I have a 1985 gsl se that I am restoring and building. I heard recently that you can get greater power gains out of a 12a. What is a better motor to build? I am not trying to build a track car, just a fast street car. In the future I would like to do a bridge port.

 

You can get greater gains on a 12A because the factory exhaust ports are so small. A bit of porting nets a great improvement. However the engine will still make less power then if the work was done to a 13B. The gain on the 13B is just not as great as compared to the 12A because it's a better platform from the beginning.

 

I would stay with the 13b that that car came with....i think it is easier finding parts for a 13b and also as posted by AC you can put the same money into both engines but the the 13b will still be out on top... the 13b is also a better developed engine.. the 12a is great but the 13b had its high points over the 12a they would both be fun builds....

 

no point in turning putting a 12A into an SE. just streetport your 13B and invest in good engine management, you'll get a fast street car! a few well-thought-out improvements made during the engine build are key, but you can keep it reasonably affordable and still get real results.

only do the bridgeport if you're ABSOLUTELY sure that YOU can live with it. doing it right will obviously cost more, but i'd still say use the 13B as a startpoint. however, i'd 86 the 6-port though.

 

13b requires computer work while a 12 a is stickly you work i have a buddy that races a 12 that mo fo is fast im thinking of it my self