BOOSTED 76

Hey guys im new on the vette forum. I recently acquired a 1976 L-48 Auto car that is stock down to the air cleaner. Im a huge fan of the LS series engines (ive had several Forced Induction LS based engines). Ive been lurking on the swap thread for the C3. I see that alot of people go with the 4l60E or just a turbo400. I was planning on using a 4L80 with a manual valve body. So i have a few questions on the swap. Ill be using a LQ9 Iron block @ 370ci.

1) best motor mounts to use?
2) Has anyone mounted a 4l80 successfully?
3) is an intank pump the best to use? (ill use a return style setup)

I think thats all the questions right now. I know ill have more later. Any other tips or tricks would be much appreciated!

Thanks in advance!
Chandler

SuprJames

1) Are you talking about the motor mounts themselves or the adapter plates? The motor mount adapter plates you use depend on a lot of things like what headers you are using, the oil pan, if you're using rack and pinion, where you want to mount your AC, etc. The plates are all good quality, but some move your engine farther forward and some leave very little clearance between the firewall and engine. If you're talking about motor mounts, the I'd just use poly mounts.

2) I wouldn't use the 4L80. It robs quite a bit of power over the 4L60, weighs 45 lb. more, and is really unnecessary in most cases. What HP are you planning on running?

3) In-tank is more quiet which does not sound like a big deal until you've lived with an external pump for awhile. You should baffle your tank either way unless you plan on running with more then 1/4 tank at all times.

BOOSTED 76

1) yes i guess my post was uneducated....Im under the impression that you use the stock mounts with adapters? I meant the adapters used. The plan is to turn the C5 ls1 manifolds up and run twin turbos that will be slightly out of the hood, but for the time being probably just stock manifolds, whether its the truck ones or the stock ls1 vette manifolds (im not even sure if you can use the truck ones). Id like to have the motor somewhat pushed to the firewall to have room for the intercooler piping and such

2) Im aiming for 6s in the 1/8th and roughly 600whp. I dont like the size, weight, or parasitic loss of the 4l80 but im not sure how far i would have to build the 4l60 to get it to hold up to the boost launches. Ive only had powerful T56, and TH400 cars so im not familiar with the strength and durability of the 4l60. I have seen some go out under stock power in GTOs and F-bodys though.

3) Ok thanks for that info. Ill probably end up with an external. In my mind if you can hear the pump over the exhaust, then your car isnt loud enough! haha but I could see how that would be annoying.

Thanks for the info! this is great!

Garys 68

Um with that hp, you'll be eating GMs crappy 4L60s like breath mints...
torque converter apply solinoid failure ring a bell? I think it's 1370 code...crap trans..
Go for a built 4L80.
In tank OEM pumps have a reservior and integrated return. I'm running an external, but my LQ9 has sidepipes, so noise is not an issue.

BOOSTED 76

Yea thats what i was worried about when i install the turbos.
Which in tank pump did u go with that has integrated return?
Which motor mount adapters did you use?

Garys 68

My 68 with speedhound's 1" setback, original trans location mounts, were ok. But my trans would need the yoke cut and the trans housing bolts were way close to the firewall. With an auto...not an issue for you.
In tank pumps are dictated by what you want to spend. With a turbo, you never want to go lean...I had a supercharged boat....so get the best...

BOOSTED 76

Ok thanks for the info! do you have pics of your set up by chance? What stock style manifolds should I use with those adapters?

hugie82

I drive a 2003 SS Silverado with the LQ9 and it runs the 4L85 trans. I can't kill it but I hear the trans ecm to run it is big bucks!!!

BOOSTED 76

Yea so i hear Thats why I was wanting to run a manual valve body to eliminate the controller. I dont think hardly any tuners have figured it out yet

SuprJames

I thought the 2006 and back engine ECM controls the transmission without another controller.

BOOSTED 76

I think you're correct on all GM vehicles <06 but the HD trucks with the 4L80s. I believe they require a separate controller?

A 6spd auto from the c6 vettes/Escalades would be pretty sweet too! Those are very expensive from what i can tell. 6L60?

BOOSTED 76

So has anyone successfully swapped a 4L80 into a C3? Im sure the crossmember would need some mods

Garys 68

For turbos some have been using the truck manifolds flipped.
As for a 4L80, do a search, I think crossmember and tunnel mods were needed.
Here's a link to my build.
http://www.vettemod.com/forum/showthread.php?t=2731

Garys 68

One other thought, the LQ9 has a pretty high compression ratio, why not use an LQ4? It has lower compression, cheaper, and more available.

BOOSTED 76

nice swap! that fiberglass intake is sweet! Thanks for the pics also. I have heard the same on the truck manifolds. That sounds like the path ill be taking. Ill have to read up on the 4L80 and the mods required. O and for the LQ9...The only things stock about it are the crank and block. Pistons and rods will be forged. Its just the block i happened to come across.

Also on the thread with your pics...Did you use the stock wiring harness from a truck or an aftermarket? If so who makes them?

Thanks,
C

7T1vette

Why do folks go looking [and paying] for a bone-stock Corvette, then pull the important components out and stick new stuff in it? Why not just buy a modified car to start with? Believe me, I'm all for folks doing what they want, but why spend extra ca$h for a 'stock' vehcile and then go altering that 'stock' condition? Beats me....

Garys 68

I got mine with the truck harness and computer and modified it myself.

Garys 68

LOL, who started with a stock vette? I got mine in a partial trade for a boat. It had a badly "hoped up" 350 SBC replacement motor. You know, put the biggest cam in and it will go fast. The trans was beginning to show its age and the clutch was slipping. Somehow the car had a 3.08 rear from an auto car....
Now I get 20+ mpg, MUCH better performance, more reliability, easier starts, and cold AC keeps my fat old a$$ from sweating on 100 degree days.

BOOSTED 76

This car was sitting in a field for 7 years...the bumpers rotted off of it.I didnt "go looking or paying" for a stock vehicle. It was almost like a barn find except without the barn. It needed a starter a battery, new fuel lines, brake lines, calipers and bunch of other stuff. How do u know the condition of the car or how much i paid for it???? I dont believe i said what condition it was in other than it being stock. W/e floats your boat i guess....O and btw the car has 83k miles on it....the L48 runs like a top. Just got it running today.

After having some quick LSx cars, I dont think it gets much better than 620whp and 25mpg (interstate).

Back to the topic:

Is it possible to use an F-Body harness?

Ive also been reading up on the accessory drive system.... the ls1 F-body acc seems to be the weapon of choice???

I searched this forum with a few results on the 4L80 swap that were very helpful. However I havnt found anyone running a manual valve body. I like driving manual valve body cars and this would also eliminate the expensive controller. Im 90% sure they make a conversion for it but im not sure. Anyone know of a company that does?

Thanks,
C

Garys 68

F body accessories seem to work, the alternator fit can be tight.
All the LQ9s were DBW, If you go to the cable TB f body harness you might be better off getting the f body computer too. Look at LS1tech site, there are a few threads on coverting.