1970 LS SWAP, Accessory Drive
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From: Arkansas
1970 LS SWAP, Accessory Drive
My question is what spacing did you use on the engine front accessory drive? I know there is not any room for error, but what is best corvette spacing, or truck spacing. I am not sure of the difference in the dimensions.
Thread Starter
Intermediate
Joined: Sep 2021
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From: Arkansas
73ls1, I had previously bought a Holley Accessory drive part number 20-155. It would not fit for 2 reasons. The lower bracket hit the engine mount, and the water pump would not mount because of the heater inlet and outlet hitting the upper control arms.
Melting Slicks
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My LS3 /480 crate came with the corvette / CTS-V Spacing. This forces accessories to the widest positions. I used the holley 20-135 PS / Alt brackets which required a smaller dia PS Pump pully to clear the a-arms.
The further spacing f-body is the most common LS3 / C3 used. Gives you more options to mount alternator / PS pump closer to the block. From holley below, to determine your starting point.
For engine mounts I used ICT LS / SBC Mounts.
Heavy Duty LS Swap Engine Mount Adapter SBC to LS Motor Conversion | 551128-301 ICT Billet
The water pump / heater hose is also a common a-arm issue. It depends on what a-arms you have. I have SPC upper arms which cleared without mods.
here is the power steering side. I also reversed the a-arm bolt to clear the PS pump pulley. Again possible due to SPC Upper arms. Removed all shims to MAX clearance. Adjustable SPC Arms for camber / caster alignment.
Here is my complete LS3 swap (1978 corvette).
1978 LS3 Swap Completed. - CorvetteForum - Chevrolet Corvette Forum Discussion
Last edited by cagotzmann; Feb 27, 2022 at 09:42 PM.
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If you can find an issue of Hot Rod magazine from November 2020 there is a pretty good tech article on using a LS car water pump with truck front drive with an adaptor kit from Dirty Dingo. Using cheap GM parts that can be sourced from a truck. 
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Verdad Gallardo
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I used swivel thermostat housing mr.gasket p/n2670 in accordance with Holley’s instructions. The neck that comes with the kit points right at the control arm, so it won’t work. I thought about using a straight neck, but it looked like it’ll put the hose into the tensioner. I’m running Dewitt’s LS bbc-sized rad and am using lower hose gates p/n 22437 (trimmed).
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Melting Slicks
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So usually the stock parts don't adapt well.
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Im just playing with ideas before I order anything.
Melting Slicks
Joined: Jun 2011
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Standard will have the widest foot print may hit upper control arms via PS pump pully.
Middle less options on alternator / PS pumps that fit.
Long may be very close to radiator , but the narrowest foot print , more options on alternator / PS pump placement, but may also hit the standard hood when closed.
My LS3 came with Standard dampner, And I selected PS pump / alternator parts same as my C6 2010 grandsport. Purchased direct using the GM part# from Chev dealer / parts stores.
The holley brackets where choosen vs the Chev brackets was based on price, but both use a similar placement. PS type 2 pump with remote reservoir , and C6 corvette alternator, many choices based on output specs.
The FEA ( front end accessories ) was the hardest part for my LS3 swap to make sure it worked.
