ok, i actually have almost all the parts needed (including the block) to do the s5 13b n/a swap in to my 84 gs. the thing is i am starting to consider sticking with my 12a and rebuilding it with a streetport and possibly going turbo. granted it would be kinda nice having the 13b in there, but it's nice to be able to say i have the original motor in there. :-D plus i like the way it revs. one of the main reasons i have come to this possible change is the influence of a few guys out there with 12a's that are pushing over 200hp. the way my car drives now is great. it pulls beautifully from 2,000rpm to 8,000rpm. if i do the 13b swap (i would be going carb) i would have to fore-go the 5th and 6th port sleeves and would lose a considerable amount of smooth rpm capability and my top hp possible would only be around 180 or so. i know street ports dont really give you much on the 6 port motors. soooo, my racing beat holley 6port intake manifold, injector plugs, gasket (all brand new) might be for sale! what do you guys think? am i an idiot?

 

I think the 12a idea would be cool. We need some people to stick with the 12a lol. I'll still have one in my racecar (rules require). But I'm going to go 13bt in my streetcar.

 

the 13b sounds better, and you can make more power with it.

but its up to you.

 

Your call of course, but the S5 13B is a better engine than a street port 12A IMO. 180Hp is what they make stock! Reverting it back to carb thus ditching the variable intake and the 6th ports will make it have less low-end, but the top-end should still be pretty killer. With the standard headers and exhaust you should be around 200Hp. Thats about as much as you could possibly expect with a 12A SP. Not to mention the higher compression rotors, hardened gears, and better seals. They have an 8k rpm redline stock!! They come with bigger stock ports than earlier models, and so less extra casting, thats why there isn't much to be gained by porting - its already been ported.

Going turbo is an entire different playground. If you can only do turbo 12A or S5 swap, thats a tougher choice, because there is obvious tradeoffs. There is no cheap way to go turbo, and there exists the everpresent possibility of destroying your engine under boost. Definately more potential power with a turbo though.

Low cost, high power, and reliablity. Choose two.....

 

vac do the 13b you will be happer!!!!!!!!!!