RX3 vs' Racing Beat Headers
 

Hi Guys,

Looking for experiences with Racing Beat headers in an RX-3 application.
I will be running a rebuilt 12a twin dizzy engine so I know I will need to slot the mounting plate as a minimum. (Mounts for the TD are different to any other 12a)

As this car is likely (hopefully) going to do a bit of show duty I was hoping to use a pre-made header to take advantage of the finish supplied by Racing Beat.

I was planning to use twin pipes to the diff but would consider a single pipe if I had to. That said I suspect the streetable header just has a collector added so the clearance under the firewall is likely no different.

Speaking with Jim at Racing Beat he recommended the 74-85 Disassembled kit which would mean I would need to get the header finished after building. At the time he was not sure if the 74-85 per-assembled kit would fit.

So my question is has anyone tried fitting the 74-85 road race kit to an RX-3 - If so were any modifications required and were there any clearance issues.

Streetable Header for 74-78 12A Engine - RX-2, RX-3 - Racing Beat
Road Race Header for 74-78 12A Engine - Racing Beat

All advice appreciated.

If i recall correctly, the twin dizzy has a different flange bolt pattern verse the later single dizzy motor... I.E. the the upper studs are closer to the lower studs.. see the twin dizzy housing on the left and the single dizzy housing in the center... i believe the studs are about 1/4 inch closer together. I am sure the newer header could be easily modified to work on the older housing


http://img853.imageshack.us/img853/3600/img0926xw.jpg

Thanks buddy,

I was aware I was going to have to slot the mounting holes in the flange as a minimum. My concern is more around clearance on the engine bay and where it bends down underneath the car - Evert installed one on an RX-3?

using a RB 13-B FB dual exhaust header on RX-3, I ran with issue with one of the pipes (rear rotor housing) not clearing the idler arm. A single outlet header worked and gave me approx 1" clearance and I chopped the section where the two pipes merge to make it a dual.

Since you have a 12-A motor, I believe you will run into the same issue.

Hey Wackey,

I was hoping you would chime in on this one, It was around the idler arm area I was expecting the trouble, A question if I may. You mentioned a single outlet header worked for you and gave you the precious inch of clearance, Was the alternative header the racing beat streetable header? Streetable Header for 74-78 12A Engine - RX-2, RX-3 - Racing Beat - I looked at this one also but thought it was probably the road race header with a collector rather than the dual pipe flange and therefore would not give me any more clearance. Racing Beat does not have the dimensions available so I am flying blind. If this is the one you used (albeit the 13b model) I would be happy to do the same modification back to dual pipes. Let me know, I really appreciate your feedback!!!

if a header is built for a RX-3, it will work whether it is streetable or road race, outlet faces towards the tranny, pipes are at least 2" away from idler arm. i have an old 13-B header on my other RX-3, built by RE not RB.

If FB 12-A header streetable single outlet is used on a RX-3, it will clear the idler but you have to unbolt it during installation/removal of header. also you will notice that the header runs straight/parallel to the frame but the oulet can be modified or turned away from frame by any muffler shop. I went this route as Ive collected several FB headers and Im too cheap to buy a new one from RB.

No Problem with Clearance, with any of the two, I am running the single with a 13B on my 77 RX3SP, Racing Beat also told me to buy the broken down pipes but I don't have time to waste on putting it together. I went with the 2 1/2 opening and pre silencer.

Thanks for the advice guys, really appreciate it. I will likely go down the same route as Wackey. Eg go for a single outlet and convert back to twin pipes.