Me and my dad are prepping and engine for pure racing, boosting. now its a 12a and its gona be carbed and bridged ported. we are looking for around 350hp and i have heard that the rear cast plate on the 12a may crack over 250hp. the solution to that was to find a 74-76 13b rear cast plate, which are stronger but impossible to find, the question isHas anything been done to reinforce the rear cast plate of the 12a for such hp or am i sol on this one?

 

Add extra dowels. Talk to Robert at Rotary shack or research doweling/pinning an engine.

 

the rear plate wont crack on an N/A application....thats on turbo motors only. 12-A and 13-B plates are the same ****. just look for the ones with tall ports such as the newer 12-A

 

I am boosting and the engine is an 84 12a, so i would imagine that i have the newer 12a so it would be the one with tall ports? right?

 

check out mazdatrix or guru for the oversized stud kit or hardened kit, will run you about $500 BUT i've only seen them on 13-B's not 12-A.

 

no, mazdatrix has a stud kit for the 12a as well, i emailed them on what needs to be machined and stuff to make them fit, still waiting for an answer. So if i dowel pin or stud kit, i should be k with the rear cast plate taking into account that no detonation will occur.

 

if you do not have detonation, or misfires or cross triggering of the ignition (its very bad if the signals get crossed firing the trailing early = broken stuff) the stock plate should be fine @350hp.

if you have some kind of cross triggering of the ignition, or detonation, its going to break dowels studs or not

 

yeah thats what i ma saying, if i dont have detonation i should be fine.