1966 GTO WITH A CHEVY 454 ENGINE SWAP: THE RIGHT HEADERS??

This is not about me not wanting a Pontiac engine. If You have one to donate I will gladly accept it. It's a project and this nice engine is only temporary. I go to school full time (halfway done) therefore I live on a budget but dedicate much of my time to my '66 GTO and '70 Chevelle.

I am done with the suspension and chassis work on my 1966 GTO. Since I couldn't come across a nice and affordable Pontiac engine I built a 454 BB (open chamber small port oval port heads) with a comp cams 270h and 858 magnum lifters, and the rest of the other goodies.

Installed engine swap motor mounts for intermediate GMs from TransDapt. Engine fit well along with a B&M TH400. HOWEVER, the headers I had for them (Patriot "Clippster" Style Headers, Part # H8012-1) are close to fitting but not quite.

I bought the Headers at a hot rod swapmeet (new), I called the guy back and he told me they should have fit although... when I cross referenced the part # at JEGS:

H8012-1 - Patriot ''Clippster'' Style Headers Details
GM
Fits:
1967-81 Camaro
1968-77 Chevelle/Malibu/El Camino
1970-77 Monte Carlo
1968-79 Nova
1965-74 Passenger Car/Wagon/Nomad
Notes:
Shorter design for maximum ground clearance on cars lowered up to 4''.
Not recommended for generation six 502cid engines with aluminum heads.
Fits manual and auto trans floor shifts only.
Big block frame stands and motor mounts must be used to insure proper engine location and header fit.


The guy is going to help me get the right ones, I'm thinking 1966 Chevelle Headers, I just don't know which will be the better choice.

Have any of you put a Chevy BB into a '66 Pontiac GTO/LeMans? If so which headers worked for you?

Which Headers worked for S&K Performance in the '70's when they swapped a 454 BB into a '67, and where can I find them? There's a book out there, the Chevy Bible, published in 1974 that touches up on it, however I can't find it.

Thanks for reading.  

Where is there a good place to purchase a turn key Pontiac engine?  

I think you are on the right track with the 66 Chevelle headers, of course only trial and error will tell for sure since you are using aftermarket motor mounts which might slightly change the position of the motor. As for turnkey Pontiacs, check the ads in HPP, there are several builders selling crate engines.
Steve  
Trying to help... 'cause we don't all have to learn the hard way!

66 Chevelle headers will work Hooker or Hedman for sure-Aftermarket exhaust products from folks who have extensive R&D depts.may cost slightly more but install easier and last longer-thicker flanges and bolt holes tend to line up more often than not.Of course these are not the only reputable manuf.