Thanks curtis, yes it is limited street and I have been mulling over the compression as it doesn't see much street use. Just drive it to a car show and some short cruises. So, its not like I am filling up with race gas every week. Some day I would like to get it into Hot August Nights...that would be a blast.
The reason I was thinking of going large was that was the only way I can make the hp I want with lower compression. It takes about 900-950 to get a 3500lb car in the low 9's. Mine weighs 3200. It will take 1100+ to get in the 8.50 heads up class. I wanted to try and get has close as I could so I don't have to run a lot of nitrous. 250 shot or less...I was planning on running 100LL playing on the street and race gas on race day. I might be able to go a little higher cr with the 100LL or I could mix some race gas with it. Anyways, it would be a lot easier if I would just move up in compression.
On Shaffiorfs 632's there is a 100hp difference between the conventional and 18* head at 10.75...just throwing that out.