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Discussion Starter · #1 ·
I own an 96 DGGM Impala with 270,000 miles on it and want to replace the heads, both #5 bolts on the heads have broken bolts inside the bolt holes in the heads and I don't have the confindence to tap then out and shops near me won't touch the car. So I see this as a good excuse to get a set of new heads. I wanted to stay with something close to stock so I went to the GM perfomance parts site I saw only the LT4 aluminum heads available, I called a local dealer and the sales guy also comfirmed this was the only one available. (Part#12363287 LT4 Design Aluminum Cylinder Head)
Question: since these are the aluminum heads and the port sizes are differnt will I need a different intake?
Mods so far have been cool-air intake,Hooker headers, PCM reprogrammed, throttle body bypass,Borla exhaust,Eibach springs and Bilstein shocks.
 
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Discussion Starter · #2 ·
#5 bolt? of the head bolts or the exhaust manifold bolts?

What other mods have you done to your car?

A much more cost effective thing to do would be ot pick up a set of ported stock iron or aluminum heads. But I would not do that unless you change the cam out also. But with 270k miles, I wouldn't do either without checking the bearings in the bottom end also.
 
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Discussion Starter · #3 ·
I've heard of some people using a stainless welding rod to get broken bolts out of iron heads. Something about the welding rod will stick to the bold but not to the cast iron.
I read this either on this form or the other one, don't remember.
Josh
 
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Discussion Starter · #4 ·
The LT4 stuff is nowhere near as great as newbies think. Not that it is bad either just that there are a lot of other options many of them easily arguably better for a stock shortblock.
Besides the LT4 intake is no longer available so you will get gouged several times the new price for a used one on e-bay.
 
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Discussion Starter · #5 ·
Don't waste your money on the LT4's. There are a number of better choices. At 270K you might as well spring for the complete rebuild.
 
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Discussion Starter · #6 ·
Make sure if you choose to reuse your existing heads, check to see if they are cracked. They tend to crack between the center bolt and the water jacket.
 
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Discussion Starter · #7 ·
Batwomen,

I have a set of stock LT1 iron and a set of aluminum 643s
for sale. Sent you a PM on details.

Dave.
 
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Discussion Starter · #8 ·
Hey Thanks for all the quick responses!

One mod I forgot to list was the gears, I went from the stock 3:08 to 3:73's - I am SO glad I did it!
Also, AydiSS asked about which bolts, the bolts holes on the heads for the headers/exhaust manifold. When I went to put the headers on a few years ago I found on the passenger side the #5 bolt was broken off inside the bolt hole. I wondered why I could get the bolt started,duh!Later on after several runs at the track :eek: the driver side #5 broke off. I went to several local shops to see if they would tap out the bolts, I got two answers one "No" and the other was remove the headers and have the car towed here and then we will do it for maybe about $400!That header install took my boyfriend and me 12 hours!
I'd love to get a new engine but my funds are limited. I still want to drive the car and have some fun but with the amount of miles on it I can't see buying AFR's or Trickflows, I was quoted $970 for the stock heads. Besides gaskets and checking out the bearings. I was trying to figure out what other parts I needed, one guy says stick with the stock cast iron LT1 heads, which means I won't need a different intake.
Any other suggestions?
 
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Discussion Starter · #9 ·
With stock iron or aluminum LT1 heads you won't need a different intake...I'd say call around to local salvage yards and price them out...then also call around to a few machine shops and ask them if they can get a broken exhaust bolt out of a cylinder head if you bring them the head (same amount of work as new heads, but much less money, just gaskets and the machine shops time).

A good machine shop won't charge much at all...it's MUCH easier to do when the head isn't in the engine bay.
 
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Discussion Starter · #10 ·
See if you can find a local Gearhead with a welder. I would disconnect the PCM first. Your other option is try try to drill it yourself. Sometimes they aren't in very tight and will come out with just a reverse twist drill. In my case I used a stick welder after I broke an extractor. Do a search for broken exhaust manifold bolt.
 
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Discussion Starter · #11 ·
I would just leave it alone-if there are no leaks, why bother? If there are leaks, you may try changing gaskets and using ARP bolts-those won't break. I run Try-Ys with one broken bolt and I have no leakage.
 
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Discussion Starter · #12 ·
Unless your going stroker, ported LT1 castings will be great. LT4 stuff is over rated. Oh yea, you would have to rework your intake significantly(add material, then port it) to make it work on LT4 heads. If you really want new heads, geting AL LT1 heads, and having them ported by AI or LE would result in better gains than just buying LT4 heads, since LT4 runners have so much space. If you look at the FAST ET page, alot of people are going very fast with port AL LT1 castings. A Llyod Elliot package is prolly a way better bet than LT4 heads from GM.
 
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