Joined: Thu Dec 14 2006, 04:59AM
Location: Italy
Posts: 147
Hi everybody! I'm upgrading exhaust system on my '66 300, 2,5" TTI with Dynomax mufflers. Casting numbers on manifolds are: 2532464 on passenger side, 2463107-4 on driver side. On TTI exhaust chart these manifolds seems to be 3" in diameter. What I have to choose? 2,5" or 3"? I have a stock 383, I will upgrade carb and intake, but I don't know if I will change camshaft.
SportFury440 wrote ... If you don't plan on doin much to the 383, the 2.5" will work better... !thumb
I agree. Your bottleneck will be the cam so you won't be breathing in all that much.
Off topic, but, I have read more than once that unless you're gulping humongous amounts of intake, 3" pipes are overkill on most engines and even detrimental sometimes. (I'll put on my flak jacket now )
Nope you are right Stan. Unless it is the mother of all rip snorting 383's stick to 2.5". My Fury has a full 3" system coming off of TTI headers. I have had several engine gurus tell me I am giving up a lot in the low end because the back pressure is to low. I tend to believe them. My 440 isn't a super hot engine, but mildly worked over. It doesn't seem to have what it should out of the hole. I know the converter is holding me back, as well as the stock heads and intake.
Also, it was pure murder getting that 3" tucked up in there. I am still not happy, and might take it off for a TTI exhaust this summer.
Joined: Sat Sep 23 2006, 04:30AM
Location: Sharpsburg, GA
Posts: 924
Ricky, the stock manifolds fit 2 inch pipes and the high performance factory manifolds from the later magnum and super commando engines fit 2 1/2 inch pipes.
I would call the TTI tech people and ask some questions.
Although I agree that 2.5" duals would be sufficient for a stock (even Commando/Magnum) 383, I don't see a down-side to 3" pipes. Well, except for weight and installing the things. We all know that 340's are no torque monsters, but with headers and TTI 3" H-pipes on my Valiant, the torque curve is nearly flat, with 291 lb-ft peak at the rear wheels, and over 250 lb-ft from 2000-5500 rpm. That translates to 330-340 lb-ft at the crank. If the carb is tuned to account for the better breathing, there should be no loss in low-speed torque, IMHO.
Joined: Sun Feb 26 2006, 08:46PM
Location: Kingston,Ontario
Posts: 5622
As a member who has the TTi manifold-back system in 2-1/2,it is great! As long as you provide your manifold numbers to TTI,you will be just fine. My car has a 440 with an RV cam and a few mods. After a week or two running it,tweaking clamps,and letting the muffs break in,it sounds really good-and quiet! Beautiful tone at idle. It has a snarl to it when honking on it,too! !drive Here is the thread I started about it last summer: http://www.cbodydrydock.com/forum_viewtopic.php?5.7617 !thumb !thumb
<span class='smallblacktext'>[ Edited Tue Jan 09 2007, 09:45PM ]</span>
Rick, when I went and had my exhaust replaced the flanges from my stock manifolds were actually 2 1/4. I had a local shop do mine since I am a bit !crazy and have my exhaust exiting in front of the rear tires.
Joined: Thu Dec 14 2006, 04:59AM
Location: Italy
Posts: 147
Thanks to all!!! I provided my casting #s to TTI and they said 2,5" will be right and enough!!! I am anxious to hear how will the 383 sound after exhaust replacement!!!