Early planning ls swap in my 69

[Crusty69]

I have a 69 long bed that has a 400 sbc that was swapped in around 72 if I had to guess. I’ve had the truck about 5 years and it’s driven a lot. I’m burning tons of oil and reliability just isn’t what I’d like it to be.

The goal is a smooth DD that I can pull out 3-4 times a week.

Going with tanks inc tank with 255 lph pump
Stock 6.0 lq4 or similar whenever I can find it. Will do a mild cam swap and nothing else.

Speed engineering headers

Haven’t even looked into mounts yet, what do you guys like?
Planning 4l80e for the strength over 4l60e and wanting overdrive. Currently a 3 speed truck.

Should I stick with gm ecu or go Holley?

Will all the truck accessories work without moving them? Planning to run a/c with the new setup.

How does integration with the factory gauges go?


I’m sure these questions have been answered but trying to consolidate my info and maybe have a place to document as I do this. I plan on buying everything up front and doing it all over a weekend or two.

[clay68c10]

I'm running the Hooker/Holley mounts. I made my own transmission x-member. Speedway makes the same for less $$
You'll need a low profile pan. I used CTS-V, but there's a few options for that.

https://www.speedwaymotors.com/1967-...it,487640.html

The LS truck low mount a/c works fine with this setup. There's some info in my build thread for hoses, fittings, evap, condenser, etc.

I'd run the GM computer, it will do everything you need it to do.

Factory gauges can work. A few of us have made that happen. The speedometer is the only hard one. I have a TKO so it was easy for me.

[Crusty69]

Originally Posted by clay68c10

I'm running the Hooker/Holley mounts. I made my own transmission x-member. Speedway makes the same for less $$
You'll need a low profile pan. I used CTS-V, but there's a few options for that.

https://www.speedwaymotors.com/1967-...it,487640.html

The LS truck low mount a/c works fine with this setup. There's some info in my build thread for hoses, fittings, evap, condenser, etc.

I'd run the GM computer, it will do everything you need it to do.

Factory gauges can work. A few of us have made that happen. The speedometer is the only hard one. I have a TKO so it was easy for me.

I have been going back and forth on the Holley vs gm harness. I thought the Holley might make it easier if I mod things down the road but maybe not. It seems less clunky.

[clay68c10]

Originally Posted by Crusty69

I have been going back and forth on the Holley vs gm harness. I thought the Holley might make it easier if I mod things down the road but maybe not. It seems less clunky.

It is cleaner to start with, but the factory harness can be thinned out a lot. I guess it's a matter of what you want to spend money/time on and the capabilities of either PCM and how those match the end result you're looking for.

[WorldsCrappiestTruck]

For a daily driver....you honestly can't go wrong with a bone stock junkyard 5.3/4L60E, or even a little 'ol unappreciated 4.8. The 6.0 might have more down-low grunt but will definitely be thirsty.

I've had good luck with Speed Engineering headers, any generic slider-LS mount you can find on Summit or at various vendors; they're all sorta a variation on the same design.

I'd recommend a transmission crossmember with notches or clearance for exhaust coming off the headers.

For a harness....stick with GM stuff unless you want to do all sorts of high-end build / tuning afterward and can take advantage of fancier newer options the aftermarket offers. Worth it to buy HPTuners as well IMO.


Simplicity is key here. The more generic you keep it, the more relevant the HUGE wealth of information on LS swaps is for you.

[NCDEERE]

I used the generic aluminum plate mount adapters. SE headers fit perfect. I bought the really cheap trans mount from Ebay and it fit great. I went Holley mainly because I got tires of paying someone for credits to get tuning done. I also used a hydra boost unit and MC from a 2006 GMT800 truck with an Ebay adapter plate to mount to the firewall. I have brakes that are amazing.

[WorldsCrappiestTruck]

Originally Posted by NCDEERE

I used the generic aluminum plate mount adapters. SE headers fit perfect. I bought the really cheap trans mount from Ebay and it fit great. I went Holley mainly because I got tires of paying someone for credits to get tuning done. I also used a hydra boost unit and MC from a 2006 GMT800 truck with an Ebay adapter plate to mount to the firewall. I have brakes that are amazing.

Can you share the details / photos on the Hydroboost and eBay adapter?

[NCDEERE]

Originally Posted by WorldsCrappiestTruck

Can you share the details / photos on the Hydro boost and eBay adapter?

The adapter plate is from eBay, I just searched 67-72 c10 hydra boost mount plate. I scrapped a truck for the engine and tranny for another project and pulled the hydra boost unit, the lines and the PS pump from the donor. Since I used the factory lines and they had a cooler in the return I mounted it out front since the pump is running steering and brakes. I used a new 2006 GMT800 master and had to adapt one line as seen in the photo. You can use your PS pump and tee the return lines but the one I used has two returns. I had to cut the end off of the pressure line to the C10 steering box, replace it with a SAE fitting and re-flare the line. I still have drum rears and they are really sensitive. I plan to go with disc rears later. I cut the rod end from the vacuum booster and threaded it and the hydra boost rod end and used a threaded rod coupler nut so I had some adjustment. Match the vacuum boost rod length as close as possible. If you plan to keep disc/drum I would look into a later square body master so the piston size isn't so large.