LS swap question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Nick_c10 · 11-13-2018, 03:53 PM

I’m about to do an LS swap. As far as mounting the motor are there any modifications I will have to do to the firewall or anything else or does it bolt right in with the new motor mounts? Thanks in advance.

**1971Stepside** · 11-13-2018, 06:46 PM

Welcome to the board. No modification to the firewall on my 71. Not sure what year or LS you are working with. One thing I can tell you is to do plenty of homework. Know your AC plan, your header plan, your engine mounting plan, etc. Each piece will impact the next one. I used POL engine stands with LSX innovation adjustable plates. Kept the engine in near the same spot as the original small block. Good luck.

**mongocanfly** · 11-13-2018, 07:05 PM

/\/\/\..what he said....what yr truck,what trans?...more info please..don't expect everything to just bolt back together...remember these engines/trans wernt designed for our old trucks..

lutronjim · 11-13-2018, 11:20 PM

I put a LC9 with a 4l65e tranny in my 1970 C10. I bought motor and transmission mounts from BRPhotrods inc. See http://www.brphotrods.com/.
This was 'bout 4 years ago - I now see they have all sorts of kits.

It bolted in with no mod to frame nor body. It also has the correct trunnion angle. A 90 chev drive shaft with an adaptive u joint fit - no vibrations.

Lots of luck with project.

Nick_c10 · 11-13-2018, 11:45 PM

I haven’t bought the LS motor yet, I have my current motor and tranny sold, just waiting to find the right one. I have a 68 shortbed stepside 2wd. I am probably going to go with a 5.3 with the 4L60e tranny just because the 6.0 with the 4L80e is a lot more expensive. Thanks for the advice guys.

**Clyde65** · 11-14-2018, 03:45 PM

Nick,

Don’t count the 4.8 out! I have one and it gives plenty of power for me.

Good luck!

Nick_c10 · 11-14-2018, 05:35 PM

I’ll keep that in mind Clyde.

tbrown5079 · 11-17-2018, 06:24 PM

I also agree with Clyde, very happy with my 4.8. All I need!

11-13-2018, 03:53 PM	#1
Nick_c10 Registered User Join Date: Jan 2015 Location: Rapid City SD Posts: 31	LS swap question I’m about to do an LS swap. As far as mounting the motor are there any modifications I will have to do to the firewall or anything else or does it bolt right in with the new motor mounts? Thanks in advance.

11-13-2018, 06:46 PM	#2
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,928	Re: LS swap question Welcome to the board. No modification to the firewall on my 71. Not sure what year or LS you are working with. One thing I can tell you is to do plenty of homework. Know your AC plan, your header plan, your engine mounting plan, etc. Each piece will impact the next one. I used POL engine stands with LSX innovation adjustable plates. Kept the engine in near the same spot as the original small block. Good luck. __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

11-13-2018, 07:05 PM	#3
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,581	Re: LS swap question /\/\/\..what he said....what yr truck,what trans?...more info please..don't expect everything to just bolt back together...remember these engines/trans wernt designed for our old trucks.. __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

11-13-2018, 11:20 PM	#4
lutronjim Registered User Join Date: Dec 2013 Location: Dunwoody,Ga Posts: 443	Re: LS swap question I put a LC9 with a 4l65e tranny in my 1970 C10. I bought motor and transmission mounts from BRPhotrods inc. See http://www.brphotrods.com/. This was 'bout 4 years ago - I now see they have all sorts of kits. It bolted in with no mod to frame nor body. It also has the correct trunnion angle. A 90 chev drive shaft with an adaptive u joint fit - no vibrations. Lots of luck with project.

11-13-2018, 11:45 PM	#5
Nick_c10 Registered User Join Date: Jan 2015 Location: Rapid City SD Posts: 31	Re: LS swap question I haven’t bought the LS motor yet, I have my current motor and tranny sold, just waiting to find the right one. I have a 68 shortbed stepside 2wd. I am probably going to go with a 5.3 with the 4L60e tranny just because the 6.0 with the 4L80e is a lot more expensive. Thanks for the advice guys.

11-14-2018, 03:45 PM	#6
Clyde65 1965 Chevy C10, 2005 4.8L/4l60 Join Date: Aug 2004 Location: DFW Texas Posts: 8,539	Re: LS swap question Nick, Don’t count the 4.8 out! I have one and it gives plenty of power for me. Good luck! __________________ Clyde65 Rebuild of Clyde http://67-72chevytrucks.com/vboard/s...84#post8338184 69 Aristocrat Lo Liner build http://67-72chevytrucks.com/vboard/s...84#post7561684 *support our troops!*

11-14-2018, 05:35 PM	#7
Nick_c10 Registered User Join Date: Jan 2015 Location: Rapid City SD Posts: 31	Re: LS swap question I’ll keep that in mind Clyde.

11-17-2018, 06:24 PM	#8
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: LS swap question I also agree with Clyde, very happy with my 4.8. All I need! __________________ tbrown's 56 Cameo Build



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