This has probably been asked before, but how much difference do hedders really make on a BBC? I am thinking of putting 1 3/4 long tubes on my 69 to squeeze a little more out of it in the 1/4 mile. What brand are your favorites?

the best I ever got out of mine with Hooker 2"/3.5" comps was 12.04...that was in good air late november...switched to 1.75"/3" coated Dynomax and have recorded several sub 12 second e.t.s. with an 11.85 last summer on drag radials in july and a best of 11.78 on slicks.

Big tube hedders work great with huge heads,cam,carb intake, otherwise they hurt performance.

BB485, Mark is specifically asking about using 1-3/4" headers. That is not a big tube header - should work great on his '69.

Mark if you are running factory cast iron manifolds currently, then you will love the power boost from 1-3/4" long tube headers.

As Robert points out, even a lot of modified big blocks love the 1-3/4" size. I'm running 2" primaries on my 496, but I kinda think it needs them smile.gif

Thomas

I think in your case the inexpensive Dynomax or Summit brand fit well. Use them! If you wanted to get trick about it, think about a Heddman X pipe 3 x 2.5 and splice the whole thing into your current system using flanges.

On and off the subject, how much of a different between cast BBC manifolds and a 1 3/4" tube 'shorty' headers?

Gotago I just installed a set of heddman elite 1 3/4 coated headers on my 408 BB. They fit perfect no modifications at all. Did not have to lift engine to install slid right in from the bottom. Feels like I picked up 20-30 HP and tire roasting torque graemlins/hurray.gif
Gary

I've got to agree. I just put Hedman's in my '67 this past weekend. I didn't have to make an mods. 2" tubes. part #66002 with HTC coating for around $369.00 from Jegs.

Thanks for all the replies. I think I'm gonna go with the Hedmen Elites. Again, thanks for all the opinions.

Yes definitely proper sized headers will make a huge diff on a BBC or most any motor I would not look for brand but dimensions and yes the better designed header will not always be the easiest to install
I agree smaller is bettter on NA motors ....if you talk to the true header engineers ( Jere Stahl ED Henneman sp?etc.) and assuming you installing headers for performance when open at a track primary pipe OD is very important but one of the most overlooked dimension is Collector diameter!!! ...most if not all name brand headers typically come with too large collector diameter and if they offer different diameters usually in 1/2" increments too large should be 1/4" increments to trully tune for best HP...and of course "equal length "at least 34 " and could go to 36-37" which has just about disapeared from store bot headers nowadays .... for a street car with full exhaust this not as critical but for open header drag racing a good header mfg will want to know horsepower and max rpm and adv. cam duration .you did not provide any of that info ...based on a formula I have (actually a chart for dummies like me ) my engine builder gave me from one of the above mentioned header " engineers he swears by , a typical BBC making 380-500 flywheel HP will et the best in a car weighing aprox 3700lbs with 1 3/4 " primary tubes with ...are you ready ....2 3/4" collectors for best bottom end mid range power .....3" OD would be max for some lighter cars
480-580hp comes out at 1 7/8" with 3" collectors
560-660 hp 2" 3 1/4"
.... try and buy equal length 1 3/4 headers with either 2 3/4 or 3" od collectors !! it's really a shame better stuff not out there cause custom stuff is not cheap ..
. I have an old set of BBC headers bot in 1969 .do not remember brand I do remember paying 75.00 for them .... 2" od all tubes within 1 1/2" of 35" long ..and 3 1/4" collectors !!!! I bot them for my stock 396 66 so primary tube too big but interesting how close to equal length they are and the 12" long 3 1/4" collectors

Alot here have been buying Flowmaster addon so called " merge collectors" for their existing headers and getting good results ..... I have a set for 2" od that I have never used interesting to note they are 3 1/4" OD I wonder what OD the ones for say 1 3/4" primary pipe version is

Joined my engine builder a while back when he dyno'd a truck pull monster BBC the headers where the customers big pipe upswept ones you see from Hooker with removable collectors when the collectors were removed.just 4 single pipes the change in HP was almost nothing like 8hp or something ...how effective do you think those big OD collectors were ...needless to say he convinced the customer to get some more advice on proper header sizing .... alot of his sbc hobby oval track motors around 400hp make the most power with 1 5/8 tube size with 2 1/2" collectors
FWIW ... maybe nothing you decide, just thought I would share what I have found as I shop for new headers for my new motor.
Bill

Bill,
Thanks for the reply. My motor is a 408 with a comps 268 cam and 215 heads, maybe close to 375 HP. The Hedmans are advertised with a 3 inch collector and 1 3/4 primary tubes. I was toying with the idea of going with 3 inch pipe from the collector to the muffler and then reducing it to 2.5 inches at the muffler. My reasoning is the exhaust will have cooled enough by then to pass through the mufflers easily. I don't have much experience with HP motors so I may be way off base with this one. Again, thanks for the information.

Based on whats available off the shelf, and your 375hp estimate your looking good IMO and yes your exhaust sizing follows the theory ... if you wanted to get really anal and maybe pick up some et .try and find someone to make some collector reducers to bolt on to your current collector from 3" tapering down to 2 3/4" about 10" long .at the track when open cut the tapered collecter just before the hot spot ends and then use 2 3/4 pipe to the mufflers ...yes definitely 2.5" tailpipes