At first I was reluctant to accept the LS1. I thought "oh yeah... it's probably a pretty good engine for someone else, but I'll stick with the proven gen1 SBC"
I'll confess, it was denial... something that's probably pretty common among us Thirdgen owners. I mean it can be tough to accept, when your project that you've been planning and buying parts for for so long is suddenly topped by the new kid on the block.
But eventually I became a believer, because in truth, the LS1 in near stock form gives the kind of performance that I'm personally looking for, in a package that weighs about 100 lbs less.

The difficulty of the swap is another thing that steered me away from the LS1.
The cost and the down time would mean being without my car for several months since I'd be doing most of the labor myself after work.
But then after noticing the performer RPM intake for the LS1, things began to fall into a different perspective, especially if the intake system is all it's claimed to be in the catalog.

Anyhow, I'm basically unfamiliar with the LS1, outside of having looked at them under the hood of some other guy's cars, a few test rides, and reading about as much data as I could search out.

So I'm curious whether anyone here has tried the LS1 Performer RPM intake yet.
Also, according to the info in the Edelbrock ad, it sounds like it should be possible to accomplish the swap using my existing 700R4 tranny rather than having to swap in the newer 4L60. Correct?
In which case, I'm assuming that the original tranny would remain in it's original position, as opposed to the trans crossmember mods that are nessecary with the EFI LS1 - 4L60 package.
And if all that were true, it would change an LS1 swap into a "weekend project" rather than an "all winter" project. which makes it all the more attractive to me.

So now I'm just wondering if there's someone who could substantiate any of the info that I've read. Especially the part about the LS1 block bolting directly up to the 700R4.

Here's a link to the Edelbrock site, unfortunately I couldn't link directly to the specific page for the LS1 intake, but the page is easy to find.
http://www.edelbrock.com/

Thanks for any advice

 

You will need an adaptor plate to allow the 700R4 to bolt up, as well as new motor mounts. but other than that, it should be a fairly straightforward swap since you won't have to worry about wiring.



*Edit* Well I'm the dumbass for not reading the entire add before posting. I would call Edelbrock and double check about the "trans bracket" and see just what it does. I have a feeling its just for the throttle and trans cable bracket. Some how I doubt it comes with a bellhousing adaptor.

 

Thanks

Yeah, it sounds like the bracket that's included with the kit is some sort of a linkage thingee.

I'd love it if a carbed LS1 would fit in there with just some mods to the engine mounts.
I'm sure there'd be some custom fabbing to be done with the exhaust, fuel lines, radiator hoses, and a few other things too. But if that's it, then it should be a pretty simple swap.

Even though I wouldn't be doing this til next year, it would be good to find out as many facts as possible about the feasibility. Because if my project is going to be taking a new direction, this is a good time to make the decision, before I invest in a set of expensive heads for my SBC motor.

Anyone else??

 

you don't need a bellhousing adapter. your 700r4 will bolt up.

 

to an LS1? I dont think so.

 

Nope, won't work. The bellhousings are different.

 

If I recall correctly, it will, the original bellhousing will work but doesn't have 1 bolt hole. I think i've spoken with someone on camaroz28.com that did it and hasn't had a problem without that one bolt.

 

Oh thats right, its just the top center bolt that isn't used on pre-LS1 blocks anyway.

 

It has all the holes tapped for it to bolt up to the 700r4 except for one of the passenger side bolts. Four Wheeler magazine did a swap of a 6.0L and the 700r4 bolted right up and they haven't had any problems with it missing that bolt. They also said IIRC that if you tried to drill and tap the 6th bolt that you could bust through the cylinder wall of cylinder 8.

Adam

 

Well... This has gotten interesting
I'll do a search for that article in 4 Wheeler magazine.

Meanwhile, I'll assume that the 700R4 or other turbo hydramatic trannys will bolt up to the LS1 block.

Here's one more question

True or False

When swapping the EFI LS1 into a thirdgen, the 4L60 tranny must be used because the ECM (or PCM) won't function correctly without the transmission that's originally designed to be used with the EFI engine.
And the 4L60 tranny, being longer than the F-body's 700R4, makes it nessecary to relocate the rear mount, otherwise the original F-body driveshaft would not fit. Correct??

Are there any clearance issues other than the driveshaft length that would require the LS1 engine position to be relocated further forward?
Or... Assuming the 700R4 bellhousing will match up to the LS1 block, would the front to back engine mounting location be correct, when mounted in the standard position against the 700R4 bellhousing?

Thanks for the replys guys

 

Here is one for the LS1 guys, what do you do for ignition if you switch to carb? I didn't think that the LS1 was set up to accept a distributor (like the LT1), so do you use an aftermarket ignition system or what? Will the computer function just running the ignition?

 

Check the Edelbrock site. The carbed intake is a complete kit which includes a specially designed MSD ignition box that uses the existing factory components... No distributor needed.

Although if a guy were determined to use a dist, a toothed timing belt drive system that runs off the crank could probably be fabricated.

 

Thats cool. I have no intention of doin this, I was just kinda curious. Something to keep in mind when it comes time for a new engine. again.

 

IMO it's something that's worth keeping in mind.
If you arent someone who can afford to have the work done for you, and the only equipment you have to work with is a set of hand tools and a garage floor (like most guys) it simplifys the swap job greatly.

I guess nobody here has tried it yet.
I hope someone does and posts the results.

I won't be able to get to it til next year.

 

in hot rod magazine i beleive it was or car craft in the past like 3 or 4 months they had an article about it.

the housing is the same. but 1 bolt is moved to a diff location

and depending on the year of the genIII motor and which one it is. u may need an adapter plate or something for the flexplate in order for it to bolt to the torque converter.

i got the mag ill find it and try n find it online.

 

Thanks, I'll check back later.
Hope you can find it, I'm looking forward to learning more.

 

Hey... When asking about the LS1 bolting to a 700R4, maybe you should ask someone who has done it instead of listening to the bickering of others who havent. :P

The 700R4 will indeed bolt right up to the LS1 with the exception of missing one bolt which is no concern. No you will not need a bellhousing adapter plate. All you need to worry about is your spline, between the older and newer 700R4s. If you have an older 700R4 or you are using an LT1 TC than you will need a flexplate adapter, which you can get online or any machine shop can make. Its about as round as a CD and a 3/4 of an inch wide and all it does is allows the shorter rear shaft on the TC to fit into the back of the LS1 flexplate. If you have a newer 700R4 you can use an LS1 TC... or an LT1 TC, but then you would need the adapter. I run an LT1 TC with the adapter.

 

i dont own a scanner so ill just type it out


"All GenIII engines are dimensionally similar, except for different harmonic balancers, water pump offsets, oil pan configurations and rear crank offsets."

"On most GenIII engines, the crank rear offset is less than on a classic V8. The exceptions are the '99 through early '00 4.8/6.0L engines, which have the same offset as a classic V8. This permits bolting up a classic manual trans or classic auto trans and torque converter using the appropriate Gen III flywheel or flexplate without the need for an extended pilot bushing or crank flange spacer. With an auto trans, in some cases it may be necessary to slot the torque converter mounting holes."

 

Hey...When trying to offer information, maybe you should do it in a useful way instead of being rude about it.

 

I wasnt being rude. I see no rudeness.

 

OK, so now we're getting somewhere.
Knyghtmare, you actually have an LS1 that's mounted to a 700R4 in a '91.
Were there any interference issues besides the ones that are shown in the stickies here in this forum?

thanks

 

Nope none. Just the one bolt missing and you wont have a problem with that. It all just depends on the TC that you use like I explained above. I use a Midwest stall LT1 TC and when I bolted it up to the LS1 flexplate it didnt match the LS1 TC holes on the flexplate, but if you rotate the flexplate there are different hole patterns on the flexplate and you just have to find the right one for whatever TC that you use. Thats the only other issue I had, otherwise everything else works out just fine.

 

That's excellent... Thanks Knyghtmare

Thanks to everyone else too, for advice, or for just taking interest.

This changes my entire game plan.