I found these headers on ebay:
https://www.ebay.com/itm/OLDS-CUTLAS...-/182850971141

This is what I have on the car now on the passenger side:
http://i.ebayimg.com/images/i/142220...-1/s-l1000.jpg

The crossover input on mine (passenger side) is plugged with a 1 inch pipe section with a cap welded on.

Do you think this will improve my horsepower over what I have now?
How much better do you think it would be?
I currently have 2.5 inch straight dual exhaust out the back.

 

There was a thread on these exact headers a few weeks ago. Try the search function and you can probably find it.

 

No they will not bean improvement on what you have now. We have discussed these a few times.
https://classicoldsmobile.com/forums...manifolds.html

 

Thanks for that info.

I also managed to find a few more threads about them. I agree the airflow doesn't look to be too good after reading about them. Like others said, I would probably lose horsepower.

I seen long tube headers online for the 455 but I'm not sure if they will fit in an 87 Cadillac brougham with the olds 455 v8. It is a big engine bay, but I feel like it might be a tight fit.
I also see comments on some headers for the 455 that the oil filter might be in the way (I use the PF24 filter), and the starter might be in the way too (I have a full size High Torque starter I bought for the engine).
I used my 307's engine mounts when I did the swap, I don't know if that helps to determine clearance with the frame?

 

No, the mounts match the frame pad, makes no difference in height, Joe P taught me that. You could try the Hedman shorties or just get the BBO high Performance manifold's from Thornton. I believe A body headers will fit but why on a heavy Cadillac?

 

I have full length headers on my sbo on my 77 Pontiac which should be the same frame as your caddy. I'm using A body headers so I'm going to assume A body BBO headers will work. I have some BBO headers you can buy for cheap to see if they work. The are a headman part number. They need some TLC if you decided to use them.

I did need to clearance the firewall a bit and remove some of the braces that bolt on between the front crossmember and frame.

 

I seen these from Hedman at summit racing:
https://www.summitracing.com/parts/h...ake/oldsmobile
the 2.5 inch exit would match good. Are these like what you have? If they cleared your starter and oil filter I assume it should clear the frame. These engines all mount to the frame with the same height?

I like it because nobody expects a big land yacht to be faster. I'm interested to see what my 1/4 mile ETA will be this year.

 

If it were me, I would make a deal with copper on his BBO headers, clean em' up good blast some good high heat paint on them and they should last years.
The ones you posted will look the same as coppers after a few months anyway.
I would buy a set of Remflex graphite exhaust gaskets for the install as well. A mini starter would make things much easier if it needs replacement in the future . JMO

Eric

 

Does a mini starter have descent torque output and reliability like the full size starter? It should last a long time?
coppers are the same part numbers as the ones in the link?

 

Im using a summit brand mini starter. Works awesome. Yes my headers are that same part number. I fixed a few issues with them from when i got them but never used them. They just need to be blasted and painted.

 

I use a Powermaster mini starter. Have had it on for about 4 years now, no issues ,nice and light.
The Summit brand would probably be just as good since copper mentioned it " works awesome"
I have other Summit specific parts that I have no issues with to date =, so if its a little cheaper, heck Summit is the way to go.
I'm sure you will be happy with his headers !