I know many people have covered this topic on here before and on many other sites and I have done my research but I still some have unanswered questions. Okay so first off Im doing a rebuild on my 13b rew fd and I want to do the cosmo 13b re uim/lim swap with the 20b tb, while I have it all apart. I know the runners are different and need to be ported on the rew irons, but I was just wondering if it would be wiser just to buy 13b re cosmo irons and use them instead. I just need to know if there are any differences between the two other than the intake port sizes, and will they work with the rew housings? or should I just port the rew irons?

 

Easiest thing to do is port match the REW irons since engine mounts are not in same location on both blocks.

 

oh okay thats what i wasnt sure of, and once you have it ported out the cosmo lim will bolt up no problem to the existing bolt holes? I was also wondering if any one makes an adapter to bolt the cosmo uim onto the fd lim

 

Cosmo LIM bolts to the REW block no problem. There is no adapter for the Cosmo UIM to FD LIM. There isn't enough height anyway. You already have to cut 1/4" out of the motor mounts as it is to get it all to fit.

 

Off of the bushing for the mount? I didnt know that part. Learn something new everyday

 

easiest thing to do is use poly mounts and cut them down 1/4". I think I did 5/16"

 

alright thanks, really appreciate it Is there anything else i might need to watch out for?

 

Throttle cable needs rerouted. Tps needs redone if you're switching to cosmo tb or an adapter if using fd tb. Oil filler neck usually hits the greddy elbow. That's the main stuff. Then it gets more involved depending what you're doing with your turbos. I'm in the process of doing It now, can u tell?

 

Beachcat.... Mamba and silver know there stuff.. Great info from good knowledgeable dudes... I'm also in the process doing the 13b Cosmo manifold setup good look with the build let me know the outcome!!!

 

anyone know if the xcessive lower manifold has enough material to port it cosmo-size?

 

Thanks everyone for all your help, you guys just saved me a whole lot of time and effort! Now I know what needs to be done to make this thing work. I really appreciate it!

 

Greddy elbow will not bolt to the Cosmo TB.

You will need to block off the ISC on the bottom of the TB if you want to keep the coils on the block. 13B-RE & 20B BOP's

 

Yes minimum 1/4" of the mounting poly mounts, also inwoukd recomend you get a aftermarket oil filler tube like the one IRP sells, i had clearence issues with the stock one.