Okay so my shop had the heads re-surfaced while the head gaskets were being replaced, also they ?reground? the valve seats

so im wondering if i would notice a performance increase when the car gets back to me, compared to how it ran before i drove it to the shop?

does the resurfacing of the heads mean a higher compression ratio, or does it not take enought off to matter?

 

Usually the decking of the heads will result in a minimal increase in compression. If warping caused them to take a thick slice off the heads, and they used a thinner than stock gasket, then it could amount to a decent increase in compression. If the valves were not sealing against the seats, and the guides were passing oil, restoring the valve guides and valve seats can definately result in power increases. Both by increasing cylinder sealing and by minimizing oil contamination that contributed to detonation.

 

It things were not right you should get some increase in performance.

Did you have them do a 3-angle or 5-angle valve job while in there and back-cut the valves??

 

Sometimes I wonder if shops just tell you your heads need surfaced just to make money. I've never taken a set of heads to my machine shop and had them not need surfaced. I've rebuilt a lot of motors in my day and not once have I ever had a failure when I didn't have the heads resurfaced. These are motors where I was just usually freshening things up, gaskets, rings, bearings, seals and so forth.

Even heads I've taken from motors where there is no problem seem to need resurfacing, I just take them in for cleaning and checking. My LT4 heads for example, I just took them off to do the porting work and have a 3 angle cut done. Of course they told me they needed surfacing. I wonder if they are just taking a VERY small amount off to make a better sealing surface or just taking some off to show they had been surfaced to charge me.

Either way it's starting to pizz me off, I'm starting to feel like I'm getting a rip job rather than a head job.

To get back on subject it really does depend on how much they had to cut to make them flat again. Without CCing them before and after no one really knows how much the compression changed. Even if you did know I doubt you'd feel anything from a small CC change using the stock gaskets, maybe.

The bigger question becomes for me is how the surfacing is going to affect my intake sealing? Surfacing heads just to make money and leaving a customer with an intake that doesn't align right is just wrong IMHO.

What happens when you're heads really do need surfaced? What if there isn't enough left because they just wanted to hose you of some bucks the first time surfacing them?

For these reasons I'm considering buying a true straight edge, I'm losing faith that EVERY darn head I take to the machine shop needs surfaced. I could be wrong but my gut is usually right when I feel I'm getting ripped.

 

It's only a clean up, not much more than honing cylinders and the cost is minimal considering the investment. I think you're gonna notice better performance simply because of the valve job and I certainly wouldn't worry about the intake misaligning.What compression you do gain won't be anything you'll really notice.