LS and 4L80E in a 70, using orig mounts? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

forcd02 · 01-04-2017, 04:56 PM

Been working mostly on the bed, waiting on stuff from the sand blaster, so I yanked out the six banger and trial fitted the 5.3 and 80E trans. I had some old mount adapters left over from another project, so I used them along with the six cyl mounts-I rem. the bolts from the frame mounts so I could move stuff around, bolted everything on the engine and dropped it in-I may have to weld up the top holes in the frame mounts and redrill-biggest problem I see is the 80E pan is going to hit the cross member where the six cyl bell housing was mounted-I may be able to trim it, and cut the body flange.
Curious if anyone has used the stock frame mounts on an LS conv., and if you had clearance problems with the cross member installing an 80E.
I have a new cross member for the trans-the truck pan hits the front cross mem., but I have a Holley pan I can use for that.

darrellyates · 01-04-2017, 05:32 PM

I swapped a 5.3 and 4L60E... Not sure about difference between the "60" and "80"... However, I used some tubular mounts that bolted right into the stock motor mount holes. The worked fine, but I wound up clearance issues with headers. "Shorty" headers seem they would have avoided the interference; and I'm using them on my later conversion.

I used an aftermarket cross member for the trans. Removed the factory one, and the new one bolted right in, no problems. The mounts and cross member were from CPP.... Yeah, I know, I've read the vendor section and complaints, but everything I got from them worked and was delivered promptly. So, no complaints from me.

Think I had a couple of hundred in the mounts and cross member. It's been several years, so I don't know. Lots of people have generic trans mounts that bolt in and will work.

Good luck! You'll love the engine!

72MARIO · 01-04-2017, 06:24 PM

I have a 6.0 4l80 in my 68 suburban low hump cab and it fits with out hitting anything. original V8 mounts using dirty dingo sliders engine is all the way forward.

You can remove the manual transmission crossmember as auto trucks did not come with it from the factory.

forcd02 · 01-04-2017, 06:50 PM

Thanks for the replies-I was wondering if a truck with an auto came without the crossmember, since the bellhousing sat on it-rem it would cure the problem.
I didn't know there was an LS section, thanks

01-04-2017, 04:56 PM	#1
forcd02 Registered User Join Date: Nov 2016 Location: woodbine, md Posts: 15	LS and 4L80E in a 70, using orig mounts? Been working mostly on the bed, waiting on stuff from the sand blaster, so I yanked out the six banger and trial fitted the 5.3 and 80E trans. I had some old mount adapters left over from another project, so I used them along with the six cyl mounts-I rem. the bolts from the frame mounts so I could move stuff around, bolted everything on the engine and dropped it in-I may have to weld up the top holes in the frame mounts and redrill-biggest problem I see is the 80E pan is going to hit the cross member where the six cyl bell housing was mounted-I may be able to trim it, and cut the body flange. Curious if anyone has used the stock frame mounts on an LS conv., and if you had clearance problems with the cross member installing an 80E. I have a new cross member for the trans-the truck pan hits the front cross mem., but I have a Holley pan I can use for that.

01-04-2017, 05:32 PM	#2
darrellyates Registered User Join Date: Jul 2016 Location: Gallatin TN Posts: 376	Re: LS and 4L80E in a 70, using orig mounts? I swapped a 5.3 and 4L60E... Not sure about difference between the "60" and "80"... However, I used some tubular mounts that bolted right into the stock motor mount holes. The worked fine, but I wound up clearance issues with headers. "Shorty" headers seem they would have avoided the interference; and I'm using them on my later conversion. I used an aftermarket cross member for the trans. Removed the factory one, and the new one bolted right in, no problems. The mounts and cross member were from CPP.... Yeah, I know, I've read the vendor section and complaints, but everything I got from them worked and was delivered promptly. So, no complaints from me. Think I had a couple of hundred in the mounts and cross member. It's been several years, so I don't know. Lots of people have generic trans mounts that bolt in and will work. Good luck! You'll love the engine!

01-04-2017, 06:24 PM	#3
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,052	Re: LS and 4L80E in a 70, using orig mounts? I have a 6.0 4l80 in my 68 suburban low hump cab and it fits with out hitting anything. original V8 mounts using dirty dingo sliders engine is all the way forward. You can remove the manual transmission crossmember as auto trucks did not come with it from the factory. __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

01-04-2017, 06:50 PM	#4
forcd02 Registered User Join Date: Nov 2016 Location: woodbine, md Posts: 15	Re: LS and 4L80E in a 70, using orig mounts? Thanks for the replies-I was wondering if a truck with an auto came without the crossmember, since the bellhousing sat on it-rem it would cure the problem. I didn't know there was an LS section, thanks



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