[callmejavier]

Would the heads from a 1987 Chevy 350 Targetmaster Crate Engine have hardened valve seats? The casting number is 3998993. I assumed they would have hardened seats suitable for running unleaded fuel due to the year. The machine shop says they don't, and should have hardened inserts installed while I'm getting the valve job.

I'll be using the engine in a daily driver '80 malibu wagon. I'll be towing 5,000 pounds 600 miles per year with mostly city driving the rest of the time.

Based on this application, I should use hardened seats, right?

Thanks for any info.

J

[enginejr]

Every factory head after the lead cutoff has hardened seats. The up-sell seats they want to sell you ARE harder, but not by much.

[oldbogie]

Originally Posted by callmejavier

Would the heads from a 1987 Chevy 350 Targetmaster Crate Engine have hardened valve seats? The casting number is 3998993. I assumed they would have hardened seats suitable for running unleaded fuel due to the year. The machine shop says they don't, and should have hardened inserts installed while I'm getting the valve job.

I'll be using the engine in a daily driver '80 malibu wagon. I'll be towing 5,000 pounds 600 miles per year with mostly city driving the rest of the time.

Based on this application, I should use hardened seats, right?

Thanks for any info.

J

They should have induction hardened seats, but send us the casting numbers so we can check, I'm always leary of the Target Master engines as they tend to be built from whatever's laying around.

Bogie

[SSedan64]

They may not have hardened seats. Here's the dates they were used.

3998993 - 307/350 - 68-79, 1.71/1.50, 1.94/1.50, 76cc

[callmejavier]

Thanks for the replys.

Apparently they have been used long after 68-79. These heads have a large '87' cast into them along with the casting number. I would think that after this amount of time GM would be casting new heads based on the 68-79 form rather than using heads lying around from that time.

J

[SSedan64]

Originally Posted by callmejavier

Thanks for the replys.

Apparently they have been used long after 68-79. These heads have a large '87' cast into them along with the casting number. I would think that after this amount of time GM would be casting new heads based on the 68-79 form rather than using heads lying around from that time.

J

Are you sure thats the casting date? The casting mark usually has day-month-year (*10 11 7*) something like that on a little pad.

[callmejavier]

I'm not sure when they were cast, but there are '87's cast on both heads with no other numbers other then the casting number and a plate with '131' on it.

Is it true, after a valve job, the original induction hardened seats are no longer viable, and 'steel' seats should be installed to retain hard seats for use with unleaded fuel??

[oldbogie]

Originally Posted by callmejavier

I'm not sure when they were cast, but there are '87's cast on both heads with no other numbers other then the casting number and a plate with '131' on it.

Is it true, after a valve job, the original induction hardened seats are no longer viable, and 'steel' seats should be installed to retain hard seats for use with unleaded fuel??

Who are you taking these heads to, living in the same city you do, I probably want to avoid these people.

Anyway, it depends on how deep the seats need to be cut to restore them. Induction hardening is actually fairly thick, just ask the guy porting a set of these type heads. But since I haven't seen them, its hard to tell if this is necessary or not. If the seats aren't burnt and this is just a dressing to restore angle and concentricty and this is the first time they've been cut since manufacture, there should be plenty of hard material left to work with.

Seattle's a pretty big place I'd recommend shopping around for other opinions.

Bogie

[callmejavier]

Thanks Bogie-
I'll let you know about these guys after the work gets wrapped up.

j