oldhog71

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.

71 Vert LS1

On my 71 C3 LS swap I used 2002 Camaro front accessory drive stuff. Worked well.

73ls1

I just bought a Holley Mid Mount system , I will be installing maybe this week, The system will tuck all accessories real tight, If I get it installed I will post photos,

oldhog71

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.

cagotzmann

What is the spacing of your Dampner , or are you planning on replacing the dampner?

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

Vette5311

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.

73ls1

The kit I bought is a 20-185bk, A guy on C3 ls swaps on Facebook has installed the Holley system,

oldhog71

Thanks cagotzman, I will look into that.

jd71

Just installed Holley’s mid mount kit in my ‘71… motor mounted in stock location… fits like a glove!

Yrock

How are you routing the lower radiator hose? I see a lot of people opt for a straight neck, is that possible with the mid mount setup?

jd71

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).

todds74

I'm using the Holley mid mount.

ToastedPirate

Reviving this thread - Does anyone know if you can buy the holley midmount bracket and use your own alternator/PS pumps? Is it just a pump from an LT1 Alternator and pump?

cagotzmann

Important part is the dampener spacing which usually requires specific parts with pulleys & spacing to match.

So usually the stock parts don't adapt well.

ToastedPirate

So i could potentially get away with getting the bracket and the dampener set. Thanks!.
Im just playing with ideas before I order anything.

cagotzmann

So starting with the 3 options available for LS3 see below. Check what you have now. or what you are expecting, each has some pro's and con's.

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.