Sdmodified

iTrader: (1)

This is a much needed option for our cars. I would be very interested in a 3” version of your exhaust for sure!!

toddoky

There's been no mention of it from Holley management, but I would be game to tackle it if I were told to do it. A critical issue would be deciding which aftermarket K-member to use to develop the headers for use with as there's no chance of the stock K-member accommodating a header of that tube diameter.

Chuck!

BMR. You can send me the first set. Sounds good, thanks ha!

Sdmodified

iTrader: (1)

That seems very involved. However, building a 3" version of your dual exhaust should be straight forward! I think the only additional item needed would be a panhard relocation kit and they are pretty much all the same... Would be great to have this 3" version ready to ship by spring! Wink, wink

Clemson327

iTrader: (4)

Hi @toddoky I know the system wasn’t explicitly designed for it, but I’m planning on using this crossmember to gain more exhaust clearance for my y-pipe with a Gen I/700R4 combo. I’ve calculated that the 700R4 mount pad will be 0.46875” closer to the front of the vehicle than the trans mount pad with the intended LS1/4L60E combo. I’m planning to either use an adjustable trans mount with the 71223003HKR adapter or have an adapter fabbed up, but I’m not sure about the height.

TL;DR, do you know if the transmission mount pad is the same distance from the output shaft centerline between the 700R4 and LS1-4L60E transmissions?

toddoky

The distance to the trans mount mounting holes from the bellhousing mating plane on the common LS type 4L60E is 24-3/8" and the distance from the output shaft centerline to the mount attachment plane is 2.688". The stock trans mount mounting holes in the 700R4 are located in the main case and are 22.275" from the bellhousing mating plane and the distance from the output shaft centerline is 2.938". If you are using the 700R4 conversion extension housing that relocates the trans mount attachment plane to the TH400/2004R fore/aft position, I can't give you a definitive answer on its geometry as I've never personally worked with one of them personally.

Clemson327

iTrader: (4)

Thanks for the quick response, and that's good to know! I've read your comments before that many sites post the incorrect mounting hole locations so I appreciate you providing the correct ones as I was using 23-19/32" and 22.5" for the two. Using your numbers brings the delta to 1.475" closer to the front of the vehicle for the 700R4 mount pad, and the centerline distance delta means that the adjustable mount is almost perfect with a height of 1.75" vs the stock 1.931" (per others on this board), meaning that my output shaft will be 0.069" higher than stock which is a minimal angle change at that distance from the motor mounts. I'll be adding an adjustable torque arm at the same time and an angle finder to ensure that the U-joint angles match at each end of the driveshaft.

I'll post pictures on here as I get further along to give others an idea of how they could integrate this crossmember with different combinations.

Louis Q

any news on those ? i was looking on holley web site today and can't find them

Bonjorno

Hey guys, I'm looking to use this exhaust on my 87 trans am gta, I know it's not designed for my 700r4 transmission.

But I was wondering if anyone can tell me if there are any headers that would direct bolt a 350 tpi to this exhaust, if not can anyone recommend a certain header for my engine that would provide the closest fitment possible ? Or any other parts I could get to make this modification as easy as possible ? Thanks guys.

ShiftyCapone

iTrader: (7)

From the posts above it sounds like Hooker will have their SBC headers any time now, which will bolt directly up to the dual exhaust.

Bonjorno

Has anyone heard any updates on the ETA for these headers ?

89formula350b2l

iTrader: (11)

Interested and subscribed