Leave off that piping.
I made a pair tube block off plate from a Simpson Strong Tie wire shield from Home Depot (56 cents).
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http://www.mazdatruckin.com/vBulletin/photoplog/images/37/medium/1_Simpson_strong_tie_wire_shield.jpg[/img]
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http://www.mazdatruckin.com/vBulletin/photoplog/images/37/medium/1_Mazda_B2200_Pair_tube_block_off_plate.jpg[/img]
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http://www.mazdatruckin.com/vBulletin/photoplog/images/37/medium/1_Mazda_B2200_pair_tube_block_off_in_place.jpg[/img]
I later removed those bolts and used the original mount assembly which also mounts to the engine.
Here's the engine after photos. I used 14mm x 1.5mm wheel lugs lug nuts from O'Reillys ($4.99 for four) to plug the pair tube outlets coming out the upper manifold heat shield.
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http://www.mazdatruckin.com/vBulletin/photoplog/images/37/medium/1_Mazda_B2200_engine_after_removal_of_pair_tubes.jpg[/img]
[img]
http://www.mazdatruckin.com/vBulletin/photoplog/images/37/medium/1_Mazda_B2200_engine_after_removal_of_pair_tubes2.jpg[/img]
Autozone has most of the gaskets, if you know the part numbers. I used Never-Seize lubricant on most of the threads;
Pre-converter gasket (top of front converter) - FEL-PRO Part number is 60534
(Special order Autozone $3.99)
Bottom gasket (3-hole) Fel-Pro 60286 (stocked at Autozone $3.49)
Exhaust pipes, second converter, muffler, etc. (need three or four) – Fel-Pro 60620 (2 stocked at Autozone, $2.99)
Pair tube gasket NAPA EXH 31548 Walker 31548 (special order – at NAPAonline.com) [url]
http://www.napaonline.com/Search/Results.aspx?Ntt=exh%2031548&Ntk=Keyword&N=599001+101988+50042+2042003[/url]
or online [url]
http://shop.oreillyauto.com/ProductDetail.aspx?MfrCode=WAL&MfrPartNumber=31548[/url]