Anyone ever use a header adapter plate to convert a standard 23* chevy header flange to a Stahl bolt pattern for 1 7/8" tubes or bigger? What brand did you use? Do you need two gaskets for this setup (one between the plate and the head, and between the header and the plate)? Finally, do you port the plate to the exhaust port on the head or to the header flange?

 

Most use two gaskets but I have seen some use gasket maker and it work....
On my car I elected to redrill my AFR heads to the stahl pattern rather than running the adapters. Yes you will want to match the adapters to the exhuast port.

 

I've had a couple rounds of problems with leaks, but I'm trying RTV this time.

I'm not sure what the brand of adaptor plate is. Kind of messy...

http://memimage.cardomain.net/member...6_151_full.jpg

Ryan

 

If you are using Stahl headers I suggest getting the plate from them. Hooker may also use the Stahl pattern, Hedman uses a different pattern. The plate is generally ported to match the cylinder head and can use a gasket in between. I have had great luck with the MrGasket 5904 and 5908 gaskets.

 

I am either having a custom header made, or at the very least using the Hedman 1 7/8" LT1 header. I thought those used the Stahl pattern, could be wrong.

How much/hard is it to redrill the heads?

Also, can the plates be port matched without taking the heads out of the car? The engine is assembled and installed in the car. Cardboard stencil? (obviously if I redrilled the heads they'd be removed, lol)

 

Take some grease and smear it around the ports. Line up the adaptor and then etch in the port outline that the grease left you.

I'm using the hedmann headers. I thought that the Stahl pattern was different, but the Reher Morrison ones work. There is a set in the Jegs catalogue that look correct. There are 3 individual pieces per side instead of a single plate. Easier to work with, IMO.

Ryan

 

My AFR heads already had the pads there, I got a print from Stahl. Made a template and drilled the pattern as they would be drill from AFR.

What heads do you have? If you hit water I was told to seal the bolt holds with silicone.

-Bobby-

 

I have AFR 210's.

96speed, what brand plates do you have? I think the ones you're talking about are the Dynatech ones? So you're saying that the Reher-Morrison ones are the correct pattern for the Hedmans?

 

If you purchase adapter plate headers from Hedman they come with the plates and hardware. You could shoot some paint over the exhaust ports and while its still wet bolt the plate on to transfer the port shape over. Better yet just port the plate to match an LT1 exhaust gasket. The mismatch won't hurt a bit and could inhibit reverse flow.

 

I guess I'm a little confused, lol. Wouldn't porting them to an LT1 gasket make it smaller than the exhaust port in the head? My exhaust ports are pretty big.

 

Birdie: I'm not sure who made my plates. Regarding the above question, I think what Mark is saying is to open up the adaptor plate to whatever gasket you are going to use.

Ryan