4.3/LS Swap 86 K15

[smwebb11]

Hey guys, I haven’t been able to find any info here or otherwise, so hoping someone knows.

I have an 86 K15 that had a factory 4.3 with an SM465 4 spd. Based on another forum, I purchased some Carshopinc plates that bolt to the engine and slide it back about an inch. This keeps the transmission in the same place, but compensates for the difference in length between a 350 and an LS. 350 K15 to LS seem to be a fairly common swap as compared to my V6. My issue is when dropping the engine in, it hit the back of the firewall before the mounts on the engine ever reached where they bolt to the frame.

For trucks like mine, is the cross member and towers that the engine mounts bolt to different? Or in different locations?

This is a long shot, but HotRodPC posted 5 years ago he had several of these towers/stands and mounts on hand. I was going to message him, but the forum wouldn’t allow.

I appreciate any help or advice!

 

[smwebb11]

I think I have it figured out and wanted to update in case someone else comes across this.

Basically, the K10 and K15 use different frame perches that the frame side motor mounts bolt to. I thought initially I may be able to slide my V6 frame perches forward, but based on some info I researched, they would be moved to a different angle and not bolt up to the engine.

In short, to bolt an LS to a K10/15 with an original V6 and SM465, you need:

V8 4X4 Frame perches
Frame side engine mounts
V8 4X4 Clamshell mounts that bolt to the engine
Setback Plates that mount between the block and clamshell mounts.

CarShopInc makes these and set the engine back an 1” to keep the rest of the driveline in the original location.

The next thing I need to figure out are the support rods from the bell housing to the engine. These originally bolted between the clamshell mounts and the engine. I’ll have to check clearance for everything one my parts are delivered.

 

[brianmusil]

I think v6 frame mounts are in a different location than v8 mounts. If you find a set of used v8 braces you should be good