Some good ideas there. There is a rather large casim between the front of the engine and radiator setup so im considering a relocation of the radiator back 3 inches and laid down 5 degrees so i can install an X brace on the radiator support for chassis rigitity. That will also allow a nice air scoop to be fabricated in the space the existing rad support occupies now.

I considered going back to a 2.88 from the 3.54 i have now. The present engine makes so much torque 1st gear its totally useless. Accelleration G force data suggest if i can spend more time in 1st and 2nd gear the car will be quicker. So i found a 3.06 power lock from a v12 Aston Martin and may give it a try. It would lower my 70mph RPM to about 1800 and that would help the the sedate cruiser aspect of this project be more mellow and should make the car quicker because 1st Gear might be useable at more than 1/2 throttle.

Another angle would be to use a larger camshaft which would cut down on low rpm torque and raise power at a higher rpms. This probably would make the car quicker but this could compromise idle quality.

In any case the goal is high 11's in the 1/4 mile with a dead smooth idle. Im gonna try the 3.06 diff first as the engine is tuned close to ideal.

 

With stock OD tires, 2:88 and 200R OD ratio - my car turns 1700 RPM at 70 MPH... started with ZZ4 383 short block, added Comp cam 270HR, Crane 1.6 rockers and Edelbrock 64 CC heads. Pretty smooth 700 RPM idle... plenty of low end torque. Much nicer now with the modern TBI system...around 350 HP at the rear wheels.

If I was doing a engine today, I would put in a LS7 or LS9 (if it would fit under the stock hood?) and the modern six speed automatic...

It was not built to be a race car but to perform well and be a good street car... the SWB allows it to handle like a sports car (might as well be a coupe since there is no rear leg room).

 

icsamerica,, the 1976/1979 XJS had 3.07 Powerlok!

 

That's an amazing car, icsamerica! Did you do this all in New York City? Do you have your own space and set-up or are you working with a specialist?

 

Thanks. I really enjoy driving and working on the car. Still many changes inprovements and more power with smoothness to come.

Well I'm in Staten Island, That is technically in NYC. I have a 2 car garage attached to my house. Nothing special about it except that in this area like the rest of NYC real estate prices have spiked recently. It's getting silly and toppy. One of neighbors is asking 1.2 mil and there's another round the block asking 1.6 mil.

I just do the best I can with the space and time I have. Its difficult and when I retire I plan to have a huge garage somewhere. That will make things easier and my projects better.

As for the specialist...that's me. My interests are an inch wide and mile deep. I'm over focused on XJ Coupe's and by association the XJS

I do love NYC though, born and grew up in Brooklyn in the 80's and I still work in all the other 4 boughs weekly. Recently spent a few days in South Florida, It's another world down there. Nice but not for me right now.

I see you're from NYC. As you know NYC is diverse and there are MANY great Jaguar guys here and in this area too.

Have you seen this?
https://www.jaguarforums.com/forum/u...3/#post1662848

 

I made a new air box. I learned that the air cleaner I had on the car was only good for about 300 CFM. That's not enough for my application so after much searching I found a very large air filter that is over 100 square inches and was proven and tested to flowe over 570 CFM. The problem was making it fit.

I initially tried to apply the same techniques as other who have used a large and flat cone type filter. I deemed this insufficient for my application becasue when installed in the vehicle the clearance is extremely close to the radiator on the bottom very close to the hood on the top side. This probably would greatly reduce the the air cleaner flow capacity. It's looks slick and clean but wont flow.

Here is my take...

intake box with no plenum tube and no air cleaner.


Complete and all buttoned up.

So how does it work. Very well... On my spirited drive I noticed the high RPM AFR's went as high as 14.0 at the top of the RPM range. This is unusually as I had the car tuned and they used to be in the low 13's and would spike to high 12's at the top of the RPM range. This suggests more air flow and that's what I was after.

There were 2 other side effects that are quite desirable for me. The engine noise inside the cabin is greatly reduced with this intake setup. The other knock on effect was the car felt more solid and I detected much less steering column twitch when traveling over rough road surfaces. The air box is made from sheet metal and its quite rigid and I can only surmise that it solidified the frame a bit.

 

Got the car lower and handling better. I traded in the OE rear springs for some off-the-shelf Eibachs.

The Eibachs are 10 in free length 250Lb/in and the OE springs are about 11 inch and 230lb/in. The Eibach's are 1 inch shorter but 20Lb/in stiffer. My calculations suggested with the fulcrum effect that this would give me the 1.5 inch drop I needed for the car to sit and look right. I was planning to make an adjustable lower spring retainer but figured I'd try them right out of the box and they're fine as is. Simple is good.

This setup offers up the right ride height for my tastes and local roads. There is also noticeable increase in handling performance. However I detect no decrease in comfort or any additional harshness. Rear end feels less wavy or flighty. It's astonishing how much power you can put through these cars and they remain controllable with just minor upgrades.

This also made hard launches much easier. I'm guessing with a lower rear suspension I get more weight transfer and better grip. Cant wait to run the 1/4 mile next week.

If anyone wants to give this simple and low cost approach a try....the part number for the springs can be seen in the pictures. If was I going for even more performance I'd run the 300lb/inc Eibachs in the same line.

I daily drive this car around the 5 boroughs of NYC. It's comfortable, easy to drive and downright fun. The amount of people who stop me and ask about the car is something I didnt expect. From guys in new Jaguars to Toyota beaters and everything in between, amoungst the young and old there is broad appeal for this unusual classic.

 

Just Beautiful!!
You must be proud of it and have every right to be so.

 

DITTO, IN SPADES !!!!!


Carl

 

these would also fit over the kyb spring perches ???

 

Very Nice!!
It sits a little tall for my taste, but I realize we're dealing with subjective preferences and local road conditions. I doubt Nix could successfully navigate some New York streets without tearing out the whole undercarriage.

But again, Very Nice!
(';')

 

I am a new Owner of a 1976 XJC. Thank you for your time and effort in documenting your many upgrades. I'm going to read it all again now!

Rusty

 

That's my favourite stance for an XJ6. It emphasises the crouching cat look, which is what first attracted me to the car, way back in 1968.
For me, cruising the five boroughs in a car like that would be a major tick off my bucket list. So you can understand my level of envy that you get to do it on a daily basis. But I'm not one of those blighted fools who hate the object of their envy, & it actually warms my heart to know that someone somewhere is living that dream. & with the skills you've shown to get the car sorted, I'm very glad that it's you who's living it. You've earned it!

 

Wow thanks. It's appreciated that you took the time to write that.

 

Is your XJ6C rusty or is that just you? Any picts... Ya know philly isnt so far from NYC, keep me in mind if you're ever up this way. I love coups.

 

My Mom called Me Rusty instead of Russell
I took a Gamble on this Car from Utah. Turns Out the Car is 100% solid No rust But needs Everything else It has a 350 in it But I'm hunting for XJR6s with Getrag. So I can cruise on up To NY area! I'm Sure once I get rollin Ill be on Here often.

 

Nice ride Rusty. Mechanicals are easy to fix, though not always cheap. A rust free body is the really hard gem to find, & yours looks like a beauty! I can't wait to see what you do with it.

 

Yes, I think so. The Eiback springs are 3 inch ID, slightly larger that the OE springs, I'd say about 1/8 of an inch. With the Bilsteins I was able to tweek the tabs on the upper spring retainer for a perfect fit.

 

[QUOTE=Rustyxjc;1695758]My Mom called Me Rusty instead of Russell
I took a Gamble on this Car from Utah. Turns Out the Car is 100% solid No rust But needs Everything else It has a 350 in it But I'm hunting for XJR6s with Getrag. So I can cruise on up To NY area! I'm Sure once I get rollin Ill be on Here often.


Oh.... This project.

https://www.jaguarforums.com/forum/p...mplete-170791/

Seems like a good buy to me. Knowing what I know about coupes, you couldnt get there for the price you paid.

The 350/700r4 combo is a pretty good setup but I can understand the intrigue from a XJR/Getrag swap. I was considering it but will probably go LT1/T56.

 

Wrapping this project up. It's not perfect but good enough. There are so many upgrades that worked out very well and a few things I would do differently.

There are also quite a few cosmetic details that need to be addressed on the interior. Still have to fashion some covers for the foot well corners. The OE ones will not work becasue there is lots of XJS wiring harness that will just not fit under the OE panels.

Got it polished and waxed it with the help of my 10 year old daughter. That was nice.

I spent many hours flattening the panels. I've worked on Many coups over the years and all the panels are all very wavy. Between the wavy panels, unfinished roof, panel gaps, weather stripping, myriad of chrome finishers...These are difficult cars to make look right.

So the blue coupe is next. Been hemming and hawing over the motorvation... I thinks it's going to be a LS engine with a 6 speed T56. Taken to the next level, every thing I learned from this car and more. Will dial back on the straight line performance though and make it more of a cruiser becasue the Blue coupe is rust free and I don't want to cut up the rear wheel wells. Doing it the way I did it is also a TREMENDOUS amount of work.

Finally got a good camera.





Widened wheel arches look OE and keep with the lines of the car.







The whole back of the car even up past the body crease was pie cut, widened and welded up.



Flattened for days



Dash and ski slope finished to match



Lots of one off and XJS parts in this project.