LS3 transplant finally done!

joyridin' · #1 (**permalink**) 08-16-2015, 03:46 PM

It took a LOT longer than I expected, but the old 350 is gone and a new GM crate engine LS3 is in place and running. It is amazing how much better it runs now. Here are some pics:

Old 350

New LS3

Needs a bit of tweaking yet, but basically it is complete. Next is to get rid of the K&N filter and hook the air intake to the hood.

RallySnake · #2 (**permalink**) 08-17-2015, 11:57 AM

I would really like to know more about the improvements. I have considered this option.

joyridin' · #3 (**permalink**) 08-17-2015, 02:12 PM

If you already have a TKO, it is a lot easier as you have to modify the frame for a T56. The headers are the hard part. Drop me a PM with your email and let me know what info you need and I will send it to you.

750hp · #4 (**permalink**) 08-18-2015, 05:51 AM

There's a lot more going on in the engine bay with the new combination. Looks like a "here's how the factory would have done it" style about it.
Lots of guys over here are fitting LS2, LS3 and more recently the monster LSA supercharged motors. Very impressive power potential!

427SSSS · #5 (**permalink**) 08-18-2015, 05:55 AM

WOW! Nice, very nice.

PSB · #6 (**permalink**) 08-18-2015, 07:47 AM

If I ever build another Cobra, I'd have to seriously consider a LS3. Sooooo much easier to work on than old Ford engines.

G_Edmonds · #7 (**permalink**) 08-18-2015, 07:02 PM

I'm interested in seeing how you incorporate the hood scoop.
-Greg

joyridin' · #8 (**permalink**) 08-19-2015, 05:26 AM

Quote:

Originally Posted by G_Edmonds

I'm interested in seeing how you incorporate the hood scoop.
-Greg

That is going to be a little tricky. I figure it has to be 2 separate pieces that meet when the hood is closed using some type of flat air filter.

That is all I have for now.

joyridin' · #9 (**permalink**) 08-19-2015, 05:28 AM

Thanks for the compliments! I weighed the car yesterday and it is at a tick over 2000 pounds now. The FAST front end and loss of engine weight took quite a bit off.

Brooklyn-427 · #10 (**permalink**) 08-19-2015, 06:34 AM

Did you use ls/sbc engine mount conversion plates?

How is your f-r weight balance now?

looks like a professional installation, a job well done

joyridin' · #11 (**permalink**) 08-19-2015, 01:32 PM

Quote:

Originally Posted by Brooklyn-427

Did you use ls/sbc engine mount conversion plates?

How is your f-r weight balance now?

looks like a professional installation, a job well done

Yes, although the actual motor mounts had to be modified a bit. I got them from ICT Billet. Good stuff at pretty reasonable prices.

Right now about 47/53 give or take a bit. The trans is pretty heavy and I have 11" vented rears on the back. I still have the original 6 row? radiator. A new aluminum version will probably lighten it up quite a bit more in the front.

Brooklyn-427 · #12 (**permalink**) 08-19-2015, 02:10 PM

A alum case for the jag diff would ofset the weight balance some.

RallySnake · #13 (**permalink**) 08-19-2015, 05:59 PM

Be careful, a lot of those flat air filters do not have a flame arrester panel and you really need one if it's going directly over the intake.

GVS · #14 (**permalink**) 08-27-2015, 08:04 PM

Nice work! LSx engines are great and I am sure this made a BIG improvement on the drivability of your car. What did you use for exhaust? I would think this is the hardest part.

As a point of reference on the reliability of the LSx series, my 1999 Corvette is a summer daily driver which sees redline quite frequently. Its LS1 has 95k miles on it and has never been apart. In fact, the only repairs this engine has needed is a new water pump and accessory drive pulleys & tensioner.

Is your car an Arntz Type IV? I noticed it has a notch for distributor clearance on the rear edge of the hood.

joyridin' · #15 (**permalink**) 08-27-2015, 08:20 PM

I had a place called GP headers build them for me. I installed the engine, bolted plates to the heads where the header flanges would mount, then welded the old headers to the plate. They were able to duplicate this design.

It is a very late Type III.

lal Naja · #16 (**permalink**) 08-31-2015, 10:55 PM

Congratulations! Thanks for posting this. Well done!!! Now you've got me thinking? And I'm not sure it's a good thing.

Thor maine · #17 (**permalink**) 09-01-2015, 06:35 AM

Congratulations, she is a beauty!

Donunder · #18 (**permalink**) 09-01-2015, 06:59 AM

As long as you don't go past the thinking phase Arthur....

First -- there's no denying that the LS range of motors are good things. They are a sensational package. OK that's acknowledged.

Over here there are probably more LS motors going into new builds than any of the Ford derivatives for the simple reasons of affordability compactness weight performance and reliability. Hard to argue against. Yet my old Arntz continues to attract attention simply because it is old school with a big block Chevy a carbie and working side pipes. The restrictive Australian build requirements prevent any of these being used in a modern build, hence my car is a throwback to the past as far as our ADRs are concerned. I am aware that the US has a vastly more enlightened approach to the construction of ICVs than do we.

I would like very much to have an LSA powered Cobra but it would have to be a new build. I'm determined to keep my car old school because of its history and heritage. Sure it's now running a Fast IFS in lieu of the original MGB front end and I've replaced the old Muncie with a TKO 5speed to allow more relaxed highway cruising but if the time ever comes when the original motor expires, it'll be replaced by another 454, or preferably a 540. Good on joyridin' for his upgrade-- his car will be transformed and he'll have a ball with the loss of weight and effortless performance the LS3 will deliver but it's not for me, not in this car.