Emergent request for Hooker Header Install GT500

[shelbydoug]

Holly gitski's Batman! My meds must be wearing off. Only you guys can find issues like this. Meds. MEDS! GIMME MY MEDS! 

[427heaven]

I have them on my 67 with a 427. Both holes per port are verticle and work great. I have them on my 68 cj with 16 possible bolt holes to use they also work great. As long as you can get some holes across from each other like the gt 390 heads you will be golden. Hope this helps-

[Bob Gaines]

The Hookers have 4 hole flanges on each cylinder flange. They will fit all 390 427 428 configurations that's what makes them nice. No they are not original and take some extra effort to install but your stockers wont be a cake walk either. Good luck on what ever direction you choose.

I guess our biggest concern is that...although yes they have 4 hole flanges, they aren't designed to accommodate offset configurations like the stock 428 heads. Under this setup, two of the upper holes can't be used without additional fabrication. My biggest question is really whether people have continued to install them without modification and only use 2 of the 4 upper holes in offset configurations.

Our assumption is this would compromise proper fitment as two of the flanges wouldn't be fully secured at the top. But, if people have continued in this fashion and not had issues, we are happy to try it.

Hooker does not make a setup from the factory designed for the offset bolt holes unfortunately.

Remember Randy's suggestion of elongation the hole of the header flange on the ports with the offset bolt hole. That way they will fit the pattern and you will have the extra clamping force for a good seal. Also not mentioned but just to make sure you are aware that you will have to run a special powersteering bracket to relocate the powersteering ram down lower to clear the headers. Also plan on test fitting and removing to modify with some well placed ball peen hammer hits for clearance before final install . If you don't have to more power to you . The headers can be very close to the shock towers even to the point of contact. Best to do the pre fit first before painting.  If you decide to run the stock manifolds it is even more important to have the ports surfaced so that they are all flat in the same plane. From the factory there is no exhaust gasket used so a flat surface insures a good seal . I always smear a thin coating of orange high temp silicone before bolting on the cast iron manifolds . I don't put much on and if any little bit squeezes out I can take a razor blade and pick it off. Don't forget a good high temp cast iron paint for the stock manifolds .You don't want to skimp like with a inferior VHT rattle can product because you only want to do this once.  Best of luck what ever you decide.

[dabigpud]

The Hookers have 4 hole flanges on each cylinder flange. They will fit all 390 427 428 configurations that's what makes them nice. No they are not original and take some extra effort to install but your stockers wont be a cake walk either. Good luck on what ever direction you choose.

I guess our biggest concern is that...although yes they have 4 hole flanges, they aren't designed to accommodate offset configurations like the stock 428 heads. Under this setup, two of the upper holes can't be used without additional fabrication. My biggest question is really whether people have continued to install them without modification and only use 2 of the 4 upper holes in offset configurations.

Our assumption is this would compromise proper fitment as two of the flanges wouldn't be fully secured at the top. But, if people have continued in this fashion and not had issues, we are happy to try it.

Hooker does not make a setup from the factory designed for the offset bolt holes unfortunately.

Remember Randy's suggestion of elongation the hole of the header flange on the ports with the offset bolt hole. That way they will fit the pattern and you will have the extra clamping force for a good seal. Also not mentioned but just to make sure you are aware that you will have to run a special powersteering bracket to relocate the powersteering ram down lower to clear the headers. Also plan on test fitting and removing to modify with some well placed ball peen hammer hits for clearance before final install . If you don't have to more power to you . The headers can be very close to the shock towers even to the point of contact. Best to do the pre fit first before painting.  If you decide to run the stock manifolds it is even more important to have the ports surfaced so that they are all flat in the same plane. From the factory there is no exhaust gasket used so a flat surface insures a good seal . I always smear a thin coating of orange high temp silicone before bolting on the cast iron manifolds . I don't put much on and if any little bit squeezes out I can take a razor blade and pick it off. Don't forget a good high temp cast iron paint for the stock manifolds .You don't want to skimp like with a inferior VHT rattle can product because you only want to do this once.  Best of luck what ever you decide.

Everything else is ready to go. Had the heads resurfaced earlier this week to ensure proper fitment.

Already made sure to have the drop down bracket as well. Thanks for the suggestions.

We will likely just drill out new holes on the headers to "ovalize" the two offset ports.

[427heaven]

All of those items should help put a smile on your face when completed.

[shelbydoug]

The point is, get two bolts on per port IF you can. The nature of the headers is that they will warp enough with heat cycles that it is common to the point that you may not be able to eliminate all of the leaks.

[427heaven]

ALWAYS RUN HEADER GASKETS... ALWAYS-   FOR IMPERFECTIONS IN SEALING SURFACES.

[shelbydoug]

The Hookers have 4 hole flanges on each cylinder flange. They will fit all 390 427 428 configurations that's what makes them nice. No they are not original and take some extra effort to install but your stockers wont be a cake walk either. Good luck on what ever direction you choose.

I guess our biggest concern is that...although yes they have 4 hole flanges, they aren't designed to accommodate offset configurations like the stock 428 heads. Under this setup, two of the upper holes can't be used without additional fabrication. My biggest question is really whether people have continued to install them without modification and only use 2 of the 4 upper holes in offset configurations.

Our assumption is this would compromise proper fitment as two of the flanges wouldn't be fully secured at the top. But, if people have continued in this fashion and not had issues, we are happy to try it.

Hooker does not make a setup from the factory designed for the offset bolt holes unfortunately.

Remember Randy's suggestion of elongation the hole of the header flange on the ports with the offset bolt hole. That way they will fit the pattern and you will have the extra clamping force for a good seal. Also not mentioned but just to make sure you are aware that you will have to run a special powersteering bracket to relocate the powersteering ram down lower to clear the headers. Also plan on test fitting and removing to modify with some well placed ball peen hammer hits for clearance before final install . If you don't have to more power to you . The headers can be very close to the shock towers even to the point of contact. Best to do the pre fit first before painting.  If you decide to run the stock manifolds it is even more important to have the ports surfaced so that they are all flat in the same plane. From the factory there is no exhaust gasket used so a flat surface insures a good seal . I always smear a thin coating of orange high temp silicone before bolting on the cast iron manifolds . I don't put much on and if any little bit squeezes out I can take a razor blade and pick it off. Don't forget a good high temp cast iron paint for the stock manifolds .You don't want to skimp like with a inferior VHT rattle can product because you only want to do this once.  Best of luck what ever you decide.

Everything else is ready to go. Had the heads resurfaced earlier this week to ensure proper fitment.

Already made sure to have the drop down bracket as well. Thanks for the suggestions.

We will likely just drill out new holes on the headers to "ovalize" the two offset ports.

Drilling ANYTHING into the header flanges WILL compromise the sealing capability of the header flanges. You WILL be creating problems that did not exist before.

Just get two bolts per cylinder in. It doesn't matter which two.

Other then that, do what you want to BUT if you didn't want the advice, why do you ask for it?