Streetporting:
Also available is streetporting. Streetporting (Sp) is an internal intake/exhaust modification that can only be performed while the engine is disassembled. It is similar to swapping cams on a piston engine, it affects airflow (think lift) and timing (think duration). SP’ing is to be regarded as any other airflow mod (like air filter or exhaust mod) as far as power increases go. A large Sp on a stock car, for instance, might not be as noticeable as a small Sp on a modified car. Sp’ing doesn’t really change your idle ability, though a large SP can change idle tone a bit. IT does affect your driveability, mainly your low end pull. Especially, for instance, pulling out on a steep hill from a dead stop.  The gains on top end are definitely worth the risk, however. Gains from an Sp on a nonturbo are not large, but still worthwhile, around 5-15hp depending on mods. Gains on a turbo model are usually quite a bit higher, anywhere from 10-25hp+ depending on mods. Do not plan on passing emissions sniff tests with a port, though it still may be possible with effective emissions tuning.

I generally keep my ports fairly conservative, which is good for a street car. I have went to performing one standard style streetport per application (turbo, non, FD) which I consider normal. Exhaust ports are opened slightly earlier but kept mild for low noise and emissions. Most porting is directed on the secondary intake ports where most top end power is made; primary intake ports affect idle and low end and are ported lightly. Below are pics of standard 87-95 turbo porting, secondary stock port on the right, streetport on the left.

Stock 87-91 intermediate porting vs. streetported:

Exhaust porting:

Nonturbo 6 port engines, auxiliaries (5/6 ports) only:

I have recently developed a special version of SP unique to the 6 port nonturbo engines (84-91 13B). This port allows for a nice top end power increase with absolutely NO decrease in low end pull, driveability, or even emissions testing. This is accomplished by only porting the 5th and 6th intake ports, and a very light exhaust port. The “lower” 4 intake ports, responsible for idle and low rpm driving remain untouched, and so do the normal driving characteristics of the engine. Only at/above 3800rpm,when the auxiliary ports open, does the porting take effect and move more air through. No emissions test that I am aware of, even the dyno/roll test, pushes the engine to the point where the auxiliary ports open, therefore this is a good way to “hide” your performance gains from the emissions test. For those who don’t care about this, I can/do still port all the ports of a 6 port engine, though there isn't much performance gain for the 4 smaller ports, and there isn't much room to port into them anyway.

For exhaust ports, I cut out the nonturbo exhaust diffusers with a torch on all streetported engines. This leaves a port sleeve basically the same as a turbo sleeve. Noise is slightly increased, as well as flow. The port shape itself is not altered.

Nonturbo 6 port engines, full streetport

For those wanting more performance from nonturbo 6 port engines, I port all 6 intake ports plus both exhaust ports (including diffuser removal). There is not much room to port into nonturbo irons but this takes full advantage of what is available. Cost is $300.

Cost of streetporting for 87-95 turbo is $300. Cost of porting the auxiliary 5/6 ports only for nonturbo engines is $200. Cost of porting all intake/exhaust ports on nonturbo engines is $300. I will soon be offering turbo and 6 port half bridgeports as well. Note that I will not perform porting on any plates and then ship them out, porting is only available for engines being built here. Porting is a break-even proposition most of the time, the engine itself is the only profit.