i picked these heads up for a 100 bucks, they look like they are machined for bigger valves, not sure what size, also look like they have new rocker studs but no guide plates i was thinking about getting them ported and new valves installed and swaping them when i install my cc306, i already have new springs on the way and 1.6 rrs, does anyone think these heads would make a big enough difference for the trouble id be going through to install them

 

I think so. If you port them you are ahead of the stock heads. Better breathing = more power.

 

thats what i was thinking im just wondering what size valves they are machined for do they look much bigger than stock?

 

They do look bigger, a machine shop could mic them for you. i'm sure you could do it yourself but i'm not sure exactly how they are mic'd

 

yea dad said he had something to mic them with but i believe im going to just go ahead and drop them off at the machine shop and get em checked for cracks and see how big the valves are

 

Those look like 561s which are the less desirable casting for porting. Add on top of that that they've been messed with before by unknown hands and I'd sure be trading them for some untouched 374s / 643s.