I just got a set of 4.030 Wiseco flat tops - 5.4cc Pro Lites and the compression with 58cc head is 11 to 1. They are free and really want to use them with the rebuild I am doing. Is there any way of running this with stock heads without having to unshroud the valves to add cc's and polish chambers?
The pistons are forged 4.030" 3.48" 6" set ups that are strutted?? And only weigh 386g. They use 1/16 1/16 3/16 rings.....They will be going into a freshly machined block. Wiseco K061A3 part number.

 

Put um in they will be fine. 12-12.5 is not uncommon with a big cam. Find a DCR checker on line and follow directions entering your cam spects.
Stay below 9.0 to 1 and it's fine. Don't go to low as ya will leave a lot on the table.

 

same as above. You can run them no problem, but need to check it against your cam to see where your DCR is. I ran 11.3:1 with a 8.9 DCR and everything was fine, just had to be careful with the tuning.

 

Ran 13.0 with an 847 for about a year on pump gas and daily drove it. (over 10k miles in 1 year)

It would ping if you bogged it down really bad, but with a little change in driving habbit it was fine. If you put it in 6th and floored it at 40mph it would ping. Normal driving or flogging the car it never knocked. I suppose I could have tuned around it, jut learned to always downshift when passing etc.

 

12.2:1 with a small emissions cam on 93 pump gas. Not sure what my DCR is though.

 

>12.0:1 here and no pinging on 91 octane. As racerdude said, pay attention to DCR, and I would add pay attention to quench too. Both pay huge dividends in avoiding pinging and maximizing power.

 

Ok, I will be running a small Ai cam 208 / 221 525 / 540 112lsa so the bleedd off affect might not be present.
Is there a good thread someone can post about quench area?
For head gasket should I run the stock thickness?
Also, as a side question, when setting up an engine for N20, its best to open the ring gap a hair more correct? I talked to the Wiseco tech line and they did not say if I could run spray but only that they are forged, strutted, light weight.....any comments on that?

 

Talk to Phil about your quench and ring gap.

 

I agree!
Phil should be able to recomend quench/deck height compression ratio etc


Running a little more than 12:1 in mine no problems by my AI cam is bigger than yours (more lift and duration)