A happy day, then a sad one (Chevy 350 Conversion)
#41
Join Date: Jul 2012
Location: Walnut Creek, California
Posts: 6,796
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Observations:
1. Noise ain't power, but it can be "pleasant"!!
2. Flat head Ford V8's with differing exhaust systems can sound very nice. Straight out of the headers and hot can sound like ripping silk!
Or a nice ''motorboat burble' from twin glass packs.
3. My son has a very hot Ford 460 in a "Tom's low T". It is thunder and ripping lighting. And, truly shakes the ground like an earth quake.
4. MY aamy
1. Noise ain't power, but it can be "pleasant"!!
2. Flat head Ford V8's with differing exhaust systems can sound very nice. Straight out of the headers and hot can sound like ripping silk!
Or a nice ''motorboat burble' from twin glass packs.
3. My son has a very hot Ford 460 in a "Tom's low T". It is thunder and ripping lighting. And, truly shakes the ground like an earth quake.
4. MY aamy
#42
Join Date: Jan 2012
Location: Newport Beach, California
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ronbros (12-11-2016)
#43
My two cents...
rsmithline,
Love the XJS, she is very beautiful. Always loved this model. Just a quick note on my experience with my Jag conversion. Click the link below or search LS1 Conversion Chapter 1 and you can read about my conversion of an XK8 back in 2013-2014. I will preface this with the fact that since the conversion we have had 3 seasons of driving with zero issues related to the conversion.
Hope you enjoy the read and have success whichever way you decide to go.
Here is the link:
https://www.jaguarforums.com/forum/x...er-1-a-117760/
Love the XJS, she is very beautiful. Always loved this model. Just a quick note on my experience with my Jag conversion. Click the link below or search LS1 Conversion Chapter 1 and you can read about my conversion of an XK8 back in 2013-2014. I will preface this with the fact that since the conversion we have had 3 seasons of driving with zero issues related to the conversion.
Hope you enjoy the read and have success whichever way you decide to go.
Here is the link:
https://www.jaguarforums.com/forum/x...er-1-a-117760/
#44
engine weights
According to this website a L98 350 is 600lbs and a 5.3 V-12 fully dressed for install is 680, where are you trimming 300lbs?? The 350 mid 80's is about 190 hp while the mid 80's V-12 is around 280hp.
According to this website a L98 350 is 600lbs and a 5.3 V-12 fully dressed for install is 680, where are you trimming 300lbs?? The 350 mid 80's is about 190 hp while the mid 80's V-12 is around 280hp.
And that data came from a guy making notes on paper, with no sources for the two weights you mentioned.
Online sources vary on the exact weight of a SB Chevy, BB Chevy, and Jag V12. The August 98 Hot Rod said there was 140 lbs difference between a SB Chevy and a BB Chevy, which is about right based on your chart. But evidence would seem to indicate that the chart's weight of the V12 in relation to the the BB is off, as the companies that specialize in Chevy-into-Jag swaps say "A big block Jag still weighs 100 lbs. less than a 12-cylinder car." (Jaguar Chevy V8 Conversion Kit from John's Cars)
So that makes it about 250 lbs difference between a Chevy SB and the V12. This ad for a lumped XJS says about 230: Weight Loss & Power Gain: LT1 Swapped 1990 Jaguar XJ-S | Bring a Trailer
But when I did my swap I also removed computers, heavy wiring, emission equipment for the V12, etc., and that should also be factored in. (I also swapped in a Chevy plastic/metal radiator for the heavy original brass one). Some folks also use aluminum heads, which saves an additional 50 lbs. Then you can possibly have a weight savings from the different tranny also being swapped in.
So that's where the oft-quoted "300 lbs." difference comes from. Member icsamerica in his post on the prior page said it was closer to 400 lbs., so when all is said and done, even 300 lbs could be conservative. (No way removing just 80 lbs. from the front of the car would make the front end sit several inches higher and require shorter springs, as is necessary in all Chevy SB swaps. And if you sit on your front bumper and the front end lowers by 2-3 inches, you most surely weigh more than 80 lbs. And while a stock 350 may come in at 190hp, it is easily and quite cheaply increased to match the Jag's hp while retaining the weight advantage (nevermind the parts cost/availability advantage).)
I will say this: the "Jaguar" experience to me did not include as a vital component the V12 engine. After all, not all XJ-Ss cam with a V-12. For me, it was the ride/handling (smooth, low, corners on rails, solid as a tank compared to my rattle-y Trans Am), and of course, the styling. These are retained, and with less weight, possibly even enhanced after my swap.
Last edited by Spyhunter2k; 10-20-2016 at 11:29 AM.
#45
Well said spyhunter. Anyone who has done or even seen a swap knows the altitude of the front suspension post swap clearly indicates a major weight reduction. Same thing with 6cyl swaps. Both the AJ and Xk inline sixes weight signifiganly more than a iron sbc.
The XJS or Xj12 or xj6 are better cars with out the added weight of a small elephant high and directly over the front wheels.
As for refinement. I recently did a conversion using custom mount brackets and xk8 fluid filled mounts. Its very smooth and more refined than a typical chevy mount.
The XJS or Xj12 or xj6 are better cars with out the added weight of a small elephant high and directly over the front wheels.
As for refinement. I recently did a conversion using custom mount brackets and xk8 fluid filled mounts. Its very smooth and more refined than a typical chevy mount.
Last edited by icsamerica; 10-21-2016 at 12:43 AM.
#46
#47
I finally bought another XJS. I loved having one of these in college, and it is still gorgeous. I bought this one with 74,000 miles on it:
However, after owning it for one day, it suddenly overheated insanely fast and blew a rod. I choose to take the original owners word for that it was running well when he sold it, and it did run well for me for one day.
I am sad and confused. The car is still gorgeous, but it is simply a 5000 pound paperweight right now. I figure at this point I'm in for a penny, in for a pound, and I am going to do a Chevy 350 conversion to it. I would have much preferred a stock V12 car, but I am where I am right now. I know many will consider it sacrilege, but I have no choice.
Expect many, many questions from me at a go through the conversion process. Hopefully a few here have done one.
My initial thoughts are this:
a John's Conversion Kit: Link
a 500hp fuel injected 6.0 liter Chevy engine: Link
My local shop has done a couple of these already and seem very comfortable with the idea. I found them on this forum. It is Ronnie at Tel Aviv Texaco in Miami.
Any input at this point would be appreciated.
However, after owning it for one day, it suddenly overheated insanely fast and blew a rod. I choose to take the original owners word for that it was running well when he sold it, and it did run well for me for one day.
I am sad and confused. The car is still gorgeous, but it is simply a 5000 pound paperweight right now. I figure at this point I'm in for a penny, in for a pound, and I am going to do a Chevy 350 conversion to it. I would have much preferred a stock V12 car, but I am where I am right now. I know many will consider it sacrilege, but I have no choice.
Expect many, many questions from me at a go through the conversion process. Hopefully a few here have done one.
My initial thoughts are this:
a John's Conversion Kit: Link
a 500hp fuel injected 6.0 liter Chevy engine: Link
My local shop has done a couple of these already and seem very comfortable with the idea. I found them on this forum. It is Ronnie at Tel Aviv Texaco in Miami.
Any input at this point would be appreciated.
#48
Join Date: Jul 2012
Location: Walnut Creek, California
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Wow, the pain of it. And that is a really beautiful car.
Odd, that an overheat would result in a "spun" rod bearing. The "normal" heat related
failures are in the valve train.
I used a kit from Johnscars to lump my 83wuzaa 6. I'm pleased with it. I also considered JTR and Jaguar specialties. Slightly different approaches. But, each
very doable.
I've no issue with the 2.88 in my car. even with the .70 OD, the LT1 pulls it with ease. But, my LT1 is more torque oriented as it's donor was the huge Cadillac Fleetwood Brougham.
Carl
Odd, that an overheat would result in a "spun" rod bearing. The "normal" heat related
failures are in the valve train.
I used a kit from Johnscars to lump my 83wuzaa 6. I'm pleased with it. I also considered JTR and Jaguar specialties. Slightly different approaches. But, each
very doable.
I've no issue with the 2.88 in my car. even with the .70 OD, the LT1 pulls it with ease. But, my LT1 is more torque oriented as it's donor was the huge Cadillac Fleetwood Brougham.
Carl
#49
New rear diff gears is easier than some make it out to be.
https://www.jaguarforums.com/forum/x...upgrade-87356/
Basically 2 ways to accomplish it.
1. Get a center section or a complete IRS from a 94, 95 ,96 XJS. These have 3.54 gears and are a bolt in. These years IRS have outboard brakes too. They are much better in everyway and the absence of inboard brake leaves more room for larger over the axle exhust pipes.
2. Convert your existing Diff. Use a 19 spline Eaton or Auburn locker carrier designed for a dana 44. Use the Dana side bearings and it will bolt in. Then you can use any ring and pinion you want since there are a myriad of choices for a Dana 44.
You will need a spicer flange for a dana 44 to use the jag type drive shaft. If you are getting a new drive shaft then use a standard Dana 44 yoke and have the drive shaft made to match.
#50
I have a 86 XJS with a 1st Gen sbc. I love the car. Great power and reliability. Great access. In fact I've swapped the motor in a weekend by my self, twice.
If I had the money I would have done the LS3 conversion with a better tranny. I had the sb and the T400 so for me it was a done deal.
If I had the money I would have done the LS3 conversion with a better tranny. I had the sb and the T400 so for me it was a done deal.
#51
Jag/Chevy conversion
when you get it done bring it up to Jax, I'll show you my v-12 coupe with a "lack of power" ps, my slow v-12 in impeccable condition is for sale for $5500, a far cry from 12k for a Jaguar with a Chevy transplant which won't sell for a fraction of 12k. Your money, your car....but you did ask for advise. Plus to spend all that money and keep the 3speed trans???? I seriously must be missing something. Plus why even go after a Jaguar v-12 if it suffers from "lack of power". WAY cheaper to go v-12, John's cars quarter breed kit and a different rear ratio.
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