360 LA installing Promaxx Aluminum heads

74Scooter

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Finally got the top end off my 360 and am preparing to install the Promaxx heads that I've been lugging around for over a year.

I'm sure more questions will come up but first out of the gate is spark plugs. I've been using E3's (E3.46) which has 13/16 hex, .750 reach. The 13/16 hex is not going to fly with the new head. Can anyone confirm the E3.58 is a suitable replacement? It's 5/8 hex, .750 reach. Insulator is slightly shorter. No clearance issues at all with my TTI shorty's.

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MOPAROFFICIAL

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Just order a set of plugs for a magnum engine, 5/8 version of an LA plug essentially.
 

74Scooter

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Is it just me or is there something really satisfying about cleaning piston tops? Going to need to power wash the engine compartment after it's all back together. Almost ready to start installing the new heads. :)

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74Scooter

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Looks good. What was your weapon of choice?

I started soaking them with Zep 505. Then hit again with Zep and a scotch brite pad. The tough stuff got the brass/wire wheel treatment followed by Zep and the pad. Then I hit the outside of the cylinders with the shop vac to try to keep the gyrotis from getting past the upper ring and/or into the pan. I'll be swapping oil after I get it running anyway, let it run long enough to hopefully let the filter catch whatever made it into the oil system.
 

74Scooter

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Just tried test fit of new head. First one out of the box will not settle on alignment pins on either side of the block. Holes look good (did not mic yet) and they have a slight taper at the opening. Feels like it lines up, just won't settle flatly on the deck. One pin goes in and the other seems to sit on the top of the hole. Have not tried any force at all.. just the weight of the head itself. Is it typical to have to pull the head onto the block evenly with the bolts or maybe persuade it with a dead blow mallet??
 

Bobzilla

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Do not force it into place. This is common. Use a head gasket to check the dowel locations in the heads and in the block.
Usually the aftermarket heads or the dowels in the block will need massaging with a file.
Heads must sit flat on the deck before the bolts go in.
 

74Scooter

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Do not force it into place. This is common. Use a head gasket to check the dowel locations in the heads and in the block.
Usually the aftermarket heads or the dowels in the block will need massaging with a file.
Heads must sit flat on the deck before the bolts go in.

Used a brand new felpro gasket to protect the head surface.. it dropped right onto the deck without issue. I'm going to mic the holes and pins after lunch.

Thx!
 

74Scooter

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OK.. so I had to file a bit on the inner side of the dowel pins. Passenger side took more massaging than the driver but both settle flush to the deck now. Mock up with passenger side only looks good.

Gettin ready to apply AARP head bolts.... any pearls of wisdom?

Is torque spec. and sequence the same with aluminum heads? I'm looking at 95ftlb with AARP hi torque thread lube.. 3 step to final... inside to out.

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DNasty777

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Guess I deserve that for double tapping the "A"... tough crowd. :icon_fU:
LOL, but the way I do them is exactly like you describe, 3 step sequence with whatever final ARP asks for. Just make sure you lube the threads, under the bolt heads and both sides of the washer.
 

74Scooter

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LOL, but the way I do them is exactly like you describe, 3 step sequence with whatever final ARP asks for. Just make sure you lube the threads, under the bolt heads and both sides of the washer.

ARP does not give a torque spec. so I'm guessing they defer to the manual. Never had aluminum heads on any of my classics... always rebuilt the cast parts in the past. Unless I hear otherwise I'm going with 95ftlbs. And yup... lube threads and both sides of washers. Galling up these new heads would be a shame.
 

rumblefish360

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ARP does indeed give a Torrance spec. *I THINK* it’s 100’ pounds. Check there web site and use the part number on the box as a reference to get what your looking for.
 

74Scooter

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Ottmundr

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Which promaxx heads are these? I'm looking at ordering up a bare set of the CNC Shocker 185's with the 63cc chamber size. After tax, over two grand, kicking myself for not ordering them up last year.
 

74Scooter

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Which promaxx heads are these? I'm looking at ordering up a bare set of the CNC Shocker 185's with the 63cc chamber size. After tax, over two grand, kicking myself for not ordering them up last year.

These are the 171's/63cc, fully assembled.

I ordered them 04/2021, $1400 and change shipped.
 

74Scooter

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Head bolts in and torqued to 100ft lbs spec., is it just me or is final torque harder than it used to be? :lol:

Torqued heads with intake on and a few intake bolts finger tight to assure no alignment issues later. Air gap seems to fit better than the Weiand Action+ at the distributor. I had to clearance the gap to the dizzy base on the Weiand, plenty of room now.

Quick Q as I get the rockers back on. Keep the tabs from the head gaskets or lop them off? I seem to recall removing them with a cold chisel on my Ford build. Think their purpose was to hold the intake gaskets in place but the RTV on the water jacket ports should take care of that. Not planning on using the cork seals on the china rails... good bead of Right Stuff instead.

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TT5.9mag

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I cut em off so I can get a continuous bead along the gap. And I also use right stuff. That stuff is the shiz.
 

74Scooter

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^^^ Thanks.. that's what I'm thinking *** well.

One of these days... shop manual... lol.

Can I get a confirmation on a few torque specs:

Rocker shaft bolts 17ft lbs.

Intake manifold bolts 35ft lbs.
 

rumblefish360

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I just bend them down after there used to help position the intake to head gaskets. RTV is then used under and around both sides of the tab. Never an issue!
 
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