04 Vette LS1 swap into Grand Prix Accessory fitment?

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Shinobi68

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Mar 6, 2023
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I recently inherited by Grandfather's '85 Pontiac Grand Prix, I noticed while driving it how many people like it. Got some thumbs up, I'm used to getting thumbs up in my C8 (sold), Thirdgen's, and other cars, but am surprised at the amount of love these G Bodies get. I love driving and cruising the Grand Prix and have decided to make this somewhat of a daily driver. But I live in the foothills and the 3.8 is a dog climbing in and out of canyons and climbing hills...sure drives nice though on flat land, but not inspiring by any means. I have a rebuilt '69 327 SBC and TH350 sitting in the garage that would have been a much simpler swap, but after I spec'd out Trick Flow Heads, Cam, Oil Pump, EFI sniper and headers, the SBC ends up costing as much as the LS1 I just picked up with 50K miles on it.

The LS1 I have is a complete drop out from an 04 Vette, I have purchased most of the swap parts from Holley (motor/transmission mounts, pan, etc.), but have not pulled the trigger on the Radiator, Gas Tank/Pump, and Accessory Mid Mount kit. I am just wondering before I buy anything else, if anybody knows whether the Vette accessories will work without notching the frame for the low mount AC pump? I have read on this forum some stating that Vette accessories will work, and other stating they will not. I need to have AC in this car as summers get over 100* and the wife has to have AC...even know I told her she could always roll down the window. I want to take this car on some road trips as it's very comfortable and I suppose she will have to go too....so I need AC.

Thanks
 
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Streetbu

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I do not know if the Vette accessories will fit as is. Sorry. For what your doing the Holley drop in fuel module sounds perfect. 93-97 LT1 Camaro radiator and fans are a drop in using a Cutlass radiator plate. Sounds like you have the mounts all figured out. Good luck and keep us posted!
 
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Shinobi68

Not-quite-so-new-guy
Mar 6, 2023
21
13
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I do not know if the Vette accessories will fit as is. Sorry. For what your doing the Holley drop in fuel module sounds perfect. 93-97 LT1 Camaro radiator and fans are a drop in using a Cutlass radiator plate. Sounds like you have the mounts all figured out. Good luck and keep us posted!
Thanks for confirming the Holley Drop in fuel pump will work...looking at the 255lph pump with build in regulator. Great info on the 93-97 LT1 Camaro rad and fans fitting, however I'm wondering the LT1 is a reverse flow motor with respect to the coolant, are sure you don't mean LS1 Camaro rad? I wonder if the Cutlass rad plate is the same as the Grand Prix?
 

Streetbu

Know it all, that doesn't
Supporting Member
May 22, 2011
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Central NY
Thanks for confirming the Holley Drop in fuel pump will work...looking at the 255lph pump with build in regulator. Great info on the 93-97 LT1 Camaro rad and fans fitting, however I'm wondering the LT1 is a reverse flow motor with respect to the coolant, are sure you don't mean LS1 Camaro rad? I wonder if the Cutlass rad plate is the same as the Grand Prix?
Nope, I mean the LT1. The LS1 F body guys actually switch to the LT1 radiator because it bolts right in, and is thicker.
 
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Supercharged111

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Nope, I mean the LT1. The LS1 F body guys actually switch to the LT1 radiator because it bolts right in, and is thicker.

I think if you go to Napa it doesn't matter, but stock for stock yes this was 100% the case. An OP the coolant flow made no difference on the radiator construction, the LS shed heat more efficiently so GM decided to cheap out with an extra wimpy radiator for the LS cars.
 
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Texas82GP

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Apr 3, 2015
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Not sure if the low mount a/c compressor will clear without notching the frame. There are options to high mount a compressor on the passenger side with the rest of the Vette accessories. Holley makes brackets for both an R4 and Sanden compressors. If you go with an R4, the condenser and hose assembly from the early 90's Camaro with the high mount R4 on the passenger side fits well.
 
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Built6spdMCSS

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Jun 15, 2012
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I've always ran the LT1 Fbody Radiator in all my swaps. LT1 reverse flow was how the coolant went through the Engine, Radiator is the same.

I'd look into mounting the AC Compressor on the upper passengers side. Easy to get to if needed.
 
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Built6spdMCSS

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Here's some info on the radiators..

LS1 Fbody is 7/8" thick

LT1 Fbody is 1" thick

Both are pretty much identical, the LT1 Fbody Radiator has an extra port on the bottom driver's side you just cap off, not used with the LS Engine. I've used the LT1 Radiator in quite a few swaps..

RADIATOR.jpg
 
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