fleming23

Before anyone says to do a search, I want to assure you that I have a number of very helpful threads saved and have been using as a resource.

I am getting my parts list together to do a GMPP LS3 swap into my 71 Coupe and would value any (helpful) opinions and ideas about what you know worked or didn't. Many of the threads I found start off in one direction and 10 pages later end somewhere else so it isn't always clear.

Some of the main threads I am using to get ideas/visuals.

http://forums.corvetteforum.com/c3-t...o-my-72-a.html

http://www.digitalcorvettes.com/foru...d.php?t=161408



Basically I am planning to use the Chevrolet Performance LS3 525HP Crate engine 19301360.



I know this motor is about $1000 more than the 480 hp version but I like everything I see and believe the ASA cam (226/236 .525/.525) will sound right at home. My only concern, and one I haven't researched yet, it having adequate vacuum to power the brakes & run the lights, etc. I have a 70 Chevelle with a 496 BBC with a 107 LSA cam so I know about low vacuum but this ASA is on a 110 so I am hoping it will be adequate. I also know it would probably be cheaper to obtain an LS1 or 2 pull out and build my own but this is the route I wish to take.

I will use the 98/02 Camaro LS1 oil pan kit as I believe that will clear all the stock steering parts (Borgeson box on this car.)



I am debating whether I need/should use the recommended GM Engine Controller Kit or call Speartech as they seem to come so highly recommended for these swaps. I don't know if I gain anything one way versus the other.

This is the engine controller recommended by GM
GM Performance 19259261


I probably plan to use the Kwik Corvette LSx A/C & Alternator/PS Brackets as they seem to work from what I can tell.

I also have the Metric Adapter/Electric Temp sender adapter included so I can retain the factory sender.

The car currently has a 400 trans and I have a 4L80e that I am getting ready to pull out of my Chevelle that could take the 400's place with a stand-alone controller - or alternatively if I use Speartech I suppose having the trans integrated into the ECM might make more sense. Just not sure if I want to try to get the motor bolted to the 400 and get it all working or go ahead and use the 4L80....probably will use the 4L80 because it is coming out regardless and is a built trans from Jake's Performance.

I currently have a Dewitt Aluminum radiator but may try to sell that to buy the LSx radiator with steam tube and electric fans just so plumbing is easier. I have read that the waterpump requires modification but it appears that just involves using some 45 or 90 fittings to connect the heater lines along with a 180 degree/straight thermostat housing - maybe I am missing something here.

I ordered a new fuel tank with an F-body pump from Vetteworks and will use this with a newer fuel filter/regulator to handle my fuel demands.

Other than a set of adjustable mounts, what else am I forgetting??? I plan to retain the factory booster unless it just absolutely will not fit at which point I'll give Hydratech a call. I have seen conversions with the booster in place but then read where it will not clear something. I also plan to retain the factory A/C box, assuming it clears everything, and use a Sanden compressor since everything currently works.

Edit: Also not sure what I am doing about exhaust at the moment. I am not looking forward to long-tubes just because regardless of how tight they tuck up to the body, they still have a tendency to scrape around here. My initial plan is to use the exhaust manifolds that seem to come with the motor but would certainly be open to ideas of maybe a mid-length that clears everything with no issues. Exhaust will exit out the rear. I already have the 2 1/2" Magnaflow mufflers in place. Just need to finish the mid-pipes.

Jay71

Sounds like a great plan ... I can't wait to see it finished !

Garys 68

While the factory ecu will control the motor, I'm not sure a stock tune will work. Plan on budgeting for a tune.
Standalone 4L80 controlers are expensive. You'll probably need a custom harness and tune to run the LS3 with GM ecu, again expensive. But go for the OD trans. You will only need to add a VSS if you do keep the TH400.
Check out the new holley brackets, cast, look like stock GM stuff, price is great.
Water pump is simple mod. Remove heater fittings, NPT tap.
It will clear the factory booster.
02 Factory vette exhaust flows really well.
http://www.carcraft.com/techarticles...e_header_test/
The oil pressure sender adapts to 1/8" NPT, that should fit your sender.
The temp adapter goes down to 1/8 or 1/4" NPT. My 68 sender is 1/2" NPT. You can drill and tap the drivers side threaded block plug easily for 1/2" NPT.

74modified

Sounds like a pretty good plan.
Good Luck!
Be sure to use a LS thermostat with the straight housing, not a small block thermo.

fleming23

GM says this ECM & Harness are specifically for this motor so my assumption is that it will be more-or-less, plug & play assuming no other changes.

I already have the 4L80 stand alone controller so no expense there.

The speed shop I use just used the Holley alternator bracket on a 69 Camaro LQ9 swap, just wasn't 100% sure they would work on a 71 Vette. If you can confirm they do work, I'll certainly consider those as they may be just a little cheaper and do seem to work well.

Thanks for the other comments as well! I'll make notes about the WP and senders.

Garys 68

Donnie over at Vettmod just put the holley in a 74. I think both the Holley and Kwik have the pulley interference issue with the upper control arm and limited pulley selection due to the vette PS pump shaft diameter.
If you have the controller, go for the 4L80!!!! What's your rear end ratio?

Vettegineer

I'm doing this right now, and Gary68 hit most of my notes! Really go look at the Holley mounts--i used their AC unit-- then bought GMPP non-AC front accessory kit. I sanded them down removing casting marks, and now getting them powder coated. I got a good deal on the GM starter--and Camaro heat shield--get the second "long bolt" with the starter.

I bought the gmpp controller, but bought the TCI EZ TCU--eBay best price. I did measurements, and couldn't see the 4L80 fitting--it has been done, but be ready to mod the tunnel. I built a 4L60 into a beast with the help of a ASE Tranny guy turned mechanical engineer--we will see if it holds. I went with the S7--seems like the S5 is slightly less output then our stock AC--also changing to parallel flow condenser.

Steam tube is over rated--tapped a hole in the water pump, and it looks good (not running yet--still on the stand!)

Control arms turned into a big deal. Rubbers shot, rebuild required...now more project--parts are here.

Changing to C4 squirrel cage out for more air flow from fan--another big time adder.

That's all that comes to mind! Read GordonM and Riggs install threads--I learned a lot from them!

Les

fleming23

Thanks to both of you!

I believe the rear is probably a 3.08 based on cruising RPM but I'll most likely change that to a 3.73 if I do install the 4l80. Fitment is my biggest fear as it is a beast and barely fits my Chevelle tunnel.

I was hoping one of the alternator/PS brackets would clear the control arm without any drama but it doesn't look like I'll be that lucky. I know one of the threads I was reading mentioned swapping pulleys to a smaller Dorman so I'll have to see what worked. I'll definitely use the larger Sanden compressor because I need as much cooling capacity as I can get.

Garys 68

The chevelle tunnel is actually smaller...or at least the one on my 72 442 was. You might need to move the engine/trans mounting surface forward with the 4L80, but check out the 4L80, non-LS swap info on C3s.
Wait before you swap out the rear, an auto with 3.08 might be ok.

fleming23

That is very good news on the tunnel!

I will be waiting on the rear gear but I know in the Chevelle I don't get into 4th with a 3.73 until around 55. With the controller I can change the shift points to whatever I need them to be so not too worried. I was more concerned about tunnel clearance.

Gordonm

That one thread is mine. The PS pump pulley is to big. I swapped over to a different pulley I think I posted the part number and it is tight but clearance is ok. Since the motor torques away from that side it should not be an issue. My LS swap has been on hold for a year now due to personal reasons but hope to get back to it soon.

holley505

Gents I have a LS3 in my 77 Vette.

LOVE IT...

I use a F-body oil pan...

I did have to put spacers in the Steering to make it clear...

I do use a TH400 with a 3500 stall

and Finally... No Computer or wiring harness here... just a SIMPLE plug and Play MSD BOX. http://www.jegs.com/i/MSD/121/6010/1...FZFr7Aod6nMA0Q

Oh yeah... its got HOLLEY DOUBLE PUMPER...

Garys 68

Mine has a Richmond 6 speed, but the one issue you might have is with driveline angles. The bigger yoke and trans requires the back of the trans to be down. The original vette angles were nearly 0 degrees all the way around. I ended up with the engine/trans down 2-3 degrees and the differential in the stock 0 degree position. I trimmed the front rubber diff mount to get the pinion angle up as high as possible and raised the rear of the trans as high as possible to get equal angles.

Bagmup

Sounds like a bloody awesome plan, subbed this thread.

70LQ4

I'll buy that DeWitts Radiator, and I have a new straight Thermostat housing with T-stat that I bought from Street and Peformance to work in on the deal. I went a different direction and don't need it. Check into the bat wing Oil pan it will fit great with the Borgeson steering box. MSD makes a Engine control unit that replaces the fuel rails (Atomic 2950) cleanest set up I have ever saw. See it here: http://ls1tech.com/forums/new-produc...-sk-speed.html

fleming23

Sounds good. It might be a couple months as I get everything in line.

ignatz

If you have the Borgeson you don't need to swap out the pan

fleming23

Thanks! I actually realized/discovered that earlier today.

fleming23

Well, tonight I did some ordering!!!

I have the 525 hp LS3 coming this way. I came very close to ordering a 427 from Texas-Speed but after two phone calls to them I did not have a very good feeling and still don't have the quote I asked for. I understand companies being busy but for someone ready and willing to drop $15k, I expect a friendly voice on the other end of the phone, patiently answering my questions no matter how redundant.

Here is my order with Pace Performance.
LS3 525 HP - $7,458.88
GMPP Accessory Drive without A/C - $509.95
Corvette LS Top Mount A/C Compressor Package - $469.95
Powermaster Powermax LS Starter - $184.95

Ordered a(nother) new radiator from DeWitts for the LS with dual SPAL fans - $1045.00 shipped.

Custom Harness from Speartech with ECM & TCM - I believe approximately $1600

Autometer Sport Comp 7 gauge package from Jody @ VetteAid (added wideband Air/Fuel) - little over $1000 (maybe closer to $1200 when all was said and done.)

I still need to get motor mount plates but will probably get those from VetteAid unless I can see some reason why I NEED adjustable plates like the Dirty Dingo plates.

I debated doing Melrose long-tubes but after seeing mixed comments/reviews I believe I will either keep the factory manifold or most likely, plan b, do the Sanderson LS134 block hugger headers. Pretty cheap and looks like they will eliminate some of the issues commonly faced with long-tubes.

Before I can get started I need to do the auto to manual conversion in my Chevelle so I can get the 4L80 out for this swap.

I can't wait to get this project going! Debating on whether the vintage air is in any way an upgrade over the stock right now. The factory air works but suffers the common leaks that these 40 year old systems experience. It would seem the sealed vintage air system would eliminate many of those problems along with clearing up/cleaning up the firewall and engine bay. Verdict is still out but if anyone is reading, I certainly would love some first-hand experience. I plan to put the computer and relays behind the passenger dash so I am also concerned the vintage air system would consume what little bit of real-estate we have back there.

CWerner

Do the VA. I am with my swap. It really cleans up the engine bay nicely. I had the same debate on my swap. Even though I haven't run it yet, the clear advise was to do it.

I've got a thread running on my swap on the C3 general. Very similar swap.