does anyone know how to tell the difference between big block and small block Herman headers ? I have a set that are supposed to fit a 455 but I see no numbers on them only the Hedman tag on them. Thanks

 

I would say at least grab a tape measure. Should be very easy to identify. Post pictures and those in the know here will answer immediately.

 

will do and thanks .i tried to edit my title for the incorrect spelling of hedman but wasn't able to

 

 

Fixed your title. Can't help on the headers just looking at your picture.

 

Thank you Eric

 

Interesting how they spell “hedders” on the stamp. The guy I got these off said they were on a 70 442 with a 455 . I bought them just to use on my run stand but they’re actually in pretty good shape ,maybe use them on a future project .

 

I bet there is a part number stamped somewhere. You might call Hedman and ask if they could help identify them.

 

Check around the collector flange, some companies used to stamp part numbers there.
Did you use these on your run stand? SBO hedders on a big Olds wont clear the starter or oil filter mount correctly

 

I did finally get back to these hedders after some wire brushing at the flange I found a part number 58150. They are big block olds hedders I’m using them on a 350 I’m working on the run stand . They did need to be clearanced around the motor mounts but for 50 bucks I don’t mind banging them in a little.