Thinking of going through with building the 455 F block. Which letter exhaust manifolds could I use for it so it goes into the ‘75 Salon? Thanks in advance for everyone that replies. ER

 

Depends on whether you're keeping the single exhaust with catalytic converter. If you're not, and you're going true dual exhaust, W & Z will work perfectly as that's what 73-74 455 Cutlass had. Otherwise you're kinda stuck with 75-76 455 manifolds, which have the crossover and the correct exit angle for the cat.

If you're going duals you also need to find a 73-74 GM A-body double hump transmission crossmember. Makes the job much easier and neater.

 

Thanks for the reply RR. No cats, and I have been thinking about the dual exhaust crossover. I have only come across one in since I have owned the car for around the last 12 years. Kinda of scarce. I am currently parting out a ‘75 and removed the single crossover. My neighbor, who is a welder by trade, said he cold combine two single and fabricate a dual. Have you ever heard of anyone doing this? ER

 

THIS ^^. I did the same thing for a 78 442 that I had.

 

You need to learn how to use the forum. You wanted a reply by e-mail but you have chosen to not receive e-mail in your preferences.
I did weld two crossmembers together to make a double hump. That was over 25 years ago and do not remember how I did it. A professional welder will know how.