LS7 Swap into '73 Pro-touring Grand Am Build Thread
 

I thought I would start posting some information on my LS swap into my Grand Am. Following a long decision time, I decided I wanted to go forward with an LS swap. I have always been a "Pontiac" guy and knew going into this that I would not be satisfied with a traditional 5.7/6.0/6.2 motor after being used to the massive bottom end torque our Pontiacs make. That meant a stroker motor would be the only way to go. After doing a ton of research, joining the LS1 Tech web board, I decided to go with ERL Performance in Indiana. They specialize in dry sleeved LS motors to as big as 500 cubic inches. I spoke to them and we decided the best, and most reliable build was a 4" stroke motor. The bore is 4.130 which nicely equates to a Pontiac freindly 428 cubic inches. This was accomplished by sending them a Gen 4/5.3 aluminum block which will receive all of the tricks they build into all their motors. This will be a NA build. I am going to be looking for approximately 620 hp, but mild enough to drive daily if I want to...(which will never happen). As you all know the LS7 engine in the ZO6 Corvette makes crazy power with very mild cam timing. I decided to build an LS7, and have purchased a factory LS7 manifold, and am in the process of purchasing Brodix CNC ported LS7 heads from West Coast Cylinder Heads here in Ca. These heads will flow around 390 cfm at .700 lift. The great thing about the LS7 castings is you can run fairly mild cam timing in order to make great streetable power. I am working with Geoff at Engine Power Systems on the cam. He has designed a custom cam using his proprietary lobes specifically for my car and set up. The GA is heavy at 4000 pounds, but the LS will drop 200 pounds off that number. I did not want a real choppy idle, and I plan to run dual hi flow cats on this car for the pleasure of not having to smell it anymore. His cam specs are .631/.642, 226/242@.050, on a 115 LSA. This will give me a moderate idle with a little lope to it. Botton end power will be very good, and power will peak around 6500 or so. The entire build is going to run all stock GM electronics and EFI in order to keep reliabilty high. I will have the shortblock in a few weeks as well as the heads and will post some pictures then.

Factory LS7 block sleeves are not that strong. They are know for destroying engines from detonateing. It should put out the power your looking for, it would be better to match cam to heads flow.

If you are staying carburated go sollid roller you could get away with more duration and not have it as choppy. Then you can go with.700 lift and little more duration.

As I had mentioned in the post, this is not an LS7 block, it is an aluminum 5.3 Gen 4 block that was sleeved by ERL Performance, and bored to 4.130. There have been reports of LS7 blocks losing the #7 piston due to detonation which is caused by the fact that #7 is the last cylinder in line that is cooled. The block configuration that I have chosen is good to 800HP. The dry sleeve system replaces the stock cast iron sleeves with high strength ductile iron sleeves. These sleeves are made of ductile iron that is 3 times stronger than cast iron. The ERL sleeves are significantly longer and thicker than stock sleeves, this allows for up to a 4.125” stroke and a 4.185” bore. This is not a carburated motor, as I mentioned it will be all GM EFI. The factory intake is a ported LS7 from LS2 Portworks. See the link below for their built shortblock assemblies. I worked with an LS builder specifically to get the combination correct for my intended purpose, which is a powerful street engine, that can easily go 100,000 miles and maintain excellent driveability. A solid lifter cam and .700 lift does not accomplish that goal. Thanks

http://www.erlperformance.com/gm-ls-...e-short-blocks

Interesting build plan. I didn't realize you could use a 5.3 to build up to a LS7. I know you previously have done the EFI on your Pontiac block. That is something I was considering. Now like you I am interested in the LS swap. Please share all the details in this build. I would like to learn more about this too.
I just remembered that ERL Performance was at Holley LS Fest this past weekend. I talked to the guys about their blocks. I kept their handouts. Now I am going to go read them.

Paul

ERL Block
 

They are very well known in the LS circles as well as the import market. I am sure there were a good number of turbocharged and supercharged LS motors there running 1000 to 1500 horsepower ERL motors. I will be trying to keep a good log of my build as it progresses over the next year.

I have had nothing but bad experience with dry sleeved blocks. After few hundred miles later coolant starts to leak in cylinder, cooling system gets pressurized, ect. I prefer the wet sleeved, way better than dry sleeved. It's little more but it's worth all the trouble from dry sleeved blocks. I am not going to mention any names, have used more than one different machine for dry sleeved and ended up with bad disappointing results where blocks had to been swapped out.

That's just my experience, good luck with your build.

Did you use an ERL block????

Need proof of this...

Good luck on the build Stobin. Looking forward to the results.

Andrew

stobin, will be staying tuned with interest. unrelated, but what are you running for springs, shocks and A-arms? do you plan to change front springs because of the weight reduction of the LS versus Pontiac engine?

LS7 Swap
 

I already have a QA1 coil over set up with upper and lower Global West A-arms. I currently run 550 lb. springs. I also have a set of 450's that I will install to test out. The LS will drop enough weight to reduce my front to rear bias to 50/50.

Subscribed. Are you still running the TKO or switching to a T56?

One of the Pontiacs I have is a 74 GP. I want to lower this car a little. Currently I can measure 6" between the cross member and the ground. You seem to be up on this for your model. Do you know of a quality drop spindle I can get for this car? Or would you recommend lowering springs to do this job? I have been looking at the McGaughy's 7078 drop spindle but I know nothing about this company other than the spindles they make are made in the USA and of 4041 chromemoly forgings. I don't want to hijack your thread but it is tough finding this type of info on the 73-77 A/G bodys. I think your goals for your Grand Am are the same as mine for my Grand Prix. My 70 GTO is much easier to get suspension upgrade information for.

Thank you
Paul

Remember, the front suspension on the '73-'77 A and G bodies is very similiar to the 1970-81 F body. A arms and spindles interchange.

I am not a detective to prove anything. That is fact, Google it or read on corvette forums.

Ask any engine builder they will tell you the same about LS7 block being destroyed from detantion, and re-sleeved aluminum LS blocks having issues with cooling system. Besides the LS7 block all other LSx aluminum blocks are cast around the sleeves. Sleeves have to be machined out in order to press fit the new sleeves. During the process when new sleeves are pressed in the, block cracks (hairline cracks which can not been seen) around the water jackets near the sleeve(s) causes it to leak or pressurize the cooling system. If you are okay with that then go for it, just carry few extra gallons of coolant to add in during fuel stops. :)

By any chance have you worked on or assembled re sleeved none LS7 aluminum block?

LS7 Swap
 

OK.....moving on. As for the suspension, as 77 CA mentioned the A/G cars are very similar to the F-body and do share some components. I do not run a drop spindle on mine, just the QA1 set up. It allows me enough room to reduce the height and can be easily disassembled to change springs if needed. The main concern with drop spindles would be bump steer issues if the suspension does not have enough travel. 6-Grrr, I am going to continue to run the TKO/600. It would be nice to get the 6-speed in the car, but I really dont want to have the expense right now.

I have decided to tackle a another project since the car does not have the drivetrain installed. I have purchased another '73 GA frame from a local wrecking yard. It is perfect and has no rust or previous damage. The reason is I want to increase the frames strength and rigidity. I am delivering the frame to a local chassis shop called No Limit Engineering. They are going to redo all the frame welds, box the entire frame, add cross bracing in specific areas and then true the frame to make sure it's straight. It is as much as I can do without going to an aftermarket frame which I can't afford to do. I will then powder coat the frame as I did with my original frame. This allows me to improve upon my original frame, and then swap everything over all at once. So I will be posting pictures of this entire process as I progress. I am hoping to have the frame finished by November, and the entire LS swap installed before the end of the year.

Thank you guys. I did not know that about the F body suspension parts.

Paul

LS7 Swap into '73 Pro-touring Grand Am Build Thread
 

Just an update on the the GA progress. Part of the build includes re-doing the entire frame. When I originally restored the car, I had done a body off. Frame powder coated and all the rest that goes with it. Unfortunately after that I was always chasing a mild lean towards the driver side. Had a local frame shop check it, and found it to be lower on that side?? Hard to figure why considering the I am the second owner since 1989 and the original owner was 80 years old when he sold it to me. The car never had the lean before I restored it. As luck would have it, I located a 1973 LeMans at a local specialty wrecking yard a few months ago. I decided the best way to approach this was to get the other frame and swap everything over. Last week I pulled it all apart. It took 3.5 hours and none of the bolts stripped or were rusted solid. I know.....we California guys are spoiled. Dont hate me. I decided to take the frame to Rob MacGregor at No Limit Engineering in San Bernardino, Ca. The plan is to have Rob re-weld all the factory welds, box the entire frame, add cross bracing in critical areas, and true the frame. I will powder coat the frame medium/dark gunmetal grey metallic when it's finished. Rob told me they took preliminary measurement of the frame and it was only 1/8” out which he said was very good compared to others he has worked on. He pointed out all of the areas of the frame that need to be improved. He said all of the factory welds on this particular frame were better than most, but will all be re-welded. It would be nice to step up to the plate and buy a custom frame, but I just dont have that kind of money, so this is the best alternative. I did tell him I want to go to a rear coil over set up. I will be bringing him the rear diff next week in order for him to mount it to the frame to get everything squared up for the coil set up. Since I already have a complete Global West front and rear suspension on the car, I will be swapping those parts back to the new frame. ERL called me today. The short block is being machined now, and will be finished by the end of next week. As soon as I know what the piston to deck height is, I am ordering the heads in order to get the compression ratio between 11-11.5:1. I had initially intended on ordering WCCH Brodix castings, but I have recently went to Dr. J's Performance and spoke with Bryce regarding his Air Wolf CNC ported heads. They are very impressive. I received the cam from Geoff at EPS and the MAST oil pan. The cam specs are .633/.640 lift, 226/242 @.050 on a 115 +3 LSA. I inserted a picture of some of the parts I have so far. I will continue to post the entire build as it progresses. Thanks.

LS7 Swap
 

Well I decided to work on the car today. Here is the progress. The two dolly's really help when your doing it by yourself. Now it's off to the rear end shop to have them inspect everything. After that it goes to No Limit for the coil over mock up.

Frame mods finished
 

I went to No Limit Engineering today to see the finished frame modifications. Rob went way over the top and exceeded my expectations. I am very happy with the work. The entire frame was rewelded in addition to the bracing he added. The frame was boxed and then
squared on the rack following all of work to make sure it was true. I had initially intended to do a coil over rear suspension, but decided to stay with the traditional set up and go to an adjustable shock set up. He also built a new transmission crossmember that attatches to the boxed rails. So now I have an an extra trans crossmember for a TKO 5-speed if anyone needs one.