i know there is a thread somewhere on here doing a step by step on this swap.. can someone find it for me. ive been useing the search button and have found everything under the sun cept the thread im looking for. im pretty sure my motor is an 85 and down so this swap should be a direct bolt on. ive heard from someone that this will bump my compression to 11.5:1 but this is the first ive heard of that, is this true? thanks! i guess i failz the internetz tonight
you want a -83 block and a 20r head. technically the block change was in 84.5 but then you need to know the difference between the blocks. easiest way is the newer "laser" block castings are sharper and there is a mickey mouse shaped port casting near the dip stick for a turbo oil feed. assemble as normal using a dual timing chain for added bad assedness. post pic of exhaust side of block and ill identify it for ya
Well, if you have a Domed piston block (pretty easy to tell), a 20R head will bolt right on. 81-82 double chain timing set will bolt right on. It is better than anything else. Your compression will be like 9.7. Not 11.5+. It will be completly streetable on 87 octane. Ive just had my head milled .050 thousanths. I havnt cc'd it yet, but it should be around 10.5 according to the LC guy. He said that you could mill it as far as .120 thousanths no problem. The casting is bookoos thick. As far as swapping the head.... Use a 22R headgasket. 20R intake manifold 20R intake gasket Slight rerouting of heater hoses If your goal is power, use sidedrafts or a holley. You will not be dissapointed. Mine ran AWESOME with stock 20R valves. Should run more awesome(er) with stage 5 valves... Cams are interchangeable Exhaust is interchangable Its really an easy swap. Well worth the power. Any q's just ask.
thanks for the help, ill post pics of the side of the block tonight when i get home from work. The 20r head i have needs a refresh so i might do a valve upgrade at the same time. Ive had this 20r head and block sitting around for awhile and nobody wants to take it off my hands so i might as well use it in my daily. ive heard that you are supposed to switch in the rocker assembly from the 22r head into the 20r for an upgrade.. thats correct right?
I wish.. I ended up cutting the crap out of them. But an unmilled, stock valved head that is mildly cammed (280 and under duration) will not have these problems.
