We tore apart Mark's (914Rubber) drive train. I'd never even seen a set of 75-76 HE's before. It seems to have all kinds of extra vent holes. Can someone use these pictures and let me know which ones should be here, and which ones aren't.
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The sheet-metal should fit tight around the exhaust pipes.

The 75/76 HEs don't flow as much exhaust as the earlier 2.0L HEs or the SSI 1.7/1.8 or SSI 2.0 HEs.

Get some good SSIs and a new muffler, you'll have a little better engine performance and great heat.

Jim

there should be NO vent holes except for inlet and outlet. the vent holes you see are wear thru holes, etc. those are pretty shot for HEAT purposes. but for exhaust they are fine, though they flow the least best of the other stock options.

Ive seen worse.
Blast them clean weld or braze the box ends to the tubes & I used some muffler tape on wear-thru holes.
Converting to early setup is preferred but means sourcing a bunch of different items, tin, hanger muffler ect.

Just collecting info for Mark. He'll make that call. I know he'd like to keep it 75-76 and keep his dual out triangle flange Triad muffler.
When I setup to blast the heat shield I'll clean them up. I think Mark has a TIG guy that could weld them up.