I am rebuilding/porting my streetported (previous owner) s4 tII. I realized that the intermediate housing wasnt ported on either side. Are these supposed to be ported? I thought you ported all ports in the engine. sorry for the noob question but it is my first rebuild.

thanks,

spencer

 

Depends on what you want from the engine! I'm installing a half bridge, thats a street port on the primary and bridgeport on the secondary.



You do need to think about the big picture. If you have different porting, primary/secondary, then you need separate pimary/secondary control. The big webber 48's I got for my motor will not work well with the half bridge, so I need to go a 4 barrel carb route. For the half bridge, the theory is to keep the low end performance, while getting most of the benifit of a bridge port at the top end.



The previous porting may have been very specific or may not have been done by someone who knows what they are doing!

 

your 48s are more then enuff carb for a half bridge. even a small full bridge. we run 42s to 48s on monster street to half bridges on ower race motors due to rules, not the half bidge that was just for fun. but anyways on a 6 port 48mm street port motor we pullin 240bhp on 87 octain fuel. i myself am not a fan of the holley set ups on rotary motors. i have customers who had me build motors for them with holleys and a mounth or 2 later they wanted me to pull the holleys and replace them with webbers.



webbers are far far easyer to work on and tune in then a holley as well.





now for the portin. ya i always when i port a motor do all intake ports , but i not always port the exhaust ports. that depends on what rotor housing i am using in the build.

 

well i upgraded to a bridge port, so your saying i should streetport the intermediate housing/primary ports? Im looking for mainly top end.

 

to me, it really makes no sense porting an engine and leaving the primary ports untouched. you can use moderation when porting an engine. port for the results you seek.