Being new posted this question In the wrong forum.
Got a most likely 73 cutlass 455 and. A 400 turbo, car drives and runs like a dream but performes like a small block. this is an factory ac car . I was hoping to put some headers in it but is worried about the fit. I also wanted to put a 800 cfm edelbock and intake manifold, currently has a 600 cfm edelbrock. Wanted to upgrade from stock hei? To billet package w10mm wire and hp pluggs. Any thoughts and recommendations ? How much power can I except? Up from 250 hp stock?

 

I doubt you'll find any off-the-shelf headers that fit without mods. Keep in mind that you have rear-steer. The commonly available headers fit front-steer cars.

 

Rear steer? I am not familiar with that can you please explain. But from reading here sounded like the engine had to come out and up a little bit to wiggle it them in? Wich in that case in think I keep the original manifolds and exhaust 2.1/4 pipes from there and maybe flow master. 50's

 

Was any engine work done to the 455 before put in the '61? It being a '73 engine, you have the low compression engine.
Rear steer means the steer gear box is behind the front wheels, as "A" body cars the gear box is in front of the wheels.
The right side should work ok. The drivers side will need a couple of tubes moved.
The distributer upgrade will be good. A good 750 Holley or a E-brock carb will be an upgrade also.
What letter is on the cyl heads?
Gene

 

Cfd411 83 on the heads (Fa) block I don't know about engine work since this probably was done ten years ago or more. My forensics tell me that is was an older guy that cared about the car greatly and did not drive it much (99%) of everything works. And looks great. I think I am going to skip the headers then . Do you think there could be an issue with clearance under the hood w edelbrock intake?

 

If you'd like to save a little money and fuel in this economy, consider using a Q-Jet that'll equal or surpass your other choices.
There are many rebuilders out there that'll set up a Q-jet to your engine and intentions with your vehicle, and it should be right the first time.

 

Lay a straight bar across the top of the fenders and measure from the bottom of the bar to the carb. that should give you an idea of how much room you have.
Is your car a bubble top?
We also need some pic's of the car and engine.
I would guess you have big block Olds manifolds on the engine. Also a nice dual exhaust sys with 2.5 pipes should help also.
A Q-jet would make a great upgrade, that 600 is ok, but a nice Q-jet carb would help.
Looks like maybe you have "C" heads. At number one spark plug and number 8 spark plug, what letter is there?
Is your A/C hook up and working?

Gene

 

These are J heads and yes ac is working, clearance is about 1-2"

 

Sorry it's a convertible

 

Yes, you have the '73 to '76 low compression engine. You can swap heads to improve. "C", "E", "G" or "Ga" heads. The "G & "Ga" heads have factory induction harden valve seats. You could mill .040 off your heads and that will improve. If you remove your heads and find you do not have the factory steel shim head gasket, I would mill only .020 off. Before you they may have milled the heads, so you need to have them "CC"d to find out your combustion chamber size. I presume you have the cast iron intake. An E-brock "O4B" intake is a very nice street manifold, otherwise use the E-brock performer.
We still would like to see some pic's

Gene

 

Yes cast intake and and exhaust manifolds. It sounds like a major overhaul would be in place at a later date, perhaps when something else needs attention. Car runs excellent so i am now down to distributor and carb + exhaust. my intentions are just to make the car the best it can be without going crazy on $$$ and it really is an unbelievable cruise car! the thing is that I also have 55 chevy 454, that motor would hardly scare a puppy when I bought it. i did some performance upgrades to it and (headers, exhaust and tune) the car is an absolute wild beast now!