I currently getting my engine rebuilt with an extend port due to my blown apex seal..... does anyone know how much power it is possible to extract from a 12a with extend porting.

Cheers,

Mick

ps. ROTAZ R SIK!!!!

 

How tall will they be? I'm going to extend port an old 4 port 13B this week (or as soon as I take it apart). The port template I'm using has two sets of ports; one mild and one extend. The mild is 53mm tall when measured from the middle of the bottom to the middle of the top of the port. The extend is 58mm measured to same way. I'm not sure if that's the right way to meaure them, but they're both longer and wider than stock. The exhaust ports will be taller than TII ports with a little D shape, or maybe just straight.

As to how much power you'll have, it depends on everything else like carb or FI, exhaust, etc.

 

Im not sure of the size of the ports but i will be maintaining the stock four barrell for a while and i have extractors with 2.5 inch exhaust........

I have to wait 4 more weeks till i get my motor but i will keep you posted!

 

Ok, cool. This 4 port engine I'm doing has a Dellorto and RB header. It also has nitrided side plates so they definetly came from a 1st gen, or possibly a japanese engine. The 13B rotor housings have three or four little chunks of aluminum around the spark plug holes. I was told that means it came from a japanese spec engine. The ports may only take a mild port. I'm not sure how much 'meat' can be removed.

 

I think that the only limit to how much 'Meat' can be removed is to the extent of the exhaust port insert....

All i know is that i have to wait 4 more weeks untill i get my Beast back! and i just cant wait!!!

at the moment im driving my old 929 coupe 76'
its about to blow!!!!!