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1985 Corvette motor question (heads)

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Old 07-11-2018, 06:41 PM
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JTSK
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Default 1985 Corvette motor question (heads)

On my 85 I had developed an intake leak, so I took it apart and found that the motor isn't original to 85, it's a roller block with roller lifters, but with the stock 85 heads. After taking a closer look I had 3 valves that were about to lose their keepers, and so I yanked the heads and took them to a machine shop. I get a call that the heads are basically shot and not worth the money to being back in shape, so..... I began looking for heads, Summit, Jegs, etc. I'm not building a race motor, just want a good dependable daily driver. I began noticing that all the heads state will not work with factory roller cam or either will not work with TPI. Has anyone had an issue like this? What are some recommendations? I'm wondering why they wouldn't be compatible with TPI? Is it because they don't have an EGR passage?? Any help is appreciated. I am perfectly OK with cast iron heads too.
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Old 07-11-2018, 07:21 PM
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84 4+3
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Some tpi intakes have a different bolt angle toward the middle. Straighter down if you will. That is the difference.

624 heads are pretty junky. The summit iron heads, 165cc runner, are decent. They are dart heads, have egr and would be a nice mild upgrade permitting intake pattern. (I don't remember if vettes were different or thirdgens.) That's my suggestion.

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Old 07-11-2018, 09:18 PM
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C409
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..... Look for a set of the '86-up vette aluminum heads … they can be had for as little as $300 pair … but at $600 they'd be a better deal than ANY iron heads …..
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Old 07-11-2018, 10:07 PM
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Get a pair of 88 and up 113 heads. You can find them reasonably priced and will bolt right on and be better than those Summit iron heads
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Old 07-11-2018, 10:32 PM
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My car came with a lot of paper work , i have the engine build sheet (355 cu in.) and in mine in the cyl heads line it states: Dart Iron Eage (200 in. Runners, straight plug)...
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Old 07-11-2018, 11:50 PM
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Originally Posted by IBVETN2 View Post
Get a pair of 88 and up 113 heads. You can find them reasonably priced and will bolt right on and be better than those Summit iron heads
I'd be worried about comp ratio depending on the piston. If they're flats it'll be roughly 11:1... all I did was make a suggestion that would be as set it and forget it as can be.
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Old 07-12-2018, 03:00 AM
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Originally Posted by IBVETN2 View Post
Get a pair of 88 and up 113 heads. You can find them reasonably priced and will bolt right on and be better than those Summit iron heads
If I'm not mistaken, I believe the 113 heads have 58cc chambers, while his original 624 heads have 76cc chambers. In addition, I think the 113 heads have raised intake runners, which may not be compatible with his intake manifold, and of course, center bolt valve covers.
For an economical upgrade, the iron 993 heads would have the same CR, better flowing ports than the 624 heads, compatible port locations, and use the same valve covers.

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Old 07-12-2018, 07:08 AM
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when you guys say 113, 624, and 993 what exactly does that mean? I still don't understand why some heads won't work with a roller block.
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Old 07-12-2018, 08:32 AM
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Originally Posted by JTSK View Post
when you guys say 113, 624, and 993 what exactly does that mean? I still don't understand why some heads won't work with a roller block.
That's the last three digits of the head casting number/part number. If you type in GM 624 heads you'll see your heads 113 for the newer ones etc.
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Old 07-12-2018, 01:59 PM
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Hot Rod Roy
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Here's a good video on iron SBC heads:
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Old 07-14-2018, 07:34 AM
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Thanks for the help guys.
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