Thor21

I am currently working on fixing up an 83 GS with a blown 12A and plan on going with a 13b. I want to stick with carbed NA power for now and wanted to get some info. I am debating on whether to go with a 6 port S4 or S5 motor or try to find a 4 port 13b. I am not planning on bridgeporting or anything too serious. Would a streetported 4 port be comparible in power to a stock NA 6 port?

Latin270

Go carbed s5. Thats what I did and I have no regrets!

Siraniko

iTrader: (13)

no

Kenku

Really depends on the streetport.

steve84GS TII

Yea,there are many levels of streetporting.
And,more ports dont always mean more power.
The 6 port engines make smooth,linear power due to the correct,sequential actuation of the 6 intake ports.Its done for predictable,factory-friendly type power delivery.The dont just all open up when the throttle is mashed,its more like VTEC,with additional breathing coming online as needed,to build power without bogging or flatspots.
A streetported 13B 4-port can destroy a stock 6-port with minor add-ons.

Latin270

There wouldnt be any sequential activation of the aux ports if one decides to go carbed. Actually a 6port IMO runs strong by simply porting out the exhaust (remove difusers) and adding the pineapple racing aux port sleeves. Throw on a RB intake manifold or Jaytech and a nice holley 600 or 650. Thats it. You'll have yourself a nice streetable 6 port 13b w/ *****.

Siraniko

iTrader: (13)

joecoolly14

I have a Streetported 6-port with a 2nd Gen intake manifold with streetport exhaust..and it runs like a champ..very smooth and strong

Thor21

Thanks for all of the great info, I am open to either engine right now. But it looks like I will probably end up going 6 port since they are more available.