Will SSI's make more HP than Thermal reactor headers?
 

Does any one have any numbers to show if SSI's make more HP than regular '76 HE's on a 2,7 with thermal reactors replaced with the short headers? I took the thermal reactors off my motor and replaced them with the three pipe Sebring header, but now I am thinking the SSI's would be better. I have heard 10-15 hp, but I am not sure if that is compared to a motor with thermal reactors or not. Be nice to know before spending all that money.

Thanks

Have 1976 2.7 ,had sebring three pipe to thermo heat exchanger stock muffler that worked very well through low rpm/ throught 4800 rpm good accelaration to red line .With SSI /stock muffler 2 in 1 out about the same noise level at 1000 rpm motor comes on with a bit more power at low to mid then pulls real strong till red line . And the heat really works with SSI . Its real nice to have heat in pacifc north west! PS SSI are a piece of art work real craftsman ship .One thing the thermo ex flange thickness / thick around 3/4 " and make sure the SSIs dont have the protuding ring in flange to head mounting surface / 3 liter has protruding ring 2.7 will not accept this ring check with pelican sales staff on this . Im real happy with SSIs !

All things being equal, yes. SSI's are worth about 10 HP over the OEM '76 HE's & thermal reactors; more with a sport muffler.

But with stock 76 HE's and the thermal reactors replaced with Sebring headers are the SSI's still worth another 10HP ?

On my California delivered '76 911S I went from the three-to-one Sebring "headers" (calling them headers is a bit of a stretch if one means equal length, tuned headers) and '76 OEM California air boxes to SSIs. I reinstalled the stock muffler. Comparing the Sebring "headers" and the original thermal reactors (I still have them) led me to conclude in terms of gas flow there wasn't much of an improvement - the Sebrings just didn't collect and store as much heat as the insulated thermal reactors. I didn't dyno the car afterwards but there was a noticeable improvement - especially mid-range (3500 RPM) and up. I would estimate a gain of 7 to 10 horsepower at my altitude: 6000 to 7000 ft.

Yessir,...indeed they are. If you install the SSI's, you will need to adjust your CO.

Any thermal reactor exhaust needs to be consigned to the dung heap.....

Stock HEs or SSIs will allow for a better running motor.