I've ordered more parts and will be updating with more progress soon... Cant wait to have this thing running so I can scrap my current junker.

260S Comp Cam

Doug Thorley Tri-Y Header from Jegs

From LCE:
Pro Clutch Kit
Electric Fan
various block off plates

 

Nice build dude!

Question: Where did you find the info about the head? I thought any 20R head would fit on a 22Rblock? Also what is the advantage of this?

 

I'm no expert, heck I haven't even been working on cars that long. But I've gotten the vast majority of my info thus far simply by spending time looking on Google and forums. There is tons of info out there, if you can find it an make sense of it you can do a lot.

And yes, you should be able to get any 20r head on most 22r blocks with minimal work. For 22r blocks up to august 84, a 20r head is direct bolt on; later than that and you have to do some machining.

The 22r head has larger ports, so in theory it would be able to flow more air. However it also has "vortex notches" which are essentially large ridges that come down from the top of the port perpendicular to the path of airflow and curve around the valve in a semi-circle. The vortex notches create an impediment to airflow which should help with low end torque but it also lowers the movement of air volume in the upper rpm ranges; makes the larger port sizes kind of moot for going fast and/or reving.

The main advantage of the 20R head is different airflow characteristics; it has smaller ports so in theory its overall possible airflow is probably lower than the 22r head. The smaller ports restrict airflow more than the 22r ports so low end torque is pretty good. But it lacks vortex notches so the ports actually have less of an impediment to airflow at the valve bowls as rpm increases; it’s pretty much a straight shot to the valve opening making it friendly to reving and top end power. As well, the 20R head is easier to do port work on supposedly as the vortex notches on the 22r head are difficult to get a tool around in the ports.

 

Very informative thanks dude! I have always heard the 20R head on 22R block, but never could find the explination behind it. Now to go find a pre-august 84 22r in a junk yard!

 

Ok for my future reference and anyone elses that might need the info some day: With the later 22R blocks what part of the 20R head has to be machined to work?

 

Don't recall actually but I think the latter 22r blocks are shorter with a taller head. Would require the 20r head to be shaved some so that timing geometry is still correct.

Went to the junkyard today and found a 5 speed manual transmission to replace my 4 speed. Should be fun with the 3.154 rear end.


Going to make some time next week so I can finish this build up, its taken way too long.