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Old 11-29-2019, 08:49 PM
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footjoy footjoy is offline
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Default Timing cover new vs old

I was talking to my machinist and I mentioned I was putting on tri power and had to go back to older timing cover with bumpout for thermostat cover.

He said he thought the newer ones had a different design and ran cooler.

Does anyone have any info on that.

Thanks

Greg

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Old 11-29-2019, 09:07 PM
tom s tom s is offline
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There are 11 bolts out there with the dimple for a tripower.I run a 4 bolt,a 8 bolt and a 11 bolt on my current cars and I see no diff in any of them.If I have a choice I would find a 11 bolt with the dimple.Tom

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Old 11-29-2019, 09:13 PM
tom s tom s is offline
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here ya go!
https://www.ebay.com/itm/Pontiac-400...QAAOSwnk1dryhw

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Old 11-29-2019, 09:18 PM
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I’ve seen covers with the dimple to clear the Tri-Power thermostat housing made by the factory as late as 1974.

The later covers will need a little work on the backside of the upper bolt boss to provide clearance for the thermostat housing, just a file the boss down by about an eighth of an inch and you’re good.

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Old 12-04-2019, 03:59 AM
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The three coolest running cars in our club have the 8-bolt water pumps. On paper the 11-bolt sure looks to have the advantage, but we haven't seen that to be true. This is after tightening up the plates in both styles.

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Old 12-08-2019, 11:30 AM
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Another option is finding an aluminum thermostat housing and weld/building it up on the inside so you can grind the clearance on the outside of the thermostat housing.

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