[RatPin]

I have an '85 350 block with some new GM vortec heads I'm putting in my project truck. I bought some stailess headers from summit but find they seem to hug the block a little too tight. The drivers side hits the casting notch in the block just above the oil pan gasket. I took my grinder and removed some material from both surfaces to give me about less than 1/8" clearance but am still worried it might rattle and hit the block when the engine is running.

Do vortec heads have a different angle on the exhaust port side that would reduce the header clearance? Will anything be affected by me grinding that casting lump down on the block or is that just a big chunk of unecessary steel?

These are the headers I am working with...
Summit block huggers

[68NovaSS]

There's no water jacket issue with the casting lump, just don't go into the pan rail. Once the headers are bolted solidly in place, you're not going to get much movement, if you could get 1/4 inch you should be OK.

[RatPin]

I just find it odd that I cannot find any other mention of this problem as popular as the summit headers are.

[RatPin]

I wonder if summit sent me the wrong block huggers. I guess I will have to eat the return shipping charge...

[lmsport]

The Vortec exhaust flange location is not interchangeable with the pre-93 GenI exhaust flange location. Very close, but different.

[RatPin]

That is the first I have heard of that. Everyone says they are all the same, but that would make sense. So which style header would I need to be looking for?

[RatPin]

Can anyone confirm or deny this? I have called header manufacturers like Sanderson and even they say there is no difference in the flange is the same. I need to order huggers, but don't want to have clearance problems again.

[eric32]

I don't know if this will help you out but I do believe it will some. When I got my 96 s10 it had a 350 vortec in it with the s10 shorty swap headers and I eventually sold that engine cause it was worn and tired and I wanted older style cylinder head build and the headers bolted right up with no issues. From what I can gather the exhaust bolt pattern is the same with no difference between the pre 86 style cast iron heads and the 96-00 vortec heads. I had no issues with bolting my headers up.

[RatPin]

Interesting. I dont think going from vortec to standard would present the same problem, but if you were going from standard to vortec, then I would be a little more interested in your results.

When I put the summit huggers up to my heads, the collecter hit the block long before the flange could seat on the heads.

I guess I'll just order the hookers and cross my fingers that I recieved a bad set from summit.

I'm really surprised nobody has a solid answer on this one.

[RatPin]

Hard to beleive I have already stumped the "knowledge base"

Here's a blurb I found that just lends more confusion to it all.
http://www.nastyz28.com/forum/showthread.php?t=219391

I'm thinking of trying speedways Tru-ram manifolds. They appear to be well out of the way of the plugs as well as giving me ample clearance from the block. They are expensive though...

[RatPin]

For anyone running vortec heads and considering speedway's tru-ram manifolds, I would not recommend it.





Back to the drawing board. I've order some hooker huggers now. Wish me luck

[RatPin]

The gains of using vortec heads are nice, but they do present their share of problems in custom applications alright.

[cobalt327]

There is no difference in the angle of the exhaust port flange of a Vortec c/n 062 and a 882 cylinder head, nor is there any difference in the bolt hole location as measured from the deck to the bolt holes.

If you have a clerarance problem I'd suggest using a thick gasket like the Spectre Performance p/n 416 or similar 1/8" thick gasket. Double if necessary.

[RatPin]

Good news! The hookers fit great. Got the downpies fabbed up now need some flex pipes.

[RatPin]

Hookers