Billet Bigbore Shovelheads
Introducing Sp's new Bigbore shovelheads !
These new heads feature Dual Decompressors for easy starting of big cubic shovels. Addtional fin area for superior cooling, and updated efficient combustion chamber designed to give 10.1 compression with a flat top piston in a 128" motor. Combine these with our Billet Big Bore barrels for engines with a 4.250 bore for the baddest Shovel or Panhead the market has ever seen.
Heads come standard with a 2.100 Int X 1.710 Exh. Heads use a 1.870 throat and flow 290Cfm@.700 lift @ 28" With proper cam selection,exhaust and carburation a fire breathing 135hp 128" motor on pump gas is only a bolt on away.
$2139.00 Satin machine finish complete PR Stage1
2339.00 Satin machine finish complete PR Stage 2
$2639.00 Show polished finish
All heads come hand blended and the chambers hand blended. Properly set up engines should be able to run at 210lbs cranking compression with pump gas and no detonation.
I will be working on a true raised port rectangular port head over the next year with flow numbers in the 350cfm range for big big power gains.
Stage 1 Flow numbers @28" 2.100 with 1.875 Throat
.100 -78cfm
.150-109cfm
.200-192cfm
.250-173.5cfm
.300-201.5cfm
.350-230cfm
.400-245cfm
.450-257cfm
.500-265.5cfm
.550-274cfm
.600-278cfm
.650-284.5cfm
.700-287cfm
.750-288cfm
.800-288cfm
Stage 2 flow numbers @ 28" 2.100 with 1.90 throat
.100-85cfm
.150-116.4cfm
.200-148cfm
.250-180cfm
.300-214cfm
.350-233cfm
.400-254cfm
.450-265.6cfm
.500-274cfm
.550-283cfm
.600-288cfm
.650-293cfm
.700-296cfm
.750-302cfm