Re: 356 & 359 info and choices.

Posted by HH56 On 2022/7/19 10:05:26

Can't help with your swap question but yes it is possible the head was modified. Be very careful of any different heads you find or use. Even with brand new heads, there is very little valve to head clearance when valves are fully open. Unless you know for sure the swap head has not been previously milled always test it first.

Easiest way is to take a bit of modeling clay and place a thin layer in the head above the valve edges. Lay head on the block and rotate the engine thru a couple of revolutions. Check or measure the thickness of clay where the valve edges have made an impression. If you have clearance on all then the headgasket will add a bit more and you are good to go. If a valve actually flattens the clay and touches the head, you will need to provide clearance in some way or find another head. This will be a valid measurement if the engine has solid lifters that were installed to spec but if hydraulic then you will need to find the lifter lift spec or otherwise account for the additional lift when the lifters are pumped up.

It is an unfortunate fact that many have decided to have a head smoothed or a perceived warp removed and when head is back from the machine shop, bolted it on without testing and tried to crank the engine. That is when the valves bend or otherwise damage something in the valve train. It was later found out the head had been machined once or twice before and the last bit taken off was too much and head is now only good for scrap metal. I would be very careful of any loose ebay heads. They may be good but they could also be from someone trying to make up for his accidental introduction to scrap metal.