Need a pair of mopar "J" smallblock heads

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rewguy
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Need a pair of mopar "J" smallblock heads

Post by rewguy » Sat Nov 04, 2017 7:19 pm

I realize theyre pretty inexpensive. Ive found three pair for under 150$ ea pair. But I figured if i bought them from someone on here, I'd be more likely to get a set that wasnt cracked, etc. lol
Thanks.

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Re: Need a pair of mopar "J" smallblock heads

Post by ProPower engines » Sat Nov 04, 2017 7:55 pm

Where are you located??
Real Race Cars Don't Have Doors

PackardV8
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Re: Need a pair of mopar "J" smallblock heads

Post by PackardV8 » Sat Nov 04, 2017 8:05 pm

I'd be more likely to get a set that wasnt cracked, etc. lol

Most we see are cracked, but I'll mag those which haven't been scrapped.
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Re: Need a pair of mopar "J" smallblock heads

Post by Diodedog » Sun Nov 05, 2017 12:05 am

Probably close to 50 percent of the dozens I've done have cracks in the exhaust seats. Most of the time the cracks are very mild and never leak. If it's a stock rebuild or mild street and strip engine, they're usually fine. The big block 452 heads have the same problem, I believe the seats were cracked from the hardening process before they even left the factory.

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Re: Need a pair of mopar "J" smallblock heads

Post by mag2555 » Sun Nov 05, 2017 6:37 am

I have seen many a cracked 452 casting also , and yes they looked like from the factory!
I would still put seats in to get it all right unless you don't mind hydrolocking the motor some day and this always seems to happen above 5000 rpm and not at idle, and in doing such can take out a cylinder wall.

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Re: Need a pair of mopar "J" smallblock heads

Post by PackardV8 » Sun Nov 05, 2017 1:33 pm

Might as well ask, what is the application? By the time the OEM J-heads are put through cleaning and magging enough heads to find two good ones, milled, hard seats, 2.020" intakes, new guides, valves and springs, pay shipping, they're pushing the cost of aftermarket aluminum heads.

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Re: Need a pair of mopar "J" smallblock heads

Post by PackardV8 » Sun Nov 05, 2017 2:57 pm

We checked and we've got a pair with no cracks - $200 for the cores, or will build to suit.
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rewguy
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Re: Need a pair of mopar "J" smallblock heads

Post by rewguy » Mon Nov 06, 2017 1:24 am

The customer is determined to maintain a completely stock appearing cylinder head. They will be cut for 2.02 valves and have light bowl work done. They will end up on a 408 that should be around 415-425 hp. Hyd roller, 9.5-1 deal.

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Re: Need a pair of mopar "J" smallblock heads

Post by rewguy » Mon Nov 06, 2017 1:26 am

PackardV8 wrote:
Sun Nov 05, 2017 2:57 pm
We checked and we've got a pair with no cracks - $200 for the cores, or will build to suit.
Well...... Can you get me a price on labor upfront so I can decide if it's in his budget? I will have valves here...... But.... Tell me what you think they need. Will be run on 92 oct pump fuel.

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