TVR 2500M LS6 Swap

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I purchased a 1973 2500M a few months back to restore. The motor was not original and needed some top end work. I had a thought of just rebuilding it having been a Triumph guy for many years. I also know what it takes to keep these motors running.

Living in Colorado, and enjoying mountain drives, I figured I could use a few more horses than this 2.5L could put out. So I decided to install an engine I had in my garage from another project: a 2001 Corvette Z06 LS6 mated to a 2002 Camaro T56 6 speed. Spec is 405HP/400 ft lbs of torque. By the way, the picture below is not my garage but where the car was stored before purchase.

This forum has been helpful in seeing one or two others install LS motors in earlier TVRs, but I have only seen a few out there with an LSX in a 2500M.

I will be asking lots of questions. Will be posting pics as I go. So here we go. This is what I bought:

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Body has been removed. Remember to lift up the back of the car first and slide backwards before lifting off. These don't lift straight up as the body surrounds the frame upfront near the engine.

Stripped off most of the silvery green. Debating whether to have it soda blasted or using the DA sander to get down to the clear gelcoat. Lots of crazing from being in the sun so I expect I may need to redo the gelcoat. But this is further down the road.

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After removing the body, I set the LS6/T56 in the TVR chassis. I reversed the stock Z06 manifolds for now and the engine is setting on them now. I am waiting on a set of "up and forward" twin turbo headers to arrive to see how they may fit. Twin turbos....likely not needed but they may fit well given the clearance issues between the chassis and any V8.

I had purchased some LSX relocation brackets for a previous C3 Corvette swap and they line the engine mount up to the original factory mount almost exactly. I will be welding in mounts to the front once I get everything set. The T56 tranny mount is very close to the original tranny crossmember location. Sweet! I expect little effort to fab up a mount.

Once I have fabricated the mounts, I am going to need some advice on additional locations for chassis strengthening. I have seen posts where folks say the 2500M chassis is strong enough for most engine swaps. If you have any thoughts on this, let me know please. Otherwise I am pulling the suspension and rear diff, and sending the chassis out for media blasting and powder coating when I am done welding. What rear diff to put in is another question.

Here are some pics.

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TVRMs said:

TVRLS6] What rear diff to put in is another question. [quote said:

Almost finished the build on a 1972/3 3000M with a 331 producing similar numbers.
I converted to a Salisbury diff using the install from the later TVR 3000M.

Think there maybe some easier to get items in Colorado that will do a job for you

is that the same setup used in the Jaguars prior to say 1986? I can find those pretty easily, pne with a LSD, not as easy....but I am looking. Thx.

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Thanks Gents. I have looked at a lot of Steve's posts. Impressive! There is another Pistonhead's user called Catfish that has a similar look and header configuration to what I want to do and is a nice setup. Not sure what motor he is running but it may be a Ford?

But the look I am going for is the 5000M that I am sure a lot of folk's drool over.

I really like the stance.

Edited by TVRLS6 on Tuesday 16th May 23:21

Edited by TVRLS6 on Wednesday 17th May 01:56

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Arthur.

That is one sweet build! I am using yours as a go by for mine but with the LS6. I like how you routed the exhaust. Superb job on the entire car. Looks super professional.

Did you powdercoat or paint the chassis? Looks awesome.

How does it run? Are you satisfied with the performance and handling?

Tons of questions.

Ty

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catfishdb said:

Hi Ty,

It is still a work in progress. I drive it as much as I can. Gives me a time figure out what to do next.
I want to keep it as original as possible on the exterior but there might be subtle changes.

I had the frame zinc coated, then powder coated in a gun metal grey. Your frame looks to be in solid shape other than what appears to be surface rust. There were a few adjustments made to the frame before it was powder coated. The handbrake lever was replaced in an attempt to get a bit more holding power on the lever. There were an additional set of tubes welded in where the frame widens to accept the transmission/motor. And gussets were added to some of the suspension pick-up points. The square tube in front of engine was modified to accept the pulley assembly.
I also had the hood hinge assembly altered and now have a fully vertically opening hood.

The image above shows an earlier radiator. It ran a bit hot with the second V8 so it has been uprated to larger fans and a larger aluminum radiator. The manifolds were ceramic coated to keep the heat in the engine compartment down but you will soon realize the heat has to go somewhere. So it pushes it thru to the tunnel. The car gets a bit warm in the summer.

It has Bilstein coils and shocks. I will change the coils to something a bit softer. The present setup is a bit harsh and twitchy on rough surfaces.

It is an absolute hoot to drive. Loud, really quick. Difficult to get the power down, but get it right and let the power build and you are in for a ride.

Arthur

Well I really like what you have done to it. If I get close to what you have done in terms of quality and workmanship I will be happy.

The chassis on mine needs a good bead blasting Just surface rust. It was a Texas car from what I have been told so in good shape. Then it is off for powdercoating.

The right front hinge points for the lower wishbone are bent back so the previous owner must have hit a big pothole or ? I will be bending back and adding gussets there and few other places on both sides.

It looks like my front pulley will fit fine and I don't see other areas I need to widen or change to get the motor in. But I just got the up and forward turbo headers I ordered in today and will put on to check. I am hoping I don't have to custom build a set. I won't heat wrap the headers. In my racing days I have seen headers nearly melt with the wrap on. Ceramic coating definitely helps and I will get that done for sure. Had that done on a TR4 I raced and it was incredible how it reduced the underhood temps.

Getting the heat out seems like a challenge. I am going to overdue it on heat and noice insulation, but it has to go somewhere like you said. Have a few ideas I will run past you as I experiment.

Do you know what your spring rates are? Like you, I don't want something too tight and twitchy. Great for the track In a controlled setting, but not good for bad roads and potholes.

Thx for sharing

Ty

Edited by TVRLS6 on Saturday 20th May 14:55

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Agree on not cutting the upper tube. I thought I may be able to reroute the stress to another point. But the I had my son come over and we lifted the motor a bit higher, moved it forward a few inches more, and still maintained around a 3 degree tilt to the rear.

This solves the header clearance issue and they will work fine. I will likely do what you did with the front cross tube and give my crank pulley a little more clearance.

We then put the body and hood back on to check clearances and all fits well!

I need to order an alternator relocation bracket to check on any issues for it to clear. Otherwise i will be pulling everything off, gusseting the points I see on yours (thanks) and getting a beefier rear end installed.

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Okay, I am looking at Jaguar rear ends. I read that all the XJ12s had 331 posies. Trying to fnd one wher I live is a whole different matter. Am I looking for the right one? Are there other diffs I should consider?

I see a lot of BMW IRS diffs and the R200 in the Datsuns is another I am familiar with. The Jag looks the easiest to install as the mounting brackets are known given the Salisbury came stock in later models.

And should I just grab the carrier or do I need the half shafts as well? Any help on what others have done that will handle 400HP is appreciated.

Thx

Ty

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The chassis has some surface rust, but good otherwise. Was a TX car. Will be gusseting and strengthening it and then it is off to the blaster for cleanup before powdercoating.

The rear diff from a TR6 is the weak link. Need to figure out what to do their and fabricate the differential mounts before chassis is blasted and prepped.

Thx for the advice.

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catfishdb said:

The next pieces to break will be the half shafts if you really work at it. The car is relatively light so it is difficult to get the power down without wheel spin. I have seen another 5000M that broke the half shafts so when it was repaired he replaced the broken shafts that had grease nipples to a version without the grease nipples. The theory being that the gallery for the distribution of grease was slightly weaker than the shafts without the grease nipples.

Arthur

Thx Arthur. Were you able to reuse the TR6 half shafts or did you use the half shafts that came with the 4HU?

I am also wondering if the GoodParts.com half shafts may work. They are much beefier but I don't know if they could take the HP we are talking about. I have a few guys run these in their TR4A and TR6 IRS setups when I raced in vintage.

Thx again

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TVRMs]Couple of 4HU installs said:

Nicely done. Looking at your profile, you have done a few of these! Do you powdercoat or paint your frames? Also I like how you reworked the the cross brace in front of the engine. I may need to go that way to get my accessories to fit.

Thx for sharing.

Ty

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Arthur's car and yours are good references for me certainly. Thx to you both for sharing.

In terms of rear differentials, I am expanding my search beyond the 4HUs. Looking at the Infinity G37/Nissan 370Z diffs as they are similar in setup to the Triumph TR6 diff and rated at about 350 hp. They are plentiful, comparatively cheap to buy and there are lots of parts suppliers. I can easily go to CV Joints on the inboard side and then modify the outboards (maybe) to the hub. Still researching.

Also looking at the newer Camaro and Mustang IRS setups for the same reasons. Will let you know what I find out.

Ty

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ephemera said:

Thank you for the kind words. I also don't want to hijack this interesting thread, so I'll keep it short: it was a wonderful time building it, but due to other commitments it is only just run in, and actually your post pushed me to give it the full beans today for the first time, and now I can honestly say it is also wonderful driving it. Awesome performance as you might expect, very driveable due to not go too hot on the cam, which I am really happy with, and still revs without any problems, but greatest surprise for me is that it feels so tight, no rattles, and it is very confidence inspiring, the balance is actually much better that I dared to hope. Which is nice when there is a stonking large V8 up front in our much loved Vixens. I am considering taking it to Zolder Continental Meeting this month. Everyone keep up the good work and impressive builds guys!

Great work on this build!

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Picked up a Nissan 300ZX twin turbo LSD differential locally with 3.69 gears. I don't think I will use 6th gear that much, but I can always go to lower gears. The price was right.

Goodpart.com has heavy duty half shafts and hubs that will make the swap easy. Just need to get a Camaro driveline end shortened and changed up to mate to the input shaft on the 300zx diff. Need to fab the rear diff mount to the frame and will be good to go.

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griff 200 said:

Fitting that power and toque to the chassis is one thing but think about using a more modern TVR rolling chassis that has stronger less rusty tubes plus both fount and rear uprights and brakes can take the upgrade wheel base is the same and fits to the m body without massive mods this will be a lot cheaper to do that build it all up out of parts from different cars and try and make it work.

Finding another newer chassis may be easy to do in the UK, but not in the US. Good idea but then there is reality. Ths frame is dirty, but not rusty, and will be reinforced. And there are plenty of guys with 300+hp TVRs. This will be 405HP at the crank, and not a dragster....

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jellison said:

This seems like a CRAZY thing to do!

Nope.
Just a 5000M with a little more punch...AC Cobra killer is the goal.