<A target="_blank" HREF=http://LCengineering.com>LCengineering.com</A> states that for a 20r head on a 22r: (Backwards from what you want)
In order to keep the cam and crank centerline consistent with an 85-95 head, you must mill the 20R head to a measurement of 3.130 (measured from the bottom of the front cam journal to the deck of the head). Remember to re-machine the oil passage back into the deck surface of the 20R head after milling to retain oil passage to the top of the motor.
So, I am assuming the 22r head on a 20r block will not work because the 22r head is too short for the 20r block.
ditch the 20r block, put the 20r head on the earliest 22r block you can find. the "pre-laser" block is the one to get, i believe its 83-84??. their easy to come by. since your not talking about lots of mods...youll be happiest with the 20r on the 22r block not vis-versa.
Call John at LC Engineering. The problem lies in 2 areas, first the timing chain won't fit without some help and second I think one of the ports will be different, intake I believe, round vs square..Curt
Everyone is right about going with the opposite of what you are asking for the best performance. I used an 82 block and you don't have to shave the head or block to do it. Try doing a search on this topic and you will find a thread about it with more info. I think I said alot more on there and some others did also. Another advantage of the early blocks is they have a dual timing chain stock.
It's Shane from AOR. I'm still up here at Wyotech, about to graduate March 21, 2003. I'm in the process of rebuilding the 22RE that was in the little red pickup I had. There's a good website called www.toyotaperformance.com He's got all the specs and everything for the 20R's, 22R's, and RE's.
I put a Schnieder Racing Cam in it, along with metal backed guides, and a ton of other performance upgrades. I'm building it for my pops to put in his 4-Runner. He wants to be able to tow with it at highway speeds, and still keep it emissions legal. I'm giving him the engine out of my truck because I've got a 3.4L going into my 7open truck, that I'm building up here. All that work I put into the sponsorship proposal that I was working on before I left really paid off! I 've been able to get a lot of sponsors who are helping me out big time. The Chassis Fabrication and High Performance Engines program up here is awesome and I've learned way more than I ever expected. Due to my sponsorship work I've met so many really cool people in the industry, that are really giving me a helping hand to reach my goals. I have a 95% overall GPA, and will be graduating at the top of my class. I've recieved job offers all over the country for automotive, and fab work. And to top it all off, my & truck is really coming along well. I'm hoping to be racing by September, if all goes according to plan. Haven't talked with you for quite awhile, let me know how you and Paul are doing. Now you know where to find me.
It is possible to run a 20R Head on an 85-95 laser block. In order to keep the cam and crank centerline consistent with an 85-95 head, you must mill the 20R head to a measurement of 3.130 (measured from the bottom of the front cam journal to the deck of the head). Remember to re-machine the oil passage back into the deck surface of the 20R head after milling to retain oil passage to the top of the motor."
thats for the 22re laser block, ive heard that even less has to be done to run it on a 80-84 pre-laser block.
why do we do this? to tell the truth im not completely sure myself. looking at the specs, its clear that the pre-laser 22r as well as the laser 22r has a better bore size (92MM - 3.622"), but the pre-laser block has a better deck height than the laser block ( 9.120" (Crankshaft Center to Top of Deck) on the pre laser) and ( 8.950" (Crankshaft Center to Top of Deck) on the laser block. these specs are better than the 20r block in most areas.
then, looking at the cylinder head specs (below) you see that the older 20r and 22r blocks have bigger chambers.
1975 1982 20R Cylinder Head
Round Intake Port / Round Exhaust Port
80 / 81cc Chamber
In. Valve Dia. 43mm / Ex. Valve Dia. 35mm
1985 / 95 22R / RE Cylinder Head
Square Intake Port / Pear Shaped Exhaust Port
58 cc Chamber or 22RET (Turbo)
In. Valve Dia. 44.5mm / Ex Valve Dia. 36.5mm
it looks like the idea is just to match up the best parts with each other for the optimum deck hight, chamber size, bore size, and im guessing head flow (rates not mentioned on flow but ive heard the 20r has better flow than the later modles).