I have been running TA's 1 5/8 headers for years, no issues. Im considering their 1 3/4 headers for my new combo. Anybody else using the Super Competition headers? My theory for wanting larger tubes is I have more compression, and when the aluminum heads come out I don't want my smaller header tubes being a possible choke point.
Not Buick but on a 406 SBC we dyno'd 440hp/506tq on 1 5/8" headers, then just for the sake of comparison we added a pair of 1 3/4" headers that had straighter tubes and only gained 5hp at peak. The heads on that particular engine flowed 269@.500" lift and the cam was .547" at the valve. Cam was a hydraulic roller. Not worth the expense of changing the headers IMO.
Mark, didn't you have like .060 off block & another .060 off heads on last build with hypers? You probably had same or more compression than you're going to have?
If you swap in a set of solid roller lifters the bigger headers might help out in the higher above 6,500 RPM range? Other than that with only 355 cubes or so and RPM limited with a hyd. cam, the bigger headers prolly won't gain you enough to justify the cost vs the headers you already have. Probably would be a good swap for a solid roller 370 stroker sbb with heavily ported heads though. The more A/F in the more exhaust out.
It was .050 off the deck of my other block, Im using the same heads that have been cut .030 I'll probably use my existing headers, was just wondering if I'd pick up like another 100 hp using bigger ones, LOL, just kidding I'd better pop wheelies once the aluminum heads come out tho
Ground clearance is good the only place that was close was the passenger side at the frame I had to move the line that was there, almost up against the frame there, got about 1/4 " They looked real nice after the Jet Hot coating. The bottom header and the Jet Hot one the last pipe #8 is the one that got close to the frame. The only place that scraped was at the collector and it just did this once in a while in low areas on back roads or driving thru the lawn. My car is lowered some. They been on there 25 years now. They don't look as nice got some rust but all in all not too bad.
Note:If you radius all the sharp edges e. g. the exhaust port flanges( any right angle cuts) the coating will adhere better.The coating thins out on the sharp edges.
Mine are also close to the brake line on the passenger side frame. I moved it the best I could and wrapped the line to be safe and haven't had any ground clearance issues.
Im just degreasing 'em, scuff em with a red Scotch Brite, clean again, then maybe a light coat of wash primer, then high heat stainless paint or something. Did the same thing with my old headers back in '95 and they lasted, still in good shape actually, no rust, I used Seymours high temp cast blast. The coatings are neat, but too pricey for me, I'd leave 'em raw if I could, I like that look.
There steel tubes that rust, leak, and fit like ****, that we put on to skin our knuckles and cuss trying to get the bolts in
