Hey guys does anyone have pic of the inside of a std cosworth plenum?
ta matt

thanks mate, this settles a debate with my father, prior to me continuing my hunt for a cossy motor, any ideas which is the best one to look for mate? YBT? YBJ? or certain colour rocker cover?

Plenum order of preference...Firstly a fully custom made and properly engineered inlet and plenum....Then:
1. RS500
2. small turbo Escort Cossie
3. big turbo Escort Cossie
4. Sierra Cossie

Yes to 16mm plenum spacer.

281kW atw with a stock 1986 YBB arrangement, but will be trying a new plenum to see if this changes the power (for fun / R&D only), but likely this is not the source of restriction at all. Also looking at a longer inlet, all custom (this is specifically for more mid range, again an interesting R&D project)

Conclusion, if you are are chasing 600hp then buy the best, else probably there is no absolute requirement...

...and on the topic of engines, then use the same order of preference too...Though what you really want is a head that is not soft and bores not too oversize...You could buy all new at cost but less risk...The alloy blocks look to be brilliant and with a longer stroke crank, the cubes go up, sounds like endless hp to be had...

Matty-Tyler

thanks mate, this settles a debate with my father, prior to me continuing my hunt for a cossy motor, any ideas which is the best one to look for mate? YBT? YBJ? or certain colour rocker cover?

 
some info which might be useful, the cossie engine in its original form was naturally aspirated and given the code YAA
 
YBB is the most common which was fitted to most 3 doors & Sapphires
YBD was the rs500 motor essentially
YBG was the late sapphire, these engine had the green rocker cover
 
inlet manifolds vary, as pointed out above. what power are you aiming for? you dont really want to over spend on something that is needed. Unless you are going for over 500hp,  a 4x4 inlet with a spacer is more than enough.