krwyellowZ28

iTrader: (10)

In the next month my brother and I will be tearing my dad's 1970 GTO Judge apart to swap the non #'s matching 400/TH400 for an LS1/4L60e out of a '99 Z28. I want to have as much of the swap planned out and ready before turning the first wrench, so any help, suggestions, or recommendations from all the guys that have been there & done that with the A-body swaps would be a huge help.

Background:
I talked my parents into buying the Judge in 1998 when I was 13 yrs old as a weekend toy... my dad has always been a gear head, so it wasn't a hard sell. Long story short, we enjoyed it for a lot of years, but hated to poor street manners of the very healthy 400, no choke, and 4.11 gears behind a TH400. The bottom end let go 4 years ago and it has been sitting ever since.

Goals:
The car is going to be a "Muscle Touring" build... we want to keep the tough aspect of the stripped down muscle car, but with street manners that would make it driveable every day.
- Be able to bump the key once in the morning and it settles to a nice lopey idle.
- Drive down the interstate at 70 mph turning less than 3100 rpm
- Drive nice in town but have power to match the look when its needed.

Parts already sourced:
- Full Eddelbrock swap kit before they were discontinued: Engine mount adapter plates, coated LT headers, full X-pipe exhaust.
- Rick's stainless steel fuel injection tank
- Affco aluminum radiator
- LS1/4L60e from '99 Z28. I bought the whole car, so I'll be using the F-body oil pan, accessories, PCM, harness, and cable TB.
- Comp 222/224 .566/.568 112 cam, 918 springs, and Trick Flow PR's
- I'll modify the stock harness with the help of a couple friends with LSx swap experience and the info I've gathered off Tech.
- '99-04 Vette FPR/Filter mounted in front of the tank with Russells twist-lok line and fittings for the rest.

Parts I NEED to source:
*This is where I need the help and recommendations. I have the major variables locked it (eng, trans, mounts, oil pan, etc.) I konw I'll have to notch the K-member to fit the f-body pan, which is fine with me in order to keep the ground clearance

- Will be buying a Yank SS3600 to match the cam, but still have good street manners

- Throttle cable: is the f-body cable ok? I know a lot of guys use the cable out of an Express van.

- Jeep Steering Box: 92-98 Jeep Grand Cherokee steering box and will bolt right up with a metric rag joint from mid 80s full size truck

- Gauges: I would like to use the OEM rally pak gauges... is there any other way for the speed to be used other than with a convertor box?

- Shift linkage: I haven't read much on this part... I'll be going to a factory column 3 spd shifter.

- Engine mounts: Based on recommendations below, I'll use the Energy Suspension tall/narrow (non 307) mounts and matching stock frame stands.

- Possibly oil port cover (12551595) for the oil pressure sending unit.

- Driveshaft: Probably just have a local shop shorten the stock DS until a beefier unit is needed.

- Anything else I missed? I know things like radiator hoses and intake ducting will come up, but I'm open to any guidance I can get.

Here's a pic of the Judge back in the day:


[img][/img]

And this is where it sits today


Picking up the drivetrain donor: 1999 Z28, LS1/auto, 112k miles


Thanks in advance for the advice. I've learned and read a ton of information on this swap, but there is no substitute for 1-on-1 sugestions from someone that's already done it.

Kyle

spacemanspif

iTrader: (5)

https://ls1tech.com/forums/conversio...9-ta-vert.html

I hope you have read through this already. Probably has a lot of the fitment information you are looking for.

krwyellowZ28

iTrader: (10)

Wow... that is an aweomse build , but it doesn't really help me much with some of the questions I have for my GTO project. Plus, that car had a much higher build budget than mine. I've learned a lot from guys like bczee and Bsharpe's posts and threads.

Thanks for posting though! Its always nice to get ideas.

Project GatTagO

iTrader: (7)

Cool to see another LS powered 70 GTO. My build thread has details you may be interested in:

https://ls1tech.com/forums/conversio...ion-2-0-a.html

Andrew

72montecarlo

Not a real judge is it?

krwyellowZ28

iTrader: (10)

Yep, its a real judge... we have one of the build sheets and PHS documentation.

oldgoat69

I have done a similar swap, LQ9/4L60E into my 69. I am happy to share information. I do have several photos and can provide part numbers. Your swap will be different since you are using the F-body accessory drive. I can give you input on trans crossmember mods you may need to make.

krwyellowZ28

iTrader: (10)

oldgoat, that would be great. For the x-member it sounds like cutting and flipping the mount is common... did that work for you? Also, i remember reading where the Pontiacs don't have the right holes drilled in the frame like a chevelle. What motor mounts did you use (i was going to order some Energy Suspension sbc chevelle motor mounts)?

One thing i just realized I overlooked is the driveshaft... I need to find some info comparing lengths of the TH400 vs. the 4L60e.

PontiacPOWA

on our 69 GTO project we used the same edelbrock mounts and headers with small block chevy frame mounts. the bolt holes don't line up exactly on the frame so the mount kinda hangs off the front of the x member- it works though. we also used an f-body accessory drive which clears, but with little clearance (less than 1/2 inch) between the alternator and the steering box- but again, it works.

as far as the fuel system, we welded a sump on the bottom of the stock tank (you wont have to worry about that with the ricks tank) with a walbro 255 inline pump. we started off with a vette filter/regulator but the part happened to be defective and was replaced with an aeromotive regulator. a good cheap source for some electric fans would be off a ford windstar minivan. fits the stock rad perfectly with some slight trimming and cools rather well especially for 50 bucks.

i have a small build thread with a few pics in it too. good luck with the swap man

oldgoat69

The TH400 shaft is too short. I had a TH350 shaft shortened and balanced. The slipyoke is the same. As for the cross member, mine is a convertible, so it is a bit different. None the less I simply sectioned the trans cradle part out and used some flat stock to allow me to drop it to make the angles. I will get you a picture if that helps. I never took any of that adventure.
I used Dougs headers and mount plate kit with frame stands for a small block Chevelle. I also used Energy Suspension mounts, I have the part #. My biggest concern was to get the engine as low in the chassis as possible to make hood clearance. You should not have any of those issues. All in all the swap was pretty simple. If not for the supercharger plumbing I would have had it done in no time.
I also used a 96 Impala SS fuel tank. The added capacity was a bonus and outweighs the modification to the trunk floor. I can also supply pictures.
I am now in the process of prototyping a rear coil over conversion for A-bodys. This is proving to be a bit more complex than my original plan.

chuckd71

iTrader: (23)

Cool car. I dumped the return style fuel rails and went the vette regulator route, mainly just to prevent having two lines worth of fuel running the length of the car. Shiftworks might have something that will take care of you linkage.

krwyellowZ28

iTrader: (10)

oldgoat, feel free to post any picture you think might help... I'm sure other members would like to see them as well. Do you happen to remember the finished length of the new driveshaft?

And the more I think about it, I think I might go ahead and get some billet fuel rails to go the Vette FPR route.

krwyellowZ28

iTrader: (10)

Can anyone share the motor mount part #'s they used? Like I mentioned before, I'll use the Eddelbrock adapter plates and then planning to order some Energy Suspension SBC motor mounts, but not sure if I should use the 3-1115g (short wide) or 3-1115r (tall narrow). Also, will my stock Pontiac 400 frame mounts be ok for the swap?

Project GatTagO

iTrader: (7)

First you will need to change the Pontiac frame stands to Chevrolet 68-72 SBC/BBC NON 307 frame stands. Then you can use the tall and narrow Energy Suspension mounts.

Andrew

krwyellowZ28

iTrader: (10)

Thanks... that is exactly the info I needed. And for anyone else doing an LS swap, I just paid for a '99-04 Vette FPR/Filter for $23 shipped on Amazon.

big johhny

I just started my 70 Lemans Sport conversion this week. I am installing a LS2 and 4l65E from a 2005 GTO. I used the stock Chevelle frame mounts from OPGI and a set of Anchor 2283 rubber mounts with a set of adaptor plates I got on Ebay. The block has not quite made it down on the mounts yet, about 1/2 a hole to go, I am working on it.

I took the LS2 oil pan off as well as the compressor and alt. This allowed me to easily get the motor in the car. I will probably go after the Mast pan and Kwik perf brackets and just suck up the cost.

I also have to get some headers, luckily the GTO has a set of Kooks 1 7/8" headers and non cat pipes I can sell to repop cash for the swap headers. I just have to figure what brand, probably Husler's from Hedman.

I'll keep you posted on my progress and headaches if you do the same.

krwyellowZ28

iTrader: (10)

Our swaps should be very similar, but i plan to keep the AC and alternator locations with the f-body pan ... even if i have to cut the x-member. i want to be tearing the parts car apart right after christmas.

oldgoat69

Big Johnny, take a look at the Dougs headers first. Best ground clearance of the lot.

big johhny

oldgoat69, I would but me and Dougs don't play well, I had issues with them when pertronix took them over and they did not come through and I got screwed.

What block is that in the picture???

oldgoat69

I am using an LQ9/4L60E. I have retained all of the truck accessories including AC. Even with the blower it all fits under the hood. The only thing I needed to change was the power steering pulley to clear the steering box. One further change will be to decrease the PS pump pressure to pick up some steering feel.