Moparts Tech Archive

Exhaust

Big Block Street Headers for B & E body Mopar Applications:

This document outlines the choices available in as much detail as possible, short of actually trial fitting each one on a car. “Street” header is defined here by having a 3” collector, not 3-1/2” or larger. The research is skewed towards compatibility with modern aluminum cylinder heads with angled plugs (Edelbrock, Bulldog, and Indy). It is noteworthy that Indy heads have raised exhaust ports (except EZ models), so the headers discussed here would only be applicable to Indy-lowdeck (B) combinations (383/400 blocks). Hedman makes headers specifically for Indy-highdeck combos. The only aftermarket heads with straight plugs are from Mopar Performance, namely the Stage VI and the 383/440-replacement head. Even if your current heads don’t have angled plugs, it makes sense to purchase headers that work with them just to keep your options open in the future. Headers being evaluated are:

Hooker - #5903, #5111, #5101
Hedman - #78030, #78036, #78038 Elite
DynoMax - #85034, #86034
FlowTech - #13130FLT, #33130FLT
Doug Thorley - #151, #151-C, #152, #152-C

The biggest surprise was that all headers, OTHER THAN HOOKER, have the same basic primary pipe routing, both for the driver and passenger side. That is, the front-most pipe (#1 and #2) all route over the center pair of pipes, and come down between them and the rear-most pipe (#7 and #8). The #7 pipe on all these headers are bent back dramatically to offer starter access once the steering column has been removed. As far as I can tell, Hedman, DynoMax, FlowTech, and Doug Thorley headers are ALL compatible with angled plug heads. Their configuration almost exactly mirrors that of the much-touted $800 (coated) TTI headers, which seems to be the benchmark. In terms of construction, the Hedman #78038 Elite and the Doug Thorleys use heavier 14-gauge tubing, while the others use thinner 16 or 18-gauge. Here’s another surprise…the DynoMax and the FlowTech headers are the SAME EXACT header. The quality of the work on the port flanges was downright awful on the ones I looked at.

Hooker headers are another matter. It seems that NONE of Hooker’s designs are compatible with angled plug heads. I can speak first hand about the Competition #5903 model as I have them on my car. There is no way an angled plug would work on #4 or #8. It should also be noted that the passenger side #5903 and #5101 are the SAME. In addition, the driver side #5903 came in contact with my power steering box, steering column, and torsion bar. The pipe routing on the driver side #5111 and #5101 are nearly the same and will create an issue on #3. Further evidence of these problems comes right from the Hooker catalog, in footnote #200, stating that they don’t work with B1 heads because of their angled plugs. For those who don’t recall, B1 heads were the first performance head for big block Chrysler introduced in 1986. Perhaps Hooker only mentioned the B1 because they were the only angled plug heads available when the footnote was written. This note appears on the #5903, #5111, and #5101 and even their big-boy #5209.

So how do they fit? Since I haven’t actually installed these headers (other than #5903), it is somewhat difficult to determine. However, I do have some data that most others do not: return rates. Mind you, most people buying these headers are installing them on iron heads. There is also no way to tell how many customers just broke out the hammer when they had fitment issues rather than returning them. Listed below is the percentage of returned product of both painted and ceramic-coated headers from January 2003 to July 2005 at a large performance parts distributor:

Hooker Competition - #5903HKR…4.8%
Hooker SuperComp - #5111HKR, #5101HKR…10.0%
Hedman - #78030, #78036, #78038 Elite…8.7%
DynoMax - #85034, #86034…12.0%
FlowTech - #13130FLT, #33130FLT…insufficient data
Doug Thorley - #151, #151-C…4.4%
Doug Thorley - #152, #152-C…2.9%

So who makes the best street header? In my opinion: Doug Thorley. Why?
For 3 reasons.
1) They are the only header manufacturer other than TTI offering both lowdeck (#151) and highdeck (#152) versions.
2) Subjectively speaking, the bends in their headers appeared tighter than the rest.
3) The ultra-low return percentage. The second best choice would probably be the Hedman #78038 Elite, which has a 6.3% return rate when measured separate from the standard Hedman models. So how much cheaper are Doug Thorleys than a set of TTI headers? About $300…enough to buy a nice pair of 3” mufflers and an X-pipe.

Ed Leung
Summit Racing Equipment

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