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

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?

Thanks for reading.  

i did that a long time ago.......  66 gto with a big block chevy...

i had put headers on it when it had the pontiac motor and found that the frame cross member had collapsed..  the frame rails were too close together... the car had a lot of hard miles on it when i got it...   a few minutes at a frame shop showed me how to do it... i can post instructions on how to spread the frame properly... with the motor in or out... but i lack the dimensions between the upper control arm brackets... i have forgotten after all these years... i cannot remember everything...

i put a 30 over 402 in mine...  big block chevelle frame brackets.. solid motor mounts,  2-1/8" primary cyclone monte carlo headers...    scatter shield...  wide ratio muncie..  4:11 12 bolt posi...  L60-15 caldwell recaps..

do to my being lazy... and changing jobs... i never did get a cross member installed...   the muncie rode out there for almost 2 years... unsupported...  no problem...    i even made a shifter out of 3 pieces of aluminum bar stock... it was great...  

i had a tiny solid lifter cam in it...     290 duration... .575 lift... and yes i had to cut the tops of the pistons... got offset retainers and keeper for the used top fuel valve springs i had on it..

it was a blast...  i sold the car in 85 and still have dreams about driving it...  it did take 5 years to regain my hearing..

oh.. one more thing... i always left the strap above the glove box only bolted on one end...  anybody who grabbed it.. had it come out in their hands...

my sister took a jumbo jet on vacation for the first time flying.. she said she was nervous.. until the plane turned onto the runway and released the brakes..... it pushed her back harder and harder into the seats...  and she said she calmed down... and felt comfortable.. then she realized ... it was just like driving in my GTO...


with the big block...  you do want to use a load dropping relay for the starter...   just to make is start every time...  

I had a friend that put a rat in a 69 Judge and did 12 second quarter miles.

BUT if I were having the issues you are having with the 1966, I'd call Advanced Adapters and ask if they have a knowledge base (which they probably do) and see if "slip-fit" headers might be right for you.

I know slip fits are made for the small block and help in the S-10 v8 conversion, which is what I was interested in at the time. You can goggle Advanced Adapters and talk with they're engineering staff, they are good people with great knowledge and they take pride in what they do.

Don't give up, never say never.

I have a 700R4 with a four wheel out; if anybody is interested.

I'm located in the Central Florida area.