the correct angle on the holes, or use angled washers.
4. What mods need to happen on a vortec style intake?
same as above^^
5. Do vortech valve covers fit the LT1 heads?
as long as they are centerbolt valve covers yes.
6. Will a th350 bolt directly to an LT1 or will the bell housing need to be modified?
bolt right on in! thats whats behind mine!
7. Is there any pulley systems out that replace the stock accessories setup?
yes, "march pulleys" has some but they are expensive, "street & performance" has some very nice ones, but very expensive, there are a few more.
just remember, the LT1 is pretty much a regular sbc, just has reverse cooling, different intake bolt pattern. different water pump and accessories.
but any gen 1 SBC, cam,internals, timing chain (mods may need to be done to your cover depending on chain) ect ect.
heres my build, good info, check it.
https://ls1tech.com/forums/lt1-lt4-m...d-tonight.html
no, the LT1 cam is essentially the same, just a longer dowel pin for the opti.
My LT1 383 is carbed w/ HEI, and i run the comp cams XFI 292 LT1 specific cam.
2. Now, if you dont have to switch cams, you can still use the stock water pump?
yes, as long you use the LT1 timing set with the water pump gear drive teeth on it, if you switch to another type of regular SBC chain then an electri water pump becomes mandatory.
3. What modifications to a regular SBC intake need to be done to run one?
GM makes a "Dual Plane" carbed intake for the LT1, anytihng other then that and you need to: redrill some holes, get the correct angle on the holes, or use angled washers.
4. What mods need to happen on a vortec style intake?
same as above^^
5. Do vortech valve covers fit the LT1 heads?
as long as they are centerbolt valve covers yes.
6. Will a th350 bolt directly to an LT1 or will the bell housing need to be modified?
bolt right on in! thats whats behind mine!
7. Is there any pulley systems out that replace the stock accessories setup?
yes, "march pulleys" has some but they are expensive, "street & performance" has some very nice ones, but very expensive, there are a few more.
just remember, the LT1 is pretty much a regular sbc, just has reverse cooling, different intake bolt pattern. different water pump and accessories.
but any gen 1 SBC, cam,internals, timing chain (mods may need to be done to your cover depending on chain) ect ect.
heres my build, good info, check it.
https://ls1tech.com/forums/lt1-lt4-m...d-tonight.html
Just put a gen 1 motor in it. Do not limit yourself to LT1 parts or having to convert stuff.
The sequential injection is a big part of what made the LT1 what it is. Without it you just have a gen 1 with limited parts selection.
The sequential injection is a big part of what made the LT1 what it is. Without it you just have a gen 1 with limited parts selection.
Here you go..
https://ls1tech.com/forums/lt1-lt4-m...l#post13167404
As for the th350 trans question..yes they do bolt right up..now converters on the other hand might not work and you may need to change the flex plate..converters come in 10.75 or 11.50 bolt patterns for the flex plate..lt1 flex plate are 10.75 so if you end up with a converter with a 11.50 then you will need to spend 60$ on a diff flex plate with a dual bolt pattern..i say dual so you never have to worry about that again.
https://ls1tech.com/forums/lt1-lt4-m...l#post13167404
As for the th350 trans question..yes they do bolt right up..now converters on the other hand might not work and you may need to change the flex plate..converters come in 10.75 or 11.50 bolt patterns for the flex plate..lt1 flex plate are 10.75 so if you end up with a converter with a 11.50 then you will need to spend 60$ on a diff flex plate with a dual bolt pattern..i say dual so you never have to worry about that again.
Staging Lane
Joined: Jul 2006
Posts: 93
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Even if you got the 383 LT1 for free, 96Capricemgr's advice would be worth heeding. You could sell the 383 to someone who 'needs' an LT1 and be able to afford/build a Gen I a LOT easier/cheaper/more POWAHH than what you're contemplating, especially considering it's a transplant into an earlier platform. Besides, there's all that bling out there for Gen Is.
OT here, but kudos to 96Capricemgr for your measured response, nicely done!
Cheers -- Gary
Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so. -- Douglas Adams
OT here, but kudos to 96Capricemgr for your measured response, nicely done!
Cheers -- Gary
Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so. -- Douglas Adams
Last edited by Z48LT-1; Jun 6, 2010 at 11:08 AM. Reason: Corrected reference.
i dont think it is..when it comes down to it..if he sales the lt1 383,he will be out months an time for either doing the sale or building a gen 1 motor.
then no matter what hes still going to need a carb an a ignition system on the new motor just like he needs to switch on his lt1.
the only main thing he would need to convert would be heads on a gen 2 motor if he wanted to use gen 1 heads..but he already probley has aluminum heads now so no need..while most gen 1 engines hes going to have to buy a set.
the intake conversion is really simple..you dont need to take out the front where the water pump inlet is on a gen 1..you can just make a cap for the water inlet hole..an leave it there..then just widen the bolt holes and trim up some angled spacers and your done.
the lt1 block is stronger then a gen 1 block also.
then no matter what hes still going to need a carb an a ignition system on the new motor just like he needs to switch on his lt1.
the only main thing he would need to convert would be heads on a gen 2 motor if he wanted to use gen 1 heads..but he already probley has aluminum heads now so no need..while most gen 1 engines hes going to have to buy a set.
the intake conversion is really simple..you dont need to take out the front where the water pump inlet is on a gen 1..you can just make a cap for the water inlet hole..an leave it there..then just widen the bolt holes and trim up some angled spacers and your done.
the lt1 block is stronger then a gen 1 block also.
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i dont think it is..when it comes down to it..if he sales the lt1 383,he will be out months an time for either doing the sale or building a gen 1 motor.
then no matter what hes still going to need a carb an a ignition system on the new motor just like he needs to switch on his lt1.
the only main thing he would need to convert would be heads on a gen 2 motor if he wanted to use gen 1 heads..but he already probley has aluminum heads now so no need..while most gen 1 engines hes going to have to buy a set.
the intake conversion is really simple..you dont need to take out the front where the water pump inlet is on a gen 1..you can just make a cap for the water inlet hole..an leave it there..then just widen the bolt holes and trim up some angled spacers and your done.
the lt1 block is stronger then a gen 1 block also.
then no matter what hes still going to need a carb an a ignition system on the new motor just like he needs to switch on his lt1.
the only main thing he would need to convert would be heads on a gen 2 motor if he wanted to use gen 1 heads..but he already probley has aluminum heads now so no need..while most gen 1 engines hes going to have to buy a set.
the intake conversion is really simple..you dont need to take out the front where the water pump inlet is on a gen 1..you can just make a cap for the water inlet hole..an leave it there..then just widen the bolt holes and trim up some angled spacers and your done.
the lt1 block is stronger then a gen 1 block also.
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Brett Foote
On The Tree
Joined: Feb 2007
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I think this is a very viable alternative. From the factory, these are much better performance engines stock for stock. I might suggest Scoggin Dickey Performance though if you want a bit cheaper intake. I was on their website the other night, and their intake is 258 verses 289 what Jegs and Summit are currently selling for. Just an FYI on prices I found.
Thread Starter
Registered User
Joined: Jun 2010
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Thanks for all the advice.
I am thinking about selling the 383. It has a Callies 383 Stroker kit in it. ($2K kit)
I cant decide though. I'm not really ready to do the swap anyways. I still have all the body work to do.
I would much rather use a SBC but we'll see.
I am thinking about selling the 383. It has a Callies 383 Stroker kit in it. ($2K kit)
I cant decide though. I'm not really ready to do the swap anyways. I still have all the body work to do.
I would much rather use a SBC but we'll see.
Teching In
Joined: Feb 2009
Posts: 8
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From: McHenry, Il
Need some help Guys,
Heres my LT-1 conversion. I need some help timing this pig. I did the roller rockers to zero lash and then 3/4 turn. I started at TDC and timed it old school moving the distributor back and forth but i just can't get it to time right.
Am i missing something?
Thanks for the help.
thats what im actually doing to mine right now lol. keep turning it clockwise very little by little. move it a little, drive it. repeat till it get better lol or get a digital timing light and set it by that.
