Ray said:
FWIW, Here are some general rules of thumb regarding headers as proven on countless dynos:
The tube diameter determines the rpm of the torque peak. Larger diameter = higher rpm for the peak.
Tube length determines the torque shape on either side of the peak. Longer tubes favor the torque below the peak and shorter tubes above the peak.
The collector diameter and length has the same impact as tube diameter and length.
The impact of Tri-Y and step tube designs is greatly influenced by other parameters in the combination. They could help the mid range or not have any significant impact.
The TTIs are GREAT street headers, and arguably the best street header as far as their fit and delivered performance. If you're building a drag car there are better options. They are also a little pricey - but like everything in life you get what you pay for..
sam z said:
Droptop I like that.
Mcmopar - you sound knowledgeable about the TTI's. What's the big advantage? Do you have them?
Ray is right on the money. tti's are great street headers but do not have equal length tubes. This will make them less effective on the strip but you won't notice it that much on a street car. If you are a serious racer then Hooker headers are a fine choice. I went with the 1-7/8" tube diameter after consulting with tti on my engine/drivetrain combo. Since my engine was modified with a healthy cam, compression ratio and induction system they recommended a bump from the standard 1-3/4" primary tube size up to the 1-7/8" diameter. A stock or nearer stock 383 is recommended to use the 1-3/4" primary tube size.
Sam - yes I have the tti headers. I bought them back in '03 after trying 2 sets of Hedmans that were, by admission of their own engineer whom I spoke with on more than one occaision, manufactured incorrectly. They would not clear either the standard nor mini starter as one of the tubes was in severe conflict with either starter.
Well, I decided to pony up and try the tti's since I had been reading about them in the various Mopar mags. They were expensive, but as Ray so succinctly observed "you get what you pay for". I also ordered the full tti 3" exhaust system with H pipe and got my Magnaflow mufflers from a place in Canada. Surprisingly they had the lowest price of any domestic suppliers. Go figure.
When moparmoose3 (Jerry) and I went to install everything we lifted the car up on jack stands all the way around and put the headers in from the bottom. I removed the spark plugs but left the manifold studs in place. The instructions mentioned that the engine might need to be lifted by 1-1/2" or more but we decided to try installing the headers without lifting the engine. We tried the driver's side first since it was a tighter fit over there. I as under the car trying to get them to fit and Jerry was up in the car (he has a bad back and we didn't want to have him all stove up - he helped a lot with disassembly though). The headers would only go so far and then they would hit something - which after a quick check turned out to be the pitman arm. We were chatting about it and Jerry all of a sudden said "wait a minute!" and turned the steering wheel all the way to the right - which moved the pitman arm all the way to the left. When he did that the header slipped right up into place as sweet as could be! We then proceeded to the passenger side and he turned the wheel the other way and the header went right up as pretty as you please. All told, even with the bit of trouble on the driver's side, it took no more than 1/2 hour to 45 minutes to get the headers in place and bolted in. No dinging, no swearing and no bruised knuckles! We then installed the rest of the exhaust system and Jerry just could not believe how easily it all went in. He had put Hooker Super Comps on his '66 Coronet with a 440/727 prior to my installation and it was an all-day affair.
The 383 4 speed installation was very easy but minor mods need to be made to the automatic linkage for 727 equipped cars IIRC. Their website gives all the pertinent information.
Overall I've been extremely pleased with my tti's. They are made well with 3/8" flanges so they don't warp and they provide excellent gaskets that don't burn through. Yes, they are expensive but IMO they are well worth the $$$.
How they would do with a Hemi I have no idea but if their 383 headers are any indication I would think they would be easier to install than just about any other header on the market. As for the 440 - well you may need to jack the engine up a bit since the 440 is a bit wider than the 383 but I think it wouldn't be all that much more difficult than my installation - especially with a 4 speed.