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Do they provide any better flow than W/Z manifolds? Not that I can see - in fact they might be worse since the W/Z actually have internally divided runners that have better flow paths instead of the square corners where these tubes join.
Do they provide any more clearance than W/Z manifolds? Nope.
Yeah, they may weigh slightly less. Until somebody shows me back-to-back dyno numbers, I say these are worthless... or worse. By the way, they are not "headers" any more than a four door Mercedes is a "coupe".
lol, I seen them last night. I was shocked at the responses being so positive. I agree that till I see dyno numbers I have a hard time believing they will help.
Good grief. I guess it depends on the size of the tubes on whether they flow well. Good for someone wanting to use their current exhaust. Problem is the wide Olds block doesn't leave much room.
Last edited by olds 307 and 403; October 14th, 2017 at 05:35 AM.
Good grief. I guess it depends on the size of the tubes on whether they flow well. Good for someone wanting to use their current exhaust. Problem is the wide Olds block doesn't leave much room.
No, actually the size of the tubes is less important than the routing. The 90 degree corners are the worst possible design. These are worse than W/Z manifolds, as the manifolds actually have internal dividers that act as individual runners. W/Z manifolds fit anywhere these do. I'll also add that you can remove and install the W/Z manifolds without disturbing the dipstick tube. These require the tube to be pulled out and reinstalled.
To be fair, the 307 was horribly restrictive compared to these, you swear they were trying to stop any hp being produced. The Mustang used tubilar manifolds, it added to potent package for the time.
Agree with the flow restriction comments here. If these were equal length shorties flowing
into a common collector (aka sanderson) then I could see a limited advantage.
Curious that Thornton doesn't have any performance data to show their worth.
Until that time, I don't see the point.
Agree with the flow restriction comments here. If these were equal length shorties flowing
into a common collector (aka sanderson) then I could see a limited advantage.
Curious that Thornton doesn't have any performance data to show their worth.
Until that time, I don't see the point.
I have not see the Thornton BBO manifolds but the SBO are a joke for performance.
I saw these last night and I applaud the thought and work that went into them but I see no advantage to using these over stock manifolds. In fact the way they are made makes me think the loss in horse power could be significant over stock manifolds. Basic physics folks.
I am just surprised that Thornton has chosen that design in lieu of perfecting the W/Z's even more... Probably just looking for a wider buyer base and/or increased application purposes...
You guys sit around and bitch because Olds lags in parts produced compared to other brands. Anybody who says they are not as good as manifolds is just guessing. They may or may not be equal or better but @ least Thornton made the effort. Just look @ a set of LS manifolds,they have a similar design and they make good power. Just as those who criticized the new BBO block by Rocket. Cost too much,can't afford it. well guys,the Olds market is very limited and costs have to be offset by volume and with tight *** Olds guys,well you know the story. I had the 66 3X2 intake crossover block off plugs made,it cost me a lot of $$$$ and I still haven't recouped my investment Maybe I will or maybe I won't but @ least I made the effort to help the hobby. Sorry to vent but it just pisses me off to see something bashed that was made to try and help the Olds hobby. Another thing,I would just about bet $$$$ they make more power than manifolds. I'll tell you something else,I know for a fact that a multi time NHRA P/S Champion experimented with square tube headers. I know it for a fact because I saw them with my own eyes.
Last edited by 66-3X2 442; October 14th, 2017 at 04:52 PM.
While I get that we should be happy for any aftermarket activity, I don't think Joe is guessing. I'd be very happy for aftermarket exhaust that looks stock but works better, however, when it's designed by someone who looked up at his shop's HVAC duct routing and decided to copy it, I don't think it will be any better at all.
I agree with you Mike,in fact I bought a set of these.
I think these are going to be a great compromise between stock manifolds and full length headers.
Added benefits of better heat dissipation,less weight and no issues with ground clearance also.
I will be eagerly awaiting Thornton to release some data from comparison dyno testing,until then,every opinion mentioned here including mine are pure speculation.
Also,I think there will be enough room to slide the header up and over the dipstick tube without having to remove it.
Last edited by w-30dreamin; October 14th, 2017 at 08:49 PM.
Joe , why would you need to pull the dip stick tube. Wouldn't the header when unbolted just lift up and over the tube? I think they have kind of a cool tough look to them. I have know idea on the performance characteristic
I think they look ok. The performance, not sure but , let me tell ya'al, the hedmann shorty headers on my 76olds 350 will blow by any chebby cruz if I'm ahead of it going down a steep hill with a good 100MPH tail wind.
PUT-R-THER, ANUF-SAID!
Joe , why would you need to pull the dip stick tube. Wouldn't the header when unbolted just lift up and over the tube? I think they have kind of a cool tough look to them. I have know idea on the performance characteristic
Yeah, maybe. I'm used to full length headers where that isn't possible.
Still don't like em. I do appreciate the efforts made to help our hobby though and would like to see dyno comparisons on these manifolds.
I'm also a big fan of Thornton.
As for the Rocket Racing block, I love that and it may come down in price as more are sold. A lot of new products start high to pay for research and development.
They do look well made and intro price is fair. Just like the Thornton SBO manifolds as well but with Olds wide block and working like stock severly limits any manifold or header. I have Sanderson shorty headers and love the ground clearance gain but the only collector gaskets that any amount of time is the MLS, aluminum or Copper. I have to double up the collector gasket on one side, still have a slight leak. I figured for what maybe a 5 hp loss compared to the low hanging Hooker Comp headers, it was worth it for me I would love to see a back to back comparison between stock low po manifolds, Thornton maifold, tube when they come out, sb shorty, cheap full length and ARH headers. I still say the Small Block Dodge magazine dyno on a 300 hp Magnum crate motor is relevant. Starting with terrible 318 Truck/Van manifolds, very restrictive to fit in the van, I had to swap the car manifold on one side to fit a 318 from car when I blew the 318 in my 77 Dodge Van. They gained 11 hp, similar torque on all tests as well with 360 manifolds, 14 hp with 340 Hipo manifolds, 21 hp with shorties and 28 hp with stepped full length headers. I am swapping a RPM intake and 1.72 true roller rockers in place the factory no adjustable. Who knows if I will see anywhere close to the 30 hp the magazine's claim. Just using parts from my shelf and hoping for seat of the pants and a high 14, mid 9's in the 1/8 track run. Glad Thorton is making us stuff, especially for the ignored and very underrated SBO.
Last edited by olds 307 and 403; October 15th, 2017 at 06:46 AM.
The folks who think these are worthwhile have apparently never actually taken a close look at the factory W/Z manifolds. The factory manifolds have internal individual runners and smooth turns to minimize flow disruptions. That is much better for exhaust flow than simply joining the tubes at 90 degree angles. The LS tubular manifolds mentioned above do NOT look like these. They have smooth transitions, correct radii, and have been flowed by the factory in numerous tests. As for the aftermarket supporting Oldsmobiles, I have a hard time understanding how selling a crappy product helps anyone other than the person who is making a profit off of uninformed buyers. It would not have been difficult to make these manifolds (they are NOT headers) flow better. Doing so would have increased production costs. Apparently someone did an analysis to maximize profits, not performance.
Joe,thanks for all the info,I have always highly valued your opinion and info.I have learned and used much of your info over the years.
I'm hoping Thornton hurries with it's test data so this debate can be brought to rest with fact.
October 14th, 2017, 04:17 AM
