NEED HELP!!- have 4.1 block willl 3.8 heads work??

5 LTR KLR

Member
So I was wonder.... I have a 4.1 block and a set of Champion steel ported 3.8 heads and was wondering will they work on a 4.1 block???


:confused:
 
So there will be no problem with the water jackets???..do to someone posted this in another posted ad:

"Make sure your water ports that are along the lifter valley are correct and everything else should swap over. We did a 4.1 into a Vega wagon and the heads were wrong for the block and it filled the block completely with water when we were ready to fire it up. Your 85 should have a 20 bolt oil pan and the 4.1 will have a 14 bolt. The timing cover and pan will be different in those respects and the 4.1 oil pan won't have an oil baffle in it"


Or anything else I need to do to make these heads fit good???? I want to use Cometic head gaskets and will be using 0.30 TRW pistons as well.
 
The heads should work fine but the cometic gaskets may not. There have been threads pointing out that the center water ports on the block don't always line up properly with the gasket openings. This was the case with my recent 4.1build. One side leaked water into the oil. Switched to FP1200's with a valley tray from AMP and solved the problem. Tolerances can stack against you especially when you start mixing parts from several engines. HTH:)
 
So there will be no problem with the water jackets???..do to someone posted this in another posted ad:

"Make sure your water ports that are along the lifter valley are correct and everything else should swap over. We did a 4.1 into a Vega wagon and the heads were wrong for the block and it filled the block completely with water when we were ready to fire it up. Your 85 should have a 20 bolt oil pan and the 4.1 will have a 14 bolt. The timing cover and pan will be different in those respects and the 4.1 oil pan won't have an oil baffle in it"

Or anything else I need to do to make these heads fit good???? I want to use Cometic head gaskets and will be using 0.30 TRW pistons as well.

The heads are the same castings on production 4.1 and 3.8 engines for any given year. They are not special castings for each displacement. Chances are the info you just posted was operator error. They had a cracked head, block , or a wrong gasket on the engine. Use the large bore gasket and you should be gtg unless you run into the problem powder posted
 
No. We didn't have anything cracked. We had a set of earlier heads or block (can't remember which right now) and where the two water ports are in the 3.8 block the gasket only covered one port and the other was open to the lifter valley. Got the right combo and the car runs fine without water leak. FuzzyGN might be able to remember off hand what the combo was we worked with. Might have been 79 heads with later 84 block but the passages were definitely wrong combination. Hell, it may have been the wrong gasket too. I have slept since then...and had a couple drinks with Dr Frankenstein. :)
 
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