Mopar Action On-line – Tech Questions
Glenn Menard, Memphis, TN, 1973 Plymouth ‘Cuda 440
I am planning on replacing the exhaust system on my ‘Cudaand wanted to get your opinion on a few options. The car has a fairly”warmed over” 440:
0.040 over – Kieth Black pistons (set up as floaters) – true C.R of10.89:1 – Top of block chamfered to unshroud valves – Stage V heads, portedusing Mopar’s porting templates, chambers cc’d and polished, 11/32″ stemvalves (bronze guides), titanium retainers, Crane 1.6 rockers – Hughes solidcam 0.050″ duration ~ 238 intake, 244 exhaust; lift ~ 0.569 intake, 0.579exhaust (I don’t have the exact specs here at work, but it’s the earlierversion of their max velocity series) with matching springs – Assembly isbalanced – Mopar M-1 single plane intake – Holley 850 carb (list 9381 if Iremember correctly – came with no choke). I used to ride submarines so I hada lot of time to plan this one!
It cruises at ~ 3400 RPM on the highway. The car does not see any tracktime, but I must admit I do get on it once in awhile. The shift light is setat 5800 and by the time this old fart reacts, I’m hitting 6100 – 6200 rpm’swhen the 727 shifts. (It seems every Mustang owner thinks he has the fastestcar in the world and of course it is our duty as Mopar owners to show themotherwise!)
I am currently running Hooker Supercomp headers with 1 3/4″ primaries and 21/2″ pipes (w/crossover) and flowmaster mufflers. I am planning oninstalling a TTI system, but am not sure of the best way to go. Options are:
1. Keep the Hookers and run either a 2 1/2″ or 3″ system (TTI’s web siteshows they offer adapters for the Hookers).
2. Change to TTI headers (1 7/8″ or 2″ primaries) and run either 2 1/2″ or3″ system.
I have heard for years that the 440 responds best to 1 7/8″ primaries, buthave also heard good things about the 2″ headers. Is a 3″ exhaust system toobig for the street (sacrificing flow velocity for upper rpm capability thatthe car never sees)? I know you guys have done some extensive testing withdifferent exhaust configurations and would value your opinion.
The TTIs are awesome headers in any size. For your application, it’s kind ofa toss-up whether to use the 1-7/8″ or 2″ primaries.
HP-wise, the Hookers really aren’t bad, either, the biggest advantage thatthe TTIs have is fit, freedom from rattles, etc.
For anything over 450-475 HP, the 3″ pipes are the way to go. Again, basedon your specs, it’s borderline. When pressed, however, since there’s littledoubt that you like to crush a little rice now and then, I’d say go for themax: 2″ primaries, 3-1/2″ collectors, and 3″ pipe all the way back.