Visit The Dirt Forum for More Information

Author Topic:   350 Dble humps
Dirt Full Roller

Total posts: 58
posted June 03, 2005 09:37 PM  
I hope this is not a stupid ??? can a guy put a set of 350 Dble hump heads on a 305 and if he can do you have to change anything? are there any advantages to doing this? reason being is rules say 305 block and I have a good set of dble humps just setting around.


Dirt Forum Champ
Total posts: 968
posted June 04, 2005 04:07 AM  
Bolt em on!

Dirt Freak

Total posts: 385
posted June 04, 2005 08:05 PM  
Without aftermarket pistons those will drop the compression a lot - 305's are like 55cc, and the double-humps are 67 or 76cc!

As for physically bolting them on - they'll fit.

Dirt Roller

Total posts: 15
posted June 04, 2005 09:00 PM  
find a machine shop to anglemill the heads and intake to 58 cc and you will be hard to beat.

Dirt Full Roller

Total posts: 33
posted June 06, 2005 11:26 AM  
Not all 305 heads are small chambered. Most double hump heads are around 64 cc's. CC a chamber on your double humps and then do the same on your 305 heads. If the numbers are close, you wont see much of a compression change and the double humpers breath a lot better.

Dirt Forum Champ
Total posts: 1019
posted June 06, 2005 11:33 AM  
Exactly right, the ports in the ol' double hump heads will gain a LOT more power than the 305 heads even if left at 64cc. Stock 305 heads stop flowing or making any HP worth a darn at about 4500rpm, so it doesn't mean anything that they have small chambers, since many of them also have very small valves, bowls, runners, etc.


Back to the Archives