I have an exhaust leak on my '79 400 4spd Trans Am. I took it to the shop
and one of the studs on the exhaust manifold is broken so my mechanic said
he would have to remove the exhaust manifold and drill it out. But he
thinks the exhaust manifold bolts will break and then he would have to
remove the head. The bolt on the exhaust looks fairly bad. Am I better off
risking him trying to remove the manifold or should I just jump in and have
the block removed and freshened up. The latter is $2300 and the former, who
knows? Are the manifold bolts fairly weak? Any advice will be appreciated.
You may want to try a good exhaust shop. I had a couple of broken studs on
my 69 GTO and I watched the guy blow them out with an acetylene torch, no
kidding. They deal with this stuff all the time and know how to remove
stubborn bolts and studs. As far as the manifold bolts, I've removed a lot
of them over the years and have yet to break one. It's more of a worry that
the head will get rounded off IMHO on a Pontiac engine.
$2300 sounds like a standard bottom end freshen price to me. Before you jump
into that, think about what you want to do with the car before you decide.
At a minimum you will want to replace the rod bolts with ARPs and have the
rods shot peened and resized. This is the weak area of the ponchos but it's
cheap insurance. If I had the engine apart, I'd at least have the heads
pocket ported and upgrade the cam to something suitable to the compression
(you're probably around 8.2:1) like a 214/224 but make sure the shop
guarantees that the valve spring clearance is adequate for the gross valve
bolts. If they break off, convince aforementioned skilled TIG welder to
shrink the broken studs with the TIG torch, then build up a dome on the
broken end and weld on a nut. A little trans fluid and it will come
right out with a socket. A gentleman by the name of Ouzts that teaches
up here in Laramie at Wyoming Tech has that trick down to a science.
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