Exhaust Syst. Suggestions: 302/4spd Toploader?

[68Blue302Coupe]

Hey all,

I have a 302 with a 4speed Top Loader and am looking to replace my poor-fitting Tri-Y headers and possibly the whole system and would like some suggestions. Does anyone have a set up that works without modification (i.e., bolt-on)?

The Tri-Y's had major clearance problems with my starter and bell housing and had to be crimped. Problem now is that (I think) the crimp basically restricts the flow and limits the gain from running headers. I have not finishing install my clutch linkage (stock Z-bar set up) but am anticipate fit issues with this as well.

I was considering just going with the Hi-Po manifolds but understand that requires a different Z-bar? I really don't want to change the linkage if I can avoid it.

Anyone have the 302/4spd TL/stock z-bar linkage? What exhaust system are you running?

Thanks!

 

[2+2GT]

I have a 302 with a 4speed Top Loader and am looking to replace my poor-fitting Tri-Y headers and possibly the whole system and would like some suggestions. Does anyone have a set up that works without modification (i.e., bolt-on)?
Yep- The GT exhaust with HP manifolds.

The Tri-Y's had major clearance problems with my starter and bell housing and had to be crimped. Problem now is that (I think) the crimp basically restricts the flow and limits the gain from running headers. I have not finishing install my clutch linkage (stock Z-bar set up) but am anticipate fit issues with this as well.

I was considering just going with the Hi-Po manifolds but understand that requires a different Z-bar? I really don't want to change the linkage if I can avoid it.

The HP pipe and manifold are below the equalizer, not above as on the standard. I was in your boat when I switched, but some blowtorch and hammer work and my former standard equalizer now clears. Barely.

The rods are the same either way, but the true HP equalizer requires a different engine pivot, too. If you switch, it's about $135 for the needed new parts. If you're handy, then no problem.

Here's the difference:

Std:

HP:

 

[68Blue302Coupe]

Thanks for the info! So the stock GT exhaust + HP manifolds will bolt right in? That sounds like a good option. What kind of clearance do you have around the bellhousing with that exhaust? With the z-bar, those two don't look too different, I bet I could get mine to clear the same way that you did.

 

[2+2GT]

Bell clearance with the HP is actually a bit better, because the manifold outlets are lower, particularly on the LH. The tightest spot is the LH pipe coming off the manifold, the lower arm clears by about 1/4", the arm actually wraps around the pipe.

 

[68RCodeConv]

I have 289 HiPo exhaust manifolds on my 67 GT350. I bought the dual exhaust system sold by NPD for this application. It bolted right on and fit very well. You will have to do a LOT of test fitting (especially on the tailpipes) before you get it lined up properly. I put never-seize on all the joints to enable me to twist them easier while test fitting.

I do recommend that you have the joints welded after installing it because they all leaked on mine even after tightening the muffler clamps.