what size domes

[chayote86]

I bought a cool head but need to figure out what size domes to run. I got stock ported jugs, 39mm pwk 2into, v3s, cpi oof, i live in carthage mo 64836 ill find out the elevation not sure if it has anything to do with it or not. Thanks Ro

[rubberneck]

Yes elevation has a lot to do with it, as well as how much timing you are running and what fuel you intend to run

[chayote86]

Elevation is 1004ft and im running stock timing as of now on 91 octane

[rubberneck]

probably 21

 

edit: here is a helpful link http://www.nossmachine.com/banshee_heads.htm

[chayote86]

I think the head came with 21's

[rubberneck]

at lower elevations, 21s are generally accepted as a pretty safe size for pump gas

[chayote86]

The ones i bought have 18+2 on them so there 20cc's right? I feel stupid asking cuz your boi can add but not sure if it will change height or anything

[Jereme6655]

You sure you don't have a 4mil? Every builder has their own way of marking things.......but I believe that the 18+2 means they are 18cc domes and set up for an extra 2mm of stroke. So Im curious if your crank is a 4mil crank. Either way 18cc domes are tiny and usually mean that you should be running race fuels.......depending on elevation of course. But unless your up near the top of k2 you may need to check your compression before running that thing on pump fuel....

[chayote86]

Ya they are 4mill domes. Thanks im going to try and swap these for 21cc domes on the trade section. Thanks again Ro