Chevy VS Jaguar V12

Not off the top of my head but it’s really heavy!!,there are ways to lighten it but easier and almost cheaper is use Chevy racing Con Rods.  Then you can offset grind the crank and gain almost 1/2” stroke. Which will of course mean custom pistons, then you may as well bore the sleeves out at the same time. 

Then port the heads, go big valves, and bigger cam shafts.  Rework the intake manifolds to use the 4.0 Six intakes on both sides. And you are approaching 500 horsepower, now a pair of T4 turbo’s.  And you’re at 1000 hp 

Of course you’ll have spent $20,000 or more  by the time it’s installed and running.  And requires some really good gas, the kind they don’t sell at gas stations. 

Just running around you won’t feel more powerful than a rebuilt stock $500  motor with a pair of $128 T3 turbo’s  but racing you’ll have twice as much power pulling you down the straight. 

In reply to frenchyd :

I read in an earlier post that you had a lathe.  What size?  

In reply to MARKUSA :

If I may ask?

In reply to MARKUSA  

I sold my big tool room lathe  now I have just a little benchtop  Atlas lathe that’s really only suitable for making small pieces

In reply to frenchyd :

What size was your tool lathe....the one you turned liners on?

In reply to MARKUSA :

It was aGrizzly tool room lathe. 16”x40” if I remember properly. But any lathe that could grip the sleeve ( about 4 inches )   By about 6 inches long  

You could also bore it out on a vertical mill. 

In reply to frenchyd :

Hi again,  You recommended dumping the V12 butterfly assemblies for the 4.0.  Are they bigger?  Do you know the mm size 5.3-6.0 vs 4.0?

In reply to MARKUSA :

Sorry I’m slow to respond, insanely busy and the few moments I had I forgot my password!  

Anyway I don’t remember the difference in sizes and I’m such a Luddite I’d remember them in inches.  

Anyway the V12 intake(s) flow 1200 CFM so 600 CFM each. Thus each one feeds 2650 cc. For a total  of 5.3 liters ( yes the 6.0 liter uses the same size) 

the 4.0 flows 850 CFM through one, so two will flow 1700 CFM.  

Now what is your goal?  Stock is more than fine!  It will support up to 450 horsepower!   However if you are like me and an all out racer seeking maximum horsepower for the lowest cost you’ll go to the 4.0 intake in combination with cams, pistons, and a pair of T3 turbo chargers using bigger injectors and burning E85 to push those numbers way past that.  

In reply to frenchyd :

I plan to use two T3 or T3/4 turbos but never will be raced but want a bunch of HP anyway...just a weekender for me and my wife.  So in my case I think the stock ones will be fine.  THANKS

Hi again, Anyone know the block heights of the 5.3 and 6.0?

In reply to MARKUSA :

They are both the same 

how would you like it measured?  Crank pin center to deck? Oil pan to top corner of deck? Bottom of pan to top of manifold? I don’t have any aluminum pans left to measure the depth difference but assume adds an inch. 

Crank pin center to deck

Are all oil pans the same dimensions but different materials?

In reply to MARKUSA : 9&1/2 inches  

In reply to frenchyd :

THANKS

In reply to MARKUSA :

Aluminum oil pan was only used on the XKE V12 

i think it’s about 1 inch deeper, Dont have one left to check. 

In reply to frenchyd :

Do you have the combustion chamber cc on 6.0 head?

In reply to MARKUSA :

No I don’t keep them.  The compression ratio goes down from 11.5-1 on a 5.3 to 11.0-1 on the 6.0  but the shrouded valves kill all the power. 

In reply to frenchyd :

Is the power loss considerable?  Can they be unshrouded?  Would the lean burn setup be good for a boosted engine?

In reply to MARKUSA : The peak power available from a all out race only HE head is 450 hp.  

The Flathead is capable of 750 reliable horsepower before boost.  

Unshrouding the valves would lower compression down which would decrease power. 

Under boost you need to go richer not lean things out. Lean + boost= Bang!!!! Junk created.  

In reply to frenchyd :

How important is the forged crank in the boosted 750hp range?

Sintered Iron has been proved reliable up to 500 hp,  I don’t know of any documented case where it has failed but frankly I’d be uncomfortable at 750 hp. 

The first years production of the 6.0 were all forged and they went into cars as late as early 94 but I don’t know the cut off. 

Realize  that 750 hp is race only territory. While you could possibly get to 750 hp boosted and have it semi streetable  getting to those numbers would require a lot of development.