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Old September 1st, 2012, 23:21
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alex22 alex22 is offline
NAXJA Forum User
Join Date: Oct 2007
Location: CT: waterbury area
Posts: 1,434
Re: Performance 4.0 build

I finished up an engine for my cousin a few weeks ago so its back onto my own.

My cousin's:
Dart block, Eagle 427 stroker crank and rods, Mahle pistons, ported heads with dual 450 carbs, solid flat tappet and 10.3:1 compression. 537 Hp @ 5500 and 548 ft*lbs @ 4600.

My 4.0 so far:
0331 head, the top of the head was not cracked between #3 and #4, but...

Replacement head from ATD Diesel, new casting.

Gave it a performance valve job.

Intakes and exhausts cut.

Always check concintricity.

Placement of the seat to the valve. The intakes were backcut to 34* and 19* and the exhaust valves to 30* (forgot the pics of those.)

The ports and chambers were a bit rough and I spent a few hours with the die grinder. I flowed it and compared it to a factory 0331 head with only 7000 miles on it which came through the shop a few years ago. I flowed that one on my own time just to see how it was. This head now flows about 10 CFM better than the factory head.

Head on the bench, I forgot to print out a report though.

Now onto the block....

After a quick hone I did a test fit with all of the pistons to determine how much to deck it. Now on the resurfacer, I took about .025 off the block to put the pistons between .010 and .005 in the hole. I had to cut .005 off of the deck just to clean it up, the shiny parts in this pic are the areas that the cutter hit first.

All finished up in the hone.

And how it sits as of now. Rods maged, ARP rod bolts, resized, weight matched and balanced, checked for straightness, hung the new pistons, checked piston ring end gap, align honed, clearances checked final cleaned and painted.

Its almost too pretty to put back into the XJ

And now that I'm back in school Its going to be slow going for this 4.0

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