NMNA: Big Block Jagggg

I've seen plenty of 350 Jags but a 454 is a new one for me. I may have to look at it just to take a peek at the other toys in the garage.

https://denver.craigslist.org/cto/d/littleton-1978-jaguar-xjs/7144797670.html

Cue Frenchy in 5... 4... 3...

I saw a really nice clean XJ-S in traffic today. Frenchy would have loved it.

Cooter said:

Cue Frenchy in 5... 4... 3...

This might kill him. Let's hope he doesn't see this. You know a "200hp 454" is an useless swap.

Saved in case the ad gets deleted.



 

It looks good in there.

BBC! It's it's own pun!

I'm going to be driving the recipient of this eventually, when it's safe to visit friends with underlying conditions.

In reply to Floating Doc (Forum Supporter) :

Every man and woman should have a BBC. Here's mine.

In reply to Stampie (FS) :

I had a 73 Cheyenne Super 3/4 ton with a 454. That thing was fun. I never knew what rear end gear it had, but at full throttle it would do about 48 in first, 62 in second, and barely reach 90 flat out.

I have a potential recipient for one, but the 350 in my GMT 400 appears to be practically immortal.

If the engine came out of a Covette or Chevelle SS, it would be worth it.  But out of a motor home, naaaa.  

In reply to spitfirebill :

Why? Compression and cam? Or were there more integral parts built differently?

I'm betting it has more grunt than you think. The motor home block might have forged internals depending on age. Should be north of 300hp and damn near 500 torque as it sits. It's a cam, headers, and intake away from ripping the rear end out of the Jag. Throw a set of heads in to the mix and hold the hell on. 

Toyman01 (Moderately Supportive Dude) said:

I'm betting it has more grunt than you think. The motor home block might have forged internals depending on age. Should be north of 300hp and damn near 500 torque as it sits. It's a cam, headers, and intake away from ripping the rear end out of the Jag. Throw a set of heads in to the mix and hold the hell on. 

Roadkill's Draguar has had plenty of problems with the cooling, engine, and transmission, but no mention of the Jag rearend letting go.  They're running 600-ish hp and slicks.

In reply to Indy "Nub" Guy :

That's because the jag v12's have superb rear ends. 

P3PPY said:

In reply to spitfirebill :

Why? Compression and cam? Or were there more integral parts built differently?

Yes.  But I see Toyman disagrees.  They also aren't 4 bolt mains if that is important (may want to verify that).  

In reply to spitfirebill :

Now I want to pull my RV 454 out of the K30 and see if it has 4 bolt mains.  Or use that as a good excuse to buy a cheap bore scope.

I doubted the torque numbers talked about in this thread so I went looking and found this;

https://www.hotrod.com/articles/bolt-230-horsepower-454ci-motor-home-big-block/

'86 454 motorhome motor, as pulled + open dyno headers = 335hp & 485 lb/ft of torque through the stock q-jet.  I'm surprised.

In reply to spitfirebill :

I dont think the medium truck and motorhome chassis got the same 454 as the light trucks and cars. They were pretty beefy blocks built to turn 3k pluss for days on end hauling heavy loads. Lots of grunt but not a lot of rpms. 

I don't think there was a special "truck block" version of the 454, either, so that doesn't matter like it might with a 366 or 427.

In reply to pres589 (djronnebaum) :

Those mods though. Lawd

In reply to yupididit :

Make you wish you had a built BBC?

Stampie (FS) said:

In reply to yupididit :

Make you wish you had a built BBC?

Got one already 

The 366 and 427 "Tall Deck" engines were used in buses and trucks. As stock, not car worthy, but mix and match some tall deck and BBC parts = big power!! I would need to contact some 1/4 mile friends for more info, but it is available. As to that, one of them has several left over new tall deck blocks he'd prolly sell.

I personally don't know of any motorhomes that came with tall deck engines. May have been a few, but I'll bet most just had low compression small cam BBC's

A BBC Jag wouldn't be my tastes, but a V12 Jag isn't either. Now a jag V12 in something odd...

Toyman01 (Moderately Supportive Dude) said:

I'm betting it has more grunt than you think. The motor home block might have forged internals depending on age. Should be north of 300hp and damn near 500 torque as it sits. It's a cam, headers, and intake away from ripping the rear end out of the Jag. Throw a set of heads in to the mix and hold the hell on. 

I'm sorry to have to repeat this but 454's once they were SAE rated were not the power houses their advertising claimed in the pre SAE standard days.   Advertized or Gross horsepower really took great liberties with reality. 
And it wasn't the "smog stuff"  most of that didn't really hurt power that much once warmed up.    Boat engines ( Mercury Marine) in the 90's put a Chevy 350 only 15 horsepower less  than the 454. They lack any manner of pollution equipment, no Air pumps. No catalytic converter.  Etc. 
  There was a tiny handful of 454's made with  Aluminum blocks,  Forged crankshafts, high compression, Aluminum heads, Solid lifters, Holley double pumpers.  Etc. However all that  ended post 1973  (  More in a minute) 

But that was not unique to Chevy.  Every manufacturer made a relative handful of special engines. GM's Pontiac, Oldsmobile, Buick, and even Cadillac in the 50's and early 60's  did as well  
   As did Ford, Plymouth, Dodge,  and even  AMC.   (Yes Jaguar had their TWR and Lister versions  with hundreds of horsepower over stock. The difference is those were DIN rated ) 
 

Those however aren't what you will find in junkyards.  The growth of the muscle car collect ability made them  carefully sought out and put into collections. At auctions prices they sell at would buy a nice house. 
 What you find in junkyards or for sale today are the ordinary hydraulic camshaft,  cask iron crank, cast Iron heads of no extraordinary merit.

Now and then various manufactures still introduce rare  engines likeChevy's  572.    

pres589 (djronnebaum) said:

I doubted the torque numbers talked about in this thread so I went looking and found this;

https://www.hotrod.com/articles/bolt-230-horsepower-454ci-motor-home-big-block/

'86 454 motorhome motor, as pulled + open dyno headers = 335hp & 485 lb/ft of torque through the stock q-jet.  I'm surprised.

Chevy used the 454 in their 1990 SS454 pickup. 
SAE rated it at  230 hp and 325 ft pounds of torque. 
This article starts out with much higher numbers.   They do admit that instead of cast Iron exhaust manifolds they had a set of headers. Now on a V8 engine because of conflict with exhaust pulses due to the firing order issues headers make a serious improvement.  But maybe not quite as much as claimed?  
What they don't talk about are the correction numbers dialed into the dyno.  No dyno operator corrects their dyno to SAE standards. If they did they'd get few repeat customers. It just wouldn't be good for business.  Editorial; Why do we want to be lied to?  I'm just as guilty as the next guy. But I know a few guys  will "shop around" not for price but the dyno that gives  the most power. End Exitorial    

In reply to frenchyd :

Why do you hate BBC so much?